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PerOMAS Thesis to obtain the Master of Science

1. 09 00 08 00 Add Action Action Alias Action Ji Set_Lights Argument False True Figure 4 19 Configuration Menu 55 4 3 Deployment at IST Taguspark From the planned architecture for IST Taguspark only a small part was deployed The initial plan was to deploy the system in an entire building zone but due to hardware acquisition constraints the pilot was deployed on a much smaller scale Six nodes were prepared but the current installed system is only composed of three nodes two Assistants and one Gateway Assistant distributed in a building zone as shown in Figure 5 1 The testing scenario is further detailed in Section 5 1 4 4 Summary In this chapter the implementation choices were described The chapter starts with a detailed description of the hardware architecture first the SBC then the rest of the sensors end peripherals Then the implemented software architecture is described in detail starting from the platform and tools used and ending with a detailed explanation of each layer and modules of the main application At the end of this chapter a working implementation of the system is presented In the next chapter this solution is validated using a series of tests 56 Chapter 5 Evaluation In order to evaluate the developed system several tests were performed Section 5 1 starts by describ ing the test scenario Next in Section 5 2 the detailed description of each test
2. As mentioned before the MySQL open source Relational Database Management System RDBMS will be used for storing the main application s data It was mainly selected because it is a widely used fast multi user and multi threaded database used for application development 4 2 4 Network Configuration In order to configure the node to connect to the multi hop ad hoc network a Bash script was developed The script configures the parameters of the wireless interface and associates it to the mesh network Then it requests an IP address from the Dynamic Host Configuration Protocol DHCP server which matches the node MAC to and IP As shown in Figure 4 11 every Gateway also makes a bridge between its two interfaces in order to allow the Assistants to access the Internet In order to secure communication between the nodes the Wired Equivalent Privacy WEP security algorithm was used to cipher the data It was used because the ad hoc mode used by B A T M A N 7http www mysql com 8https www gnu org software bash Shttp mosquitto org 10http pygame org 44 doesn t yet support the Wi Fi Protected Access Il WPA2 standard and the used wireless interface doesn t have support for the Wi Fi Protected Access WPA standard in ad hoc mode A solution would be to cipher the payload of every packet in software But since data security is not the main target of this thesis the WEP algorithm is sufficient to difficult eavesdropping and tamper
3. Learned sequences of acts that have become automatic responses to specific cues and are func tional in obtaining certain goals or end states 44 These habits occur automatically and sub consciously They are beneficial to humans because they free up resources for other activities that can be carried out simultaneously 3 Many routines that are related to energy consumption such as switching off lights are presumed to be under habitual control Thus habits can be further studied in order to better understand their impact on energy consumption Studies have shown that the human behavior in fact causes big variations in energy consumption 45 1 46 47 48 Recently it was demonstrated that the actual energy consumption caused by occupant behavior can account for 51 37 and 11 of the variance in heat electricity and water consumption respectively between very similar buildings 3 This values show that users can have as much impact on energy consumptions as the efficiency of the appliances or even the design of the building However just a few behavioral actions have been identified to impact the energy use leaving a large consumption variance unexplained One factor that is thought to have great influence is human motivation In 49 was studied the effect of motivation in relation to climate change taking into account socio economic differences The study concluded that there are energy variations that are not explained by occupant cha
4. It is also used in LoS Laser communications which can offer high speed data rates 18 Infrared Data Association IrDA is an industry driven interest group that provides a complete set of protocols for wireless IR communication that permit data communication up to 1 Gbit s standardized as Giga lR 19 2 2 2 Bluetooth BT BT also known as Institute of Electrical and Electronics Engineers IEEE 802 15 1 standard 20 21 is a wireless technology designed for short range communication of fixed and mobile devices also known as Wireless Personal Area Network WPAN 22 BT operates in the 2 4 Ghz short range Industrial Scientific and Medical ISM band and uses a radio technology called Frequency Hopping Spread Spectrum FHSS where every packet is transmitted on one of the 79 designated BT channels and offers data rates of up to 3 Mbit s BT uses a master slave communication model where one master device can communicate with a maximum of seven other devices in a piconet A piconet is an ad hoc computer network using BT technology where all devices are synchronized using the clock of the master Slaves communicate only with their master that controls the communication Besides having an active mode a slave device can be in the standby or parked mode to reduce power consumption 22 Two or more piconets can be connected to create a scatternet 23 in which certain devices simultaneous can play the role of master in one piconet and the slave i
5. each module contains a number of transistors to drive the coils which prevents current from surpassing the recommended 3mA from the GPIO pins Each relay works from 5VDC and is rated for up to 10 amps at 250 VAC The first module 4 relay is used to control the HVAC and the second module controls the lighting zones a A four relay module b A two relay module Figure 4 5 Relays used to control the HVAC and lighting 4 1 5 User Detection In the Office In order to increase the energy efficiency in every office the automation system will trigger rules based on the occupancy of the office The detection and identification of users will be performed based on their cellphone BT presence in the office since the survey done beforehand in Section 3 1 2 showed that 96 of the occupants already had a BT capable device This decision significantly lowers the cost of the system since the cellphones are used as an identification token and are usually always close to the user For the users that don t possess a BT device a Bluetooth Low Energy BLE Token could 39 be used instead An example of such device is the Qualcomm s Gimbal proximity sensor Series 10 shown in Figure 4 6 a These are low power low cost battery powered devices that transmit beacons at regular time intervals similarly to the ones produced by a BT cellphone when in discoverable mode These devices have a battery life of up to a year and communicate up to distances of 50
6. gains But since this was not the main purpose of this thesis it was classified as an enhancement and proposed as future work The Publish Subscribe module is responsible for assuring that the information is passed from the Assistants to the Gateways and from the Gateways to higher level Gateways As mentioned before the 11 http www sqlite org 46 Mosquitto broker which uses the MQTT protocol was installed in every Gateway The Publish Subscribe module then uses the python binder to connect to the broker in order to publish or receive messages A concept of message queues or channels is used to differentiate the messages A Gateway re sponsible for a building zone will subscribe to each of the channels in which it shows interest listening for Assistant message publications As presented in Figure 4 12 our implementation also divides the messages in three priority categories that are published and processed when received in a strict order This assures that important messages will be quickly sent and processed The MQTT protocol has three levels of quality of service for message delivery at most once best effort message loss can occur at least once messages are always delivered but duplicates may oc cur and exactly once assures that the messages arrive exactly once In our scenario the messages are sent assuring that messages arrive exactly once at the destination This approach simplifies the message p
7. vel Bom Muito Bom Excelente Outro 68 Bibliography 1 Guerra Santin O Itard L Visscher H The effect of occupancy and building characteristics on energy use for space and water heating in Dutch residential stock Energy and Buildings 41 11 November 2009 1223 1232 2 Marinakis V Doukas H Karakosta C Psarras J An integrated system for buildings energy efficient automation Application in the tertiary sector Applied Energy 101 January 2013 6 14 3 Huebner G M Cooper J Jones K Domestic energy consumption What role do comfort habit and knowledge about the heating system play Energy and Buildings 66 November 2013 626 636 4 ASHRAE S Standard 135 2012 BACnet A Data Communication Protocol for Building Au tomation and Control Networks American Society of Heating Refrigerating and Air Conditioning Engineers 2012 1 7 5 Kastner W Neugschwandtner G Soucek S Newmann H Communication systems for building automation and control Proceedings of the IEEE 93 6 June 2005 1178 1203 6 Bushby S BACnet TM a standard communication infrastructure for intelligent buildings Automa tion in Construction 6 1997 529 540 7 Newman H BACnet Answers to frequently asked questions Ithaca NY Cornell University March 1997 47 51 8 Snoonian D Smart buildings Spectrum IEEE 2003 9 Loy D Dietrich D Schweinzer H J eds Open control netwo
8. 2000 22 00 100ct Figure 5 5 Humidity Readings E d o nm E 2 E E 3 A AA a ER 02 00 04 00 06 00 08 00 10 00 12 00 14 00 16 00 18 00 20 00 22 00 Figure 5 6 Luminosity Readings e Mark 1 User 1 enters the office e Mark 2 User 2 enters the office e Mark 3 User 1 leaves the office Some aspects to take into account are the users thermal preferences User 1 had a thermal prefer ence of 22 7 C and User 2 of 24 1 C Following the sequence of events we can observe that when User 1 enters the office at around 2 PM the system starts the HVAC with the target temperature oscillating around the 22 5 C value The oscillation of the temperature was explained before and has the objective of only enabling the HVAC system when the temperature surpasses a certain margin which in our case is 0 3 C When User 2 entered the office at around 4 PM the temperature of the office starts to rise and stabilizes at around 23 5 C a temperature which is between the preference values of the two users Finally at around 6 PM marked by the third event User 1 departs from the office This leaves User 2 alone and the system reacts by applying its thermal preferences of around 24 1 C The graph also presents another mark Mark 4 were even though a user is present in the office the temperature keeps rising This phenomenon is due to the fact that the HVAC system of the building is shut down at around this time resulting in a
9. 5 3 2 User Detection Results A set of measurements were performed in order to determine the responsiveness of the detection sys tem The test resulted in a set of 25 measurements with an average response time of 7 01 seconds and a standard deviation of 2 48 seconds The cumulative distribution function of the readings can be 59 Power 2000 31500 1000 Power Watt 500 h ol 14 00 16 00 18 00 20 00 22 00 14Oct 02 00 04 00 06 00 08 00 10 00 12 00 Figure 5 2 Energy consumption spikes created by a 2000W and a 1500W rated heating devices observed in Figure 5 3 These results show that the system is fast in detecting a single or multiple users The detection of multiple users was not performed because of process that the sensor uses to detect users would have produced the same conclusion regardless of the number of users Very large numbers of users would have impacted the RF medium with noise causing miss readings and as a consequence detection delays One fact to be noted is that excluding the signal attenuation caused by the walls the system can detect the users at a distance of ten meters In the majority of the cases whenever the users have reached the door of the office the system already detected and identified the user without causing any perceivable delay from their point of view Probability 3 35 4 45 5 55 6 65 7 75 8 85 9 95 10 105 11 Detection Time s Figure 5 3 Cumulative distribution functio
10. FFD FHSS FO FS GPIO HTML HVAC 12C Change of Value CSMA with Collision Avoidance Carrier Sense Multiple Access CSMA with Collision Detection Cross site Request Forgery Dynamic Host Configuration Protocol Distribution System Direct Sequence Spread Spectrum Data Transfer Object European Commission Energy Cost Indicator Enhanced Distributed Channel Access European Home System Electronic Industries Alliance EIB Associations European Installation Bus Equivalent Isotropically Radiated Power Extended Service Set Engineering Tool Software European Union Full Function Device Frequency Hopping Spread Spectrum Fiber Optics File System General Purpose Input Output Hyper Text Markup Language Heating Ventilation and Air Conditioning Inter Integrated Circuit xvi IEEE IETF 1 0 ISM IST LAN LCD LED LNS LoS M2M MAC MANET MP MQTT MS TP NIST NoSQL O QPSK OSI OS PBKDF2 Independent Basic Service Set Integrated Circuit Identification Institute of Electrical and Electronics Engineers Internet Engineering Task Force Input Output Internet Protocol Infrared Data Association Infrared Industrial Scientific and Medical Instituto Superior T cnico Local Area Network Liquid Crystal Display Light Emitting Diode LonWorks Network Services Line of Sight Machine to Machine Media Access Control Mobile Ad Hoc Network Mesh Point Message
11. Queue Telemetry Transport Master Slave Token Passing National Institute of Standards and Technology Not Only SQL Orthogonal Quadrature Phase Shift Keying Open Systems Interconnection Operating System Password Based Key Derivation Function 2 xvii PEI PGA PHY PICS PIR PL PTP RADIUS RDBMS RFD RFID RF RSS RTS CTS SBC SLP SNMP SNR SNVT SPDT SPI SQL STA TFT TLS TP UART UDP Pin External Interface Programmable Gain Amplifier Physical Protocol Implementation Conformance Statement Passive Infrared Power Line Point to Point Remote Authentication Dial In User Service Relational Database Management System Reduced Function Device Radio Frequency Identification Radio Frequency Received Signal Strength Request to Send Clear to Send Single Board Computer Service Location Protocol Simple Network Management Protocol Signal to Noise Ratio Standard Network Variable Types Single Pole Double Throw Serial Peripheral Interface Structured Query Language Station Thin film Transistor Transport Layer Security Twisted Pair Universal Asynchronous Receiver Transmitter User Datagram Protocol xviii UI URL USB VLAN WEB WEP Wi Fi WLAN WMN WPA2 WPAN WPA WSGI WS User Interface Uniform Resource Locator Universal Serial Bus Virtual LAN World Wide Web Wired Equivalent Privacy Wireless fidelity Wireless L
12. amount of thermal energy when the building will be mostly vacant during the next day Limited Customization Since existing BAS are operated centrally by building managers they don t cater to the particular needs of every user which are also dependent of his localization in the building For example users with windows in their rooms will have different luminous and thermal requirements than of those who don t e Expensive installation Another problem with BAS is the cost of devices and their installation or upgrade Since bus networks are usually used the cost of wiring and dedicated conduits becomes significant in large buildings Hence the number of sensors and actuators is usually limited to the automation of building zones rather than offices 1 3 Proposed Solution This thesis presents a solution for the lack of affordable personalized office management and automation systems designed to enhance the occupants comfort and minimize energy footprint at the building scale We designed a system capable of controlling the building s main energy demanding equipment such as lighting cooling and heating systems In order to achieve maximum energy efficiency the load of these systems will be adjusted according to the occupancy level and the users needs With the constant growth of the computational power of embedded systems it is now affordable to build a network of devices that can deal with these problems All the benefits of a BAS ca
13. be used in conjunction with B A T M A N or IEEE 802 115 to form a WMN The used wireless card shown in Figure 4 2 is an SMC EZ Connect YN 150 Mbps N Wireless USB Adapter Model SMCWUSBS N3 This card was chosen because of its Ralink RT2870 chipset as it has great driver support for the creation of WMN using the B A T M A N open source multi hop routing protocol Figure 4 2 SMC Wireless Card Model SMCUSBS N3 4 1 3 Sensors Our system will feature sensors capable of measuring the office ambient characteristics such as tem perature humidity luminous intensity and energy consumption Analog sensors were avoided because they need calibration and don t always have the best precision also they require an ADC for the reading of the values Unfortunately we couldn t find an digital current sensor and had to use an ADC for the reading of the energy consumption values Table 4 2 and Figure 4 3 show the specific models used and how they connect to the main board Sensor Vendor Model Connected Type via Luminosity Adafruit TSL2561 120 Temperature Humidity Sparkfun HTU21D 12C Current Flukso FLS01 50 ADC Table 4 2 Details of the sensors used TSL2561 photo resistors and photo diodes it incorporates both infrared and visible light sensors to better approx is a very popular inexpensive light sensor with very good device driver support Contrary to imate the response of the human eye It has
14. behavior in buildings energy efficiency 2 1 Building Automation BA Systems Building Automation Systems is a distributed control system composed of an intelligent network of electronic devices that are used to monitor and control the building s electronics lighting shading heat ing ventilation and air conditioning HVAC systems Figure 2 1 represents a typical BAS network Its most important targets are to maintain the building s climate within a comfortable range provide light ing based on an occupancy schedule monitor device failures and energy consumptions This kind of systems reduces building maintenance and energy costs Improvement in energy efficiency will also contribute to environmental protection For this reason policies and regulations sometimes mandate the use of this kind of systems Intelligent buildings require integration of a variety of Building Automation and Control BAC systems components that are usually made by different manufacturers The exchange of information among these devices is critical in order to obtain a successful operation of the building systems Historically competitive pressures and lack of standards forced manufacturers of building automation equipment to develop unique proprietary communication protocols Even within a single building automation function such as the control of an HVAC system can cause trouble If there is a need to expand or upgrade the control system the building owner has bee
15. building As a result classification of the user behavior was done in order categorize and optimize the overall building performance in the simulation scenario 22 Chapter 3 Architecture This chapter describes the architecture of PerOMAS a platform for personal office management and automation designed to offer comfort to every user and reduce the overall building energy use with minimum intervention The platform will also be used by the academic community to develop and validate alternative algorithms that maximize user comfort and or building energy efficiency This chapter is divided in four sections Section 3 1 starts by defining the requirements of the system that will lead the design of our architecture In Section 3 2 the architecture of the system is described in depth Finally section 3 3 and 3 4 present a brief overview of the hardware and software architectures 3 1 System Requirements Our system targets buildings with an increased number of individual offices which is the case of the research departments at IST campus Taguspark Subsections 3 1 1 and 3 1 2 describe and analyze a survey done to a subset of occupants at this location This helped to characterize them and establish a baseline of their behavior and comfort needs In order to choose the appropriate architecture in terms of performance functionality extensibility and comfort the system must satisfy the following set of requirements e Scalable Using IS
16. do O AE A ee 18 2 3 3 Vision based 2 a a a aaa aaa a D 18 vii DB WIFI erm A nn am be an ne an we q voa 18 2 3 5 Bluetooth oo 19 2 3 6 SUMMARY NN 19 2 4 Human Behavior ssa EX A A P Ro E aa a AA Brey 20 Architecture 23 3 1 System Requirements 0000 hs 23 3 1 Survey Description 44 4 4 du d xa dudas reed 24 3 1 2 Survey Analysis a 24 3 2 Architecture Overview 0 sss ns 25 3 2 1 The Assistant x 44 wwe 24 44 o uet godes RE OE LO Mus oo oe ux 25 32 22 The Gateway ies seu E SA SIR SOR E Rex UE ern ee DR RR 26 3 23 ThE Core 1 2 2 2 ur E arro RUE eee dre rent e eter dodo Bhabha ELT 27 3 3 Hardware Architecture o ee 27 3 3 1 Communication Protocols 2l 27 3 3 2 ConinectiVIty usus LEURS EA SS EU ENS e RR A rg 28 3 3 3 Information Input and Data Feedback e 28 3 4 Software Architecture nn 29 3 4 1 Communication abstraction layer 2 2 0 0 llle 29 3 4 2 Hardware abstraction layer o e e e 30 3 4 3 Automation layer ll llle 30 3 4 4 Interface abstraction layer o a e ee 31 3 45 JUserinterfaCes S a aa xx Ven A ta a 31 3 5 Deployment at IST Taguspark 22e 32 3 6 S mmary au 4 odd ai E E AAA ae ee ba ie E ER dida 33 Implementation 35 41 Hardware Architecture sara a a a aa a ala a a a a AE a a a e a A A A 35 4 1 1 Single Board Computer aao 0000 ee 35
17. dynamic range sensitivity that ranges from 0 1 to 40 000 Lux and connects to the main board via the I2C bus The sensor has an operating temperature range 37 TSL 2561 eso SENSOR a TSL2561 Luminosity sensor b HTU21D Temperature Humidity sensor c FLS01 50 Current sensor Figure 4 3 Sensors used for measuring ambient characteristics and energy consumption from 30 C to 80 C It will help to provide information about the abundance of light in every room which later will be used to control the lighting configuration in the room HTU21D is a low cost low power highly accurate digital relative humidity and temperature sensor that uses the I2C bus The temperature sensor has a typical accuracy of 0 3 C with a resolution of 14 bits and an operating range from 40 C to 4 125 C It also contains a humidity sensor with a typical accuracy of 2 resolution of 12 bits and an operating range from 0 to 100 These sensors will provide information about the thermal comfort in every room which is the main reference for the control of the HVAC system FLS01 50 is split core current clamp for current measurement that functions on the principle of induc tion Depending on the number of coils in the clamp it will produce an analog voltage output which an ADC will translate into digital values This model has a maximum rated measurement current of 50 amps which is sufficient for residential or office loads For measu
18. e Leaving the lights on when daylight illumination is sufficient These are some examples of user behaviors that cause significant energy waste and can be solved through user feedback analysis and detection based automation However in order to detect these behaviors sensors that can measure energy consumption and perform user detection must be present in every room At the moment buildings with rooms equipped as such are almost non existent 1 2 Problem Statement The major goal of this thesis is to reduce the overall energy use of a building without impacting its users comfort In order to achieve this a list of problems must be analyzed and resolved e User Behavior and Neglect These are the main variables responsible for the different energy consumption patterns in buildings It is difficult to change user habits and the amount of informa tion they have available or are willing to use in their decision making process is limited Limited Flexibility Currently installed BACS are not open source and require specialized per sonnel for installation and configuration Because of that they are limited to pre installed functions and have the risk of easily becoming outdated Limited Efficiency Current solutions are unable to predict the future demand on a specific sys tem or service Thus their duty cycle is approximated which could lead to big energy loses or user comfort E g a chiller may operate all night to store a large
19. fields provided by the WTForms that reports any errors in the fields and displays them in red The last field is the registration key which is an always changing key provided by the LCD menu shown in Figure 4 13 f When logged out the system only shows the ambient sensors readings Figure 4 15 asking for the log in credentials if trying to access any other menu After logging in the control of the lighting and HVAC systems is revealed in the main menu The access to the configuration menu and graphs is also unlocked Figure 4 16 shows the dashboard and 1Shttp www tornadoweb org 14http flask pocoo org 5http jinja pocoo org tehttp Awtforms simplecodes com 17http getbootstrap com 50 the simple controls used for managing the lighting and HVAC systems of the office as well as sensor data information When the manual control of the HVAC system is selected its manual controls shows up on the automation menu Figure 4 17 The graph representation of sensor data presented in Figure 4 18 was achieved using the Dygraph 18 JavaScript library It offers a responsive and precise visualization of historic data with zoom and aliasing functions to the plotted values Figure 4 19 shows the menu used for selecting the ID token which is used to detect the user pres ence Still in Figure 4 19 we can observe the interface for manipulation of the user defined events On the bottom of the figure the triggered actions can be created from a
20. files of user actions and interactions with the system during a time span of one week They test will consist in observing the sensor readings behavior in function of user interaction with the system and their presence in the office 5 2 4 Conflicted Preferences In order to test the operation of the automatic conflict resolution protocol described in Section 4 2 5 a series of measurements will be used to determine the effect of the algorithm The measurements will help to determine if the applied setting provide all the members of an office with different ambient 58 preferences The test will make use of the sensor readings of the Assistant node and log all the sensor readings for posterior analysis The test will consist in determining the effect of multiple users with different preferences in the same office and in the same time interval First during the day when the HVAC system is functioning one user with predefined preferences will be present in the office After some time another user with different thermal preferences must enter the office Finally the first user must leave the office leaving the second user alone 5 3 Test Results 5 3 1 Energy Consumption Results As mentioned before two devices with 2000W and 1500W ratings were tested for a period of at least five minutes As shown in Figure 5 2 the first spike that begins at around 5 53 AM jumped from a value of 184 6W to 2171 7W which results in a jump of 1987 1W a
21. has a 3300 F and a 100 nF capacitors for each of the 5 Volt and the 3 3 Volt rails to smooth the power delivery and diminish ripple 41 CO SU ou vn scans so 00 Asta ry 2 a Front b Back Figure 4 8 Developed connection and power board 4 1 8 Summary The final iteration of the hardware architecture is resumed in Figure 4 9 which shows the connection protocols between the Raspberry Pi SBC and the sensors actuators and peripherals Figure 4 10 shows a close up preview of the internals of an Assistant node installed in one of the offices Since this is a prototype node it s size is quite big for the intended application but could be much smaller if integrated in a single SBC Every node is worth around 150 in parts lts mass production would lower the production costs making it more affordable and cost effective Office Controller RaspberryPi E 2 X KA q Power ADC IL nd Relays i 2 A N S e lt Y b ES kw SS 7 S HVAC 7 u Humidity Temperature Lux Current o I a A Sensor Sensor Sensor Sensor IH Figure 4 9 Electrical wiring of the sensors actuators and peripherals 4 2 Software Architecture 4 2 1 OS As mentioned in Section 4 1 1 when the main board was being elected the OS plays a major role in the selection process of the SBC Itis as important as the hardware itself because it defines the platform used to access the hardware If
22. is presented Finally Section 5 3 presents the results of the tests 5 1 Tests Scenario Allthe tests were conducted in real scenarios inside a building zone ofthe IST Taguspark campus They were executed using three fully functional Assistant nodes composed with the hardware described in Section 4 1 one of which was also functioning as a Gateway as explained in Section 3 4 Figure 5 1 shows their approximate location in the building zone and the probable communication paths within the wireless mesh network The Gateway node also worked as a bridge between the Assistants and the automation Virtual LAN VLAN to which it was connected using an Ethernet connection Allthe nodes were powered using 5 V 2100 mA switching power supply connected to the nearest power plugs User detection and identification was performed using BT capable mobile phones 5 2 Tests Description 5 2 1 Energy Consumption In order to test the accuracy of the current sensor it was tested against two electric devices a heater rated at 2000W and a heat gun rated at 1500W These devices were chosen because contrary to computers which have switching power supplies they offer a constant power consumption over time and their power consumption is much higher than the load created by other electronic devices in the office such as monitors and computers The test consists in observing the energy consumption variation by using the current sensor which is attached to the input of
23. labs classrooms and common areas This university is equipped with a basic BAS that has a scheduler based control which is unaware of the building occupancy or user location The scheduler is programmed to maximize energy savings i e the distributed heating system starts working at 8 AM and remains operational until 9 PM the centralized cooling system works from 8 AM to 6 PM and the corridor lighting is turned on from 5 PM until 7 AM Some lights are on all the time It is easily noted that this solution does not provide the best results in terms of energy efficiency regarding lighting and HVAC For example during exam periods and projects deadlines the occupants of the university tend to stay up until very late hours In such situations this kind of system does not allow building occupants to adjust the system to their needs being unable to provide the necessary heating or cooling comfort due to the limited operation time frame This situation is more noticeable during winter and summer when the HVAC system are constantly required Also during vacation periods the system operates as if the building is being fully used There are also occupant related problems which frequently happen due to negligence such as Setting higher values on the thermostat than actually necessary e Forgetting to turn off the HVAC system upon leaving e Leaving the door open when heating cooling is active e Leaving the lights on needlessly or forget to turn them off
24. list of pre selected actions with optional user arguments The middle menu is used to define triggers such as time intervals and the user presence in the office Finally the menu below the token ID selection is used to associate triggers to actions In order for the action to be executed all the triggers must be valid The rest of the menus are used for debugging of the WEB UI 8http dygraphs com 51 G Dashboard MGrapn HiSetings A Gateway Admin 4 Register Artur Register Form 9 sername Field must be between 8 and 100 characters long Passwords must match A password 8 confirm password Field must be at least 4 characters long P assistant key Figure 4 14 Registration Menu Dashboard f Graph HiSettings A Gateway O Admin Register MWLogIn Ambient Temperature Relative Humidity 23 8 C 65 6 364 Lux 186 8 Watts Last Update 19 43 39 Figure 4 15 Automation Menu when logged off 52 Dashboard Graph HiSetings Gateway Admin Register WArur Ambient Temperature Relative Humidity 24 7 C 52 5 370 Lux 192 5 Watts AC Mode Lights ES Manual Light Bulb x1 9 Light Bulb x2 9 Last Update Presence Username Device Artur 40 B0 FA 3D 5F 08 Figure 4 16 Automation Menu Ambient Temperature Relative Humidity 23 8 C 65 2 364 Lux 183 4 Watts Last U
25. listed examples represent some actions that are neglected by the users and cause unnecessary energy consumption which could be avoided with our system e Automatically turn off artificial lighting when user presence is not detected e Automatically turn off artificial lighting when natural lighting is sufficient e Automatically turn off HVAC when user presence is not detected e Automatically turn on or off any other system service depending on occupancy levels in rooms building zone or building The system will also include the option to support and test multiple calibration and management algorithms which could provide better results in terms of energy efficiency and or user comfort Based on the collected information from sensors energy consumption user presence and their actions statistic charts may be created for easy interpretation of this data to users and building managers The devices will be arranged in a hierarchical architecture where the root device will aggregate information regarding the entire building that could be used to determine the building s total heating cooling and energy needs The intermediate devices will gather information regarding a part of the building such as floor levels or building zones Finally the devices in every room represent the leaves of the tree that generate information used by the upper levels This solution will help adjust the load of every intermediate system service to that required by the occupan
26. meters Using a BT 4 0 capable USB dongle shown in Figure 4 6 b either of the beacons can be captured and an approximate distance of the emitter determined based on beacon s Signal to Noise Ratio SNR x 2 i VU a Qualcomm s Gimbal Proxmity Beacon b Bluetooth 4 0 Adapter Figure 4 6 Bluetooth Low Energy capable emitter and detector Figure 4 6 b shows the used LM506 BT 4 0 Dual Mode SMART Ready BLE USB Adapter Since it is backwards compatible it is capable to communicate with both traditional BT Classic 2 0 2 1 and 3 0 standards along with the new BLE standard It is a Class 1 adapter that can reach a maximum distance of 110 meters in open space which is more than enough for the intended application In the Building In order to detect the user presence in the building the Wi Fi DS of the building is used Using cell based positioning we can determine without the need of any additional equipment an approximate position of a device associated to an AP This information is extracted using SNMP calls to the APs 4 1 6 Data Input and Feedback As described in Section 3 3 3 a system override may be needed in some situations For example when the occupant forgot the ID token when registering a new user or simply to control the lighting and give important information to the user as an ECI For this purpose besides the WEB UI a second physical Ul is needed Two types of displays with different input methods we
27. o 5 4 Esse conflicto causa lhe desconforto Se respondeu N o quest o 5 3 ignore esta quest o Sim N o 6 Com que frequ ncia costuma desligar as luzes quando sai de um gabinete ou sala considerando que a sala ou gabinete ir ficar sem nenhum ocupante Nunca Raramente Frequentemente Sempre 7 Com que frequ ncia costumar desligar o sistema de climatiza o quando sai de um gabinete ou sala considerando que a sala ou gabinete ir ficar sem nenhum ocupante Nunca Raramente Frequentemente Sempre 67 8 Quantas vezes por dia costuma regular o sistema de climatiza o 9 De inverno qual a temperatura ambiente que costuma usar no sistema de climatiza o indique o valor em graus Celsius caso seja a temperatura m xima ou a m nima indique MAX ou MIN respectivamente 10 De ver o qual a temperatura ambiente que costuma usar no sistema de climatiza o indique o valor em graus Celsius caso seja a temperatura m xima ou a m nima indique MAX ou MIN respectivamente 11 Costuma trabalhar durante a noite nas instala es do IST Taguspark considerando que a partir das 20 h noite Sim N o 11 1 Durante a noite como classifica o sistema de climatiza o Se respondeu N o quest o 11 ignore esta quest o Muito Mau Mau Razo vel Bom Muito Bom Excelente Outro 12 Durante o dia como classifica o sistema de climatiza o Muito Mau Mau Razo
28. passwords 56 which protects against lookup tables reverse lookup tables and rainbow tables attacks to the database There are two types of accounts the Normal account and the Administrator account The Normal http tools ietf org html rfc2898 47 accounts are user accounts that are created through the registration process They only have access to the control of the Assistant node of the office in which they are registered On the other hand the Administrator account comes pre installed in all the nodes and has total access to all the nodes It is used to program global energy efficiency events and system wide configurations The Scheduler module is used for triggering tasks at a specific point in time or at repetitive intervals Our implementation adds the possibility to define a maximum number of times a task can be executed This is useful for one time routine tasks that must be executed once and then forgotten The Scheduler module is also run by a separate execution thread In order to reduce its complexity the scheduler maintains a pool of executable tasks that it validates for possible execution in a round robin model When a task is validated for execution the Scheduler runs it Each task contains all the necessary information for its execution including variables and pointers to callable functions A list of internal tasks are always in execution Since not all sensor readings need to be stored there are tasks dedicated
29. shown in Figure 5 5 has an inverse effect when comparing with the temperature graph Every time an occupant enters the office there is a certain build up of humidity but afterwards the humidity decreases showing the effect of the HVAC system operation Finally Figure 5 6 shows the level of luminosity in the office during the day Since the lights in the office have a much higher incidence over the sensor it can be noted by the readings when the office lights are on or off During the day it registers small values which seem to be sufficient for the occupants of the office During the night whenever the occupants are present we can observe an expressive amount of luminosity demonstrating that the lights are on Temperature C Muedmao 5 ne f l 0 090ct 02 00 0400 0600 08 00 10 00 1200 1400 1600 1800 2000 2200 100ct Figure 5 4 Temperature Readings 5 3 4 Conflicted Preferences Results In order to test the operation of the automatic conflict resolution protocol mentioned before a specific set of actions must be executed in order Figure 5 7 shows the temperature variation in the office during a period of 24 hours The red line represents the temperature and the green line shows the time intervals when the office is occupied The green line also shows a sequence of markers which represent the following set of events 61 E o nm E ke P 1 E 5 B T lt 0200 0400 0600 0800 1000 1200 1400 1600 1800
30. slow increase in temperature 62 Temperature C Auedn o 02 00 04 00 06 00 08 00 10 00 12 00 14 00 16 00 18 00 20 00 22 00 Figure 5 7 Adjustable temperature to the present occupant 5 4 Summary In this chapter the tests done to assure the system s behavior were detailed It was concluded that the system operation followed the predicted guidelines and performed well The user detection and identification was proven to work without faults and was successfully used for the automation inside the office The tested sensors showed good accuracy and provided useful information to the user 63 64 Chapter 6 Conclusions 6 1 Summary In this document we present a system that has the objective of offering better comfort to the users of offices as well as the minimization of the overall energy consumption of the building In order to develop the solution for the problem we started by analyzing Building Automation stan dards available on the market Then we explored the wireless communication systems to see if we can reduce costs and make the system easily deployable using off the shelf materials A list of problems were identified regarding the user behavior in buildings and how they impacted its energy efficiency The limited flexibility customization and efficiency of the current solutions were identified and used as a base during the development of the PerOMAS architecture For a full automation of the system user dete
31. support user configurable actions to be triggered by a scheduler or sensor values e Flexible It must also be easily programmed to enforce multiple energy efficiency algorithms 3 1 1 Survey Description A survey was organized to characterize the comfort preferences of the users at IST Taguspark The initial data was collected from December 25 2013 until January 5 2014 via a Web based form The main distribution vector for the link to the form was via email to teachers staff and students of the IST Taguspark building Distribution was also done via social networks but only to restricted groups of users that are present at IST Taguspark The form contained 20 items with multiple response formats The questionnaire started with a char acterization of the user and then assessed behavioral intentions and practices relating to energy con sumption at IST Taguspark Other questions were related to user comfort in situations where multiple users share an office There was also questions regarding the number of mobile devices per user and how many ofthem were equipped with Wi Fi and or BT technology The complete survey in Portuguese is available in appendix A 3 1 2 Survey Analysis All data were based on the replies from 69 users The survey showed that all the users have at least one mobile equipment with an average of 2 1 devices person 98 of which were equipped with Wi Fi and 96 with BT technology Of all the users 47 have acces
32. the electrical cable that delivers power to the office s power plugs The test must run for at least five minutes in order to determine the power consumption of the devices and filter the background noise created by other equipment 57 LAI Office Office Office 20 internet Figure 5 1 Test Location 5 2 2 User Detection In order to test the reaction time of detection of user presence in the office a series of measurements were performed The test consists in observing the time the Assistant takes to detect the user s pres ence with the user being identified by its BT capable mobile devices The measurements will be per formed with the BT mobile device near the Assistant in order to increase the SNR of the signal and avoid miss readings The device used will be a LG Nexus 4 with BT support up to version 4 0 Due to the rapid reaction of the detection system a chronometer will be used to determine the reaction time The test will result in at least a set of 25 measurements in order to determine a meaningful average of the reaction time of the system 5 2 3 Temperature Humidity and Luminosity To test the Temperature Humidity and Luminosity sensors and their capabilities a series of measure ments will be executed The tests will be performed using the sensors described in Section 4 1 3 which are installed on an Assistant node The Assistants will store sensor readings as well as log
33. the scene and the moving pixels in the images 40 Most buildings already have surveillance cameras which can reduce the cost of their deployment On the other hand video processing is computationally very demanding that can increase the cost of this type of technology Another problem is the difficult calibration and the infrastructure needed to connect to this kind of systems which can also be expensive 2 3 4 Wi Fi Nowadays the Wi Fi technology also known as IEEE 802 11 standard is widely used especially in office buildings and can be found in almost all modern devices such as laptops smart phones and even printers Occupancy detection using the Wi Fi infrastructure is easy to implement and can be economical because it does not require the installation of additional equipment There are two ways that can be used to identify user occupancy and position using Wi Fi technology Either using cell based positioning or using the Received Signal Strength RSS In some cases triangu lation based on RSS of at least three APs can be used to infer the physical location of a STA 41 When this method is used indoors reflection and multipath problems arise and can heavily impact accuracy Figure 2 3 represents an example of cell based positioning implemented by the author of this doc ument at IST Taguspark The data from the APs and from the Remote Authentication Dial In User Service RADIUS server can be merged in order to identify the occ
34. was discovered that habit emerges as the most important barrier to changing behavior Data indicated a relation between the occupant s behavior their energy consumption and motivation in engaging in energy saving actions This link shows the http www isasensing com Vis o Geral Figure 2 4 Interface of a ECI used by Cloggy 21 importance of breaking habits in order to change energy consumptions patterns Habits are normally difficult to change Because of this when energy efficient incentives are unsuccessful a better approach that could change the occupant habits is to change the situation 3 When a context change disturbs an individual s habits new behavior is more likely to be consciously considered and consequently changed For example moving house or work place could be considered such a change in context giving landlords or real estate agencies the opportunity to help the new occupants to engage in energy savings habits e g by doing a tour of the building discussing its HVAC operation and maintenance Studies about building energy conservation often overestimate potential energy savings because the impact of consumer behavior is not taken into account 45 For example 1 found that the use of a thermostat for temperature control increased energy use The study determined a correlation between the presence of a thermostat and the temperature setting during the night This behavior could be explained by the fact t
35. 0 3 March 2005 343 351 49 Vringer K Aalbers T Blok K Household energy requirement and value patterns Energy Policy 35 1 January 2007 553 566 50 Abrahamse W Steg L Vlek C Rothengatter T A review of intervention studies aimed at household energy conservation Journal of Environmental Psychology 25 3 September 2005 273 291 51 Wood G Newborough M Dynamic energy consumption indicators for domestic appliances environment behaviour and design Energy and Buildings 35 8 September 2003 821 841 52 Froehlich J Findlater L Landay J The design of eco feedback technology In Proceedings of the SIGCHI Conference on Human Factors in Computing Systems CHI 10 New York NY USA ACM 2010 1999 2008 53 Linden A L Carlsson Kanyama A Eriksson B Efficient and inefficient aspects of residential energy behaviour What are the policy instruments for change Energy Policy 34 14 September 2006 1918 1927 72 54 NXP Semiconductors UM10204 I2C bus specification and user manual 2007 55 Motorola Inc SPI Block Guide V03 06 2003 56 Turan M S Barker E B Burr W E Chen L Sp 800 132 recommendation for password based key derivation Part 1 Storage applications Technical report National Institute of Standards and Technology Gaithersburg MD United States 2010 73 74
36. 02 11ac revision 26 It can also use the optional Request to Send Clear to Send RTS CTS mechanism to reduce frame collisions between nodes that cannot sense each other but cause collisions at the receiver 27 Enhanced Distributed Channel Access EDCA is used to provide differentiated and distributed traffic prioritization with eight different priority levels The most basic entity of IEEE 802 11 WLAN is a STA which represents a device with Wi Fi capa bilities such as a Smart phone or Laptop An AP is a STA with extended capabilities that is the central device of a WLAN which is usually connected to a wired network STAs associate and authenticate with the AP to get access to the network forming a star topology This topology is called an infrastructure Basic Service Set BSS STAs could also connect between themselves using the ad hoc mode to form an Independent Basic Service Set IBSS Figure 2 2 As depicted in the Figure 2 2 because of the EIRP limits imposed by the EU 100 mW and attenu ation caused by the radio propagation the range of a single AP is limited Furthermore multiple BSSs could be interconnected using a Distribution System DS to form a Extended Service Set ESS net work of arbitrary size and complexity The IEEE 802 11 standard can also be used to create multi hop networks Snttp www bluegiga com en US products bluetooth classic modules wt41 long range bluetooth module Class Maximum permit
37. 12 MB 512 MB 1 GB 1 GB 2KB Flash SD Card 2 GB SD Card 4 GB 32 KB GPIO 26 65 56 96 14 ADC 7 12 bit 6 10 bit USB 2 1 3 2 Ethernet 10 100 10 100 10 100 10 100 12C Yes Yes Yes Yes Yes SPI Yes Yes No Yes Yes Various Linux Various Linux OS Support BSD RISC OS BSD Symbian Linux Ubuntu Various Linux Windows CE Size mm 86 x 54 87 x 54 114 3 x 101 6 100 x 60 68 6 x 53 3 Cost 35 45 162 49 27 Table 4 1 The main differences between the most popular SBCs and single board micro controllers Figure 4 1 Raspberry Pi Model B 4 1 2 Wireless and Wired Communication As stated previously in Section 3 3 2 a wired and or wireless module must be used for communication between nodes In order to adapt the system to a bigger area and ensure its extendibility a mesh network was used to interconnect the assistants and the gateway nodes The gateways and the core node will also require an Ethernet connection which the Raspberry Pi Model B SBC already has included 36 The Ethernet interface is necessary because the gateways may be located far away from each other or in locations where wireless propagation is poor For the mesh network to be created a range of radio modules exist but since the IEEE 802 15 4 ZigBee has a maximum data rate of 250 kbit s it makes it unusable for transmitting data rich web content as intended for the WEB UI described in Section 3 4 This leaves the IEEE 802 11 Wi Fi interface to
38. 4 1 2 Wireless and Wired Communication lll 36 AS Sen SOLS NN 37 4 1 4 Actuators 3 205 010 an Roy odds emm RR AA De ie cm ee e LS 39 4 1 5 User Detection o a 39 4 1 6 Data Input and Feedback leen 40 4 1 7 Major Problems and their Solution 0 oo e 41 ABS SUMMA AA Rape A ad uias e BON LS e 42 4 2 Software Architecture ee 42 AD AOS A A e cda q ca cat a a pa ee a 42 4 2 2 Programming Languages a a 43 4 2 3 Auxiliary Programs and Libraries 0 o e ee 44 4 2 4 Network Configuration aoaaa 4 2 5 Software Architecture Implementation 4 3 Deployment at IST Taguspark 2 2 2 2e 4 4 SUMMARY au a araara a MED E A S a re xs 5 Evaluation 5 1 Tests Scenario Write A dad a BED eg 5 2 Tests Description o 5 2 1 Energy Consumption 22h 5 2 2 UserDetection sa kB A momo vom wy Goose cw q ox 5 2 3 Temperature Humidity and Luminosity 5 2 4 Conflicted Preferences 2222 5 3 Test RESURS o s a gs mm A EVER E Gee we E wo 5 3 1 Energy Consumption Results 2n 5 3 2 User Detection Results llle 5 3 8 Temperature Humidity and Luminosity Results 5 3 4 Conflicted Preferences Results 5 4 SUMMARY DEDO ne deua tate Are Fore Ys ac qom ER os 6 Conclusions 6 1 SUMMA c uud OSEE Rue ea o de de de de e open ts 6 2 Achievemi ntlS s d doo oA obo ux or bor a stad ebore
39. System Por forma a recolher o m ximo de informa o com o objectivo de tornar este sistema o mais til poss vel para eventuais utilizadores pedimos que responda a este question rio Os dados recolhidos ser o apenas usados para os fins de optimiza o do sistema de climatiza o e ilumina o do IST Taguspark estando garantida a sua confidencialidade Obrigado pela sua colabora o 1 Sexo Feminino Masculino 2 Idade menos de 11 11 19 20 30 31 50 mais de 51 3 Indique a sua fun o no IST Taguspark Aluno Docente Funcionario Outro 4 Possui dispositivos m veis ex smarthphones tablet s computadores Sim N o 4 1 Quantos Se respondeu N o quest o 4 ignore esta quest o 4 2 Quantos desses dispositivos possuem tecnologia Bluetooth Se respondeu N o quest o 4 ignore esta quest o 4 3 Quantos desses dispositivos possuem tecnologia Wi Fi Se respondeu N o quest o 4 ignore esta quest o 5 Possui gabinete no IST Taguspark Sim N o 5 1 Partilha o gabinete com outros colegas Se respondeu N o quest o 5 ignore esta quest o Sim N o 5 2 Com quantas pessoas partilha o gabinete Se respondeu N o quest o 5 1 ignore esta quest o 5 3 As suas prefer ncias quanto ao sistema de climatiza o costumam entrar em conflito com as dos seus colegas de gabinete Se respondeu N o quest o 5 2 ignore esta quest o Sim N
40. T Taguspark as an example building we are looking at roughly 700 equipped offices With such a large number of offices the system must be very scalable and offer rapid deployment of new nodes Cable wiring introduce costs and as a consequence it must be kept to a minimum e Isolation The control and automation of the offices must be independent and work regardless the state of the rest of the system e User aware It must be possible to identify the user location with medium low precision inside the building and with high certainty if the occupant is in the office e Load aware The system must be able to adjust subsystems services such as HVAC and lighting in an energy efficient manner that satisfies the needed capacity at the office department and 23 building levels e Multiuser It must be capable of finding and maintaining multiple user preferences based on their interaction with the system which also needs to be minimal In case multiple occupants with conflicting preferences find themselves in the same office the system must be capable in adjusting the ambient settings in order to minimize their discomfort e Evolving The system must also be auto adjustable to weather change and behavioral changes e User friendly The system must allow individual remote configuration of each of the components of the system via an easily available tool such as a web browser that could even be used from a smart phone It must also
41. TECNICO LISBOA PerOMAS Personal Office Management and Automation System Artur Balanuta Thesis to obtain the Master of Science Degree in Telecommunications and Informatics Engineering Supervisors Prof Dr Ricardo Lopes Pereira Prof Dr Carlos Santos Silva Examination Committee Chairperson Prof Dr Paulo Jorge Ferreira Supervisor Prof Dr Ricardo Lopes Pereira Members of the Committee Prof Dr Jos Carlos Monteiro October 2014 Abstract The problem of creating more sustainable energy consumption habits has recently received a lot of attention from the research community Systems capable of reducing energy consumption are needed in order to reduce costs for companies or to avoid environmental destruction In this scope this thesis proposes a system to address the energy consumption problem and inadequate habits of people in office buildings It s a highly flexible office management system that can scale from an individual node in an office to the whole building The proposed system differs from traditional centralized Building Automation and Control Systems BACS by offering a distributed architecture with nodes deployed in every office This provides a low granularity of control enabling building wide policies to be enforced while providing users with a local interface for controlling their comfort level The goal is to reduce global building energy consumption without significantly affecting the users comfort level
42. This document surveys the current state of the art in building automation wireless communication and occupancy detection systems Our proposal is presented in detail and validated in the context of an academic institution more specifically at IST Taguspark Keywords Human Behavior Energy Efficiency BAS Occupancy Detection Wireless Mesh Networks Sensors Resumo O problema de criar mais h bitos de consumos energ ticos sustent veis recentemente tem recebido muita aten o da comunidade investigadora Sistemas capazes de reduzir o consumo energ tico s o precisos para reduzir custos para as empresas ou para evitar destrui o ambiental com este escopo que esta tese prop e um sistema que aborda o problema do consumo energ tico e h bitos de pessoas em pr dios de escrit rios um sistema de gest o de escrit rio altamente flex vel que pode escalar de um n individual em um escrit rio para todo o edif cio O sistema proposto difere do tradicional BACS centralizado oferecendo uma arquitetura distribu da com n s instalados em cada escrit rio Isso proporciona uma baixa granularidade de controlo permitindo que as pol ticas sejam aplicadas em todo o pr dio proporcionando aos utilizadores uma interface local para controlar o seu n vel de conforto O objetivo reduzir o consumo global de energia do edif cio sem afetar significativamente o n vel de conforto dos usu rios Este documento analisa o estado da arte atual em
43. Wireless and Mobile Commu nications 2009 346 351 42 Pei L Chen R Liu J Tenhunen T Kuusniemi H Chen Y Inquiry Based Bluetooth Indoor Positioning via RSSI Probability Distributions 2010 Second International Conference on Advances in Satellite and Space Communications 2010 151 156 43 Naya F Noma H Ohmura R Kogure K Bluetooth based indoor proximity sensing for nursing context awareness Wearable Computers 2005 Proceedings Ninth IEEE International Symposium on Oct 2005 212 213 44 Verplanken B Aarts H Habit Attitude and Planned Behaviour Is Habit an Empty Construct or an Interesting Case of Goal directed Automaticity European Review of Social Psychology 10 1 January 1999 101 134 45 Haas R Auer H Biermayr P The impact of consumer behavior on residential energy demand for space heating Energy and Buildings 27 2 April 1998 195 205 46 Hoes P Hensen J Loomans M de Vries B Bourgeois D User behavior in whole building simulation Energy and Buildings 41 3 March 2009 295 302 47 Jain R K Gulbinas R Taylor J E Culligan PJ Can social influence drive energy savings Detecting the impact of social influence on the energy consumption behavior of networked users exposed to normative eco feedback Energy and Buildings 66 November 2013 119 127 48 Liao Z Swainson M a L Dexter On the control of heating systems in the UK Building and Environment 4
44. act function that are used to normalize the interactions with the virtual devices Every virtual sensor and actuator then extends this class to implement their specific parameters communication libraries and data manipulation functions Each virtual sensor runs in a separate execution thread that is constantly updating its internal state This allows a parallel inquiry of the sensors and better use of the system resources As shown in Table 4 4 the polling interval depends mostly on type of sensor The polling interval was adjusted in function of the relevance of the information obtained by every update But these values may be also 45 limited by the hardware itself which is the case of the BT Office Presence sensor that takes around ten seconds to make a full scan The sensor readings are returned using Data Transfer Objects DTOs this ensures that every reading is processed and stored according to its type which is specified by the DTO Virtual devices such as the HVAC and lighting which are controlled by relays don t have to be constantly updated they only reflect the state of the hardware and contrary to the sensors that are ReadOnly devices also offer state changing functions that are applied to the physical actuators for the device Virtual Device Type Measurements second Temperature ReadOnly 1 2 Humidity ReadOnly 1 2 Current ReadOnly 60 Luminosity ReadOnly 1 Office Presence ReadOnly 1 10 Building Pres
45. and processing power which complicates the development of the software architecture described in Section 3 4 Every board supports a variety of different Operating Systems OSs This plays a major role since it will define the base for the software development and the tools available in each platform As described in Section 3 3 the board has to have a collection of I O ports that include GPIO I2C SPI and USB support The Pandaboard ES SBC other than the high cost lacks support of the SPI protocol that is used in a variety of sensors and peripherals This leaves the Raspberry Pi 1 the Cubieboard http www raspberrypi org 35 and the Beaglebone Black eligible to be used for the construction of the boards From the three the Raspberry Pi Model B SBC is the smallest the cheapest has two USB ports and it is available in large quantities at local stores It also has great support from sensor and peripheral vendors in term of device drivers which aids the development of the software Because of these aspects the Raspberry Pl Model B shown in Figure 4 1 will be used Raspberry Pi Beaglebone Pandaboard Arduino Name Model B Black ES pa eeead Uno Type Single board Single board Single board Single board Single board Computer Computer Computer Computer Microcontroller CPU ARM11 ARM Cortex A8 e ARM Cortex A8 ATmega328 CPU Speed 700 MHz 1 GHz 1 2 GHz 1 GHz 16 MHz RAM 5
46. automa o de pr dios sistemas de comunica o sem fios e taxa de ocupa o A nossa proposta apresentada em detalhe e avaliada no contexto de uma institui o acad mica mais especificamente no IST Taguspark Palavras chave Comportamento Humano Efici ncia Energ tica BAS Taxa de Ocupa o Redes Sem Fios em Malha Sensores vi Contents Abstract iii Resumo v List of Figures xii List of Tables xiii Acronyms XV 1 Introduction 1 1 1 Motivations 20 ad god ee atl wear 1 1 2 Problem Statement 222 lll ss 2 1 3 Proposed Solution llle 3 1 4 Thesis Contribution 2n 4 125 SHOUTS TS ach Earl Hoke qma x POP PE al DR Ap as Ses a B VES de 5 2 Related Work 7 2 1 Building Automation BA Systems llle 7 2 BAGS Ri 2 SS os ayes A ee ne a 8 24 2 LonWokS 2 3 2 2444 eo ee eee a eee bee ee aad KAP PES RS 10 263 JEIBIKNX sonic ea Pea a ae cee oh dede rom ae DN es 11 2 14 SUMMA ss Bata 12 2 2 Wireless Communication o 12 2 21 Infrared ss a wae ea ae ee De eo aS 13 2 2 2 Bluetooth BT sg sap a A a a a AAA AAA DS 13 2 2 3 Wireless fidelity Wi Fi 2 200000 ee ee ee 14 2 2 4 MEER B02 5 4 2 o ENA ene Ve teen chee UNUS ets Se or UP RR ada 15 2 2 5 SUMMARY 2 ale we AD Fe ade ie Ee E a e DP LOS 16 2 3 Occupancy Detection s aaa saaa nn 17 28 RRID ss Gar A ee ee Dan eg 17 2 3 2 DIR miss te tote do amp d Berenguer ae Rhee BASE et cw ae eed pote
47. ccess the WEB UI of the node and also shows the API key used to register new users The key is a security measure that prevents 49 users exterior to the offices from creating an account on the node of that office It is composed of a sequence of six random alphanumeric characters that changes every 45 seconds Who are you c User identification Api Key 172 20 41 191 5000 d Auxiliary Information e Temperature Dash Figure 4 13 Menu sequence of the LCD UI The WEB UI is the main UI used to control the system Its development was based on the Tornado Web Server Gateway Interface WSGI container and the Flask lightweight WEB application frame work written in Python which is based on the Jinja2 15 template engine This allowed for the use of a fast Python based WEB server that generates template based dynamic web pages In addition to Flask some of its extensions such as sessions cache and loginManager were also used For field definition and value verification the WTForms 9 Python library was used which can be seen working in Figure 4 14 We also enabled its Cross site Request Forgery CSRF protection mechanism in the Flask framework For the design of the pages we used the Bootstrap mobile front end framework which composes the base design of the web pages Before using the interface the user must be registered using the registration Form shown in Fig ure 4 14 The registration form uses intelligent
48. controllers operator workstations and application specific controllers BACnet WS is the most recent addiction to BACnet which describes the use of XML and Web Services WS for the integration of BACS with other enterprise systems BACnet WS is protocol neu tral thus can be also applied to non BACnet systems although a logic mapping between BACnet and BACnet WS is included in the standard 2 1 2 LonWorks The LonWorks system is a networking platform created to address the needs of control applications It consists of the LonTalk communication protocol created by Echelon Corp a controller the Neuron Chip 8 and a network management tool 9 5 The communication protocol LonTalk is a flexible field bus protocol which in 1999 was approved as an Electronic Industries Alliance EIA international communication standard ANSI EIA 709 1 9 The LonTalk standard was designed as a generic control network thus it supports many commu nication media and wiring topologies A number of communication channel profiles were defined over different media types such as TP Fiber Optics FO Coax Infrared IR Power Line PL and Radio Frequency RF From all of these the most used in BA is the free topology TP profile FT 10 78 1 kb s which allows physical segments with a maximum of 500 m Normally the TP 1250 1 25 Mb s profile is used in bus topology for the backbone of the network More recently there is a tendency to use IP tun neling mechan
49. couvalas A C Analysis and optimisation of link layer protocol in Gb s in frared links IET Communications 7 7 May 2013 652 662 20 Society 1 C IEEE Standard 802 15 1 IEEE standard for information technology telecommunica tions and information exchange between systems local and metropolitan area networks specific requirements Part 15 1 Wireless Medium Access Control MAC and Physical Layer PHY spec ifications for Wireless Personal Area Networks WPANSs Volume 2005 Society IEEE Computer 2005 21 Bluetooth S Bluetooth specification version 4 1 2013 22 Lee J S Su Y W Shen C C A comparative study of wireless protocols Bluetooth uwb zigbee and wi fi In Industrial Electronics Society 2007 IECON 2007 33rd Annual Conference of the IEEE Nov 2007 46 51 23 Ferro E Potorti F Bluetooth and Wi Fi wireless protocols a survey and a comparison Wireless Communications IEEE February 2005 12 26 24 Society 1 C IEEE Standard 802 11 2012 IEEE standard for information technology telecom munications and information exchange between systems local and metropolitan area networks specific requirements Part 11 Wireless LAN medium access control MAC and physical layer PHY specifications Volume 2012 Society IEEE Computer 2012 25 Hiertz G R Max S Zhao R Denteneer D Berlemann L Principles of IEEE 802 11s 2007 16th International Conference on Computer Communications an
50. ction and identifications techniques were tested using BT technology The architecture of the system was designed taking into account the possible future expansion of the IST Taguspark campus Some problems related to user behavior and neglect were mitigated by configuring the system to react to the user presence in the office Finally the solution was tested in real scenarios at IST Taguspark 6 2 Achievements Some of the main achievements of PerOMAS are the definition of flexible and expansible network hardware and software architectures Another contribution of PerOMAS is the offering of two intuitive user interfaces that ease the control and configuration of automation events The proposed hardware network and software architectures were instantiated in a fully functioning prototype A simple conflict resolving algorithm that manages the office comfort depending on the preferences of the present users was demonstrated A deployment of the system in a group of three Assistants and one Gateway was used to validate its operation A paper was submitted and accepted for publication in The 5th International Conference on Ambient 65 Systems Networks and Technologies ANT 2014 Another paper was accepted for publication and presented in Energy at IST Conference Iniciativa Energia Energy IST2014 6 3 Future Work Even though most the developed prototype is fully operational and the goals set in the beginning were fully achieved this
51. d Networks August 2007 1002 1007 26 Garber L Wi fi races into a faster future Computer March 2012 13 16 27 Bianchi G Performance analysis of the IEEE 802 11 distributed coordination function IEEE Journal on Selected Areas in Communications 18 3 March 2000 535 547 70 28 Camp J Knightly E The IEEE 802 11 s extended service set mesh networking standard Com munications Magazine IEEE August 2008 120 126 29 Chissungo E Blake E Le H Investigation into Batman adv Protocol Performance in an Indoor Mesh Potato Testbed 2011 Third International Conference on Intelligent Networking and Collabo rative Systems November 2011 8 13 30 Al Basset Almamou A Wrede R Kumar P Labiod H Schiller J Performance evaluation of routing protocols in a real world wsn Information Infrastructure Symposium 2009 GIIS 09 Global June 2009 1 5 31 Standard l Society 1 C IEEE Standard 802 15 4 IEEE standard for local and metropolitan area networks Part 15 4 Low rate wireless personal area networks LR WPANs Volume 2011 Society IEEE Computer 2011 32 Ma X Luo W The Analysis of 6LowPAN Technology 2008 IEEE Pacific Asia Workshop on Computational Intelligence and Industrial Application 3 December 2008 963 966 33 Gomez C Paradells J Wireless home automation networks A survey of architectures and technologies Communications Magazine IEEE June 2010 92 101 34 Mu
52. deus d 6 3 putute Work oi 4 iei uz o MENU doo m et ad ole la aim ore i chee tuere ce te te UE d odd A The survey Aa SUING s derrite elm Sa ee Bibliography 57 57 57 57 58 58 58 59 59 59 60 61 63 65 65 65 66 67 67 73 List of Figures 2 1 Example of an BAS system 0 ee 9 2 2 IBSS and ESS configurations of 802 11 networks 22 15 2 3 Blueprint of the library area at IST Taguspark with the position of some Access Points APs and the number of Stations STAs connected to each ofthem 19 2 4 Interface of a Energy Cost Indicator ECI used by Cloggy 21 3 1 Architecture Of the system 2 2 2 aaa 25 3 2 An example of RF communication paths within a department 26 3 3 The main communication protocols used between the main board and the peripherals 28 3 4 Abstraction Layers of the Application llle 29 3 5 Proposed architecture for IST Taguspark oo ee 32 4 1 Raspberry PiModelB nn a ee ee 36 4 2 SMC Wireless Card Model SMCUSBS NB 0 0 0 o a 37 4 3 Sensors used for measuring ambient characteristics and energy consumption 38 4 4 ADS1115 A 16 bit ADC with PGA LE nn e e 39 4 5 Relays used to control the HVAC and lighting oo 39 4 6 Bluetooth Low Energy capable emitter and detector 40 4 7 The two types of displays with different i
53. echelon com Shttp www loytec com nttp www knx org ElBnet IP Routing on the other hand is used as an IP backbone for interconnecting multiple EIB KNX networks Every device in the EIB KNX network gets an unique address which corresponds to the device position within the topological structure of the network zone line device This address is used for client server communication for initialization programming and diagnostic operations They also get a group address which is used for multicast communication between EIB KNX devices EIB KNX uses a shared variable model to represent the capabilities of each node The variables which are shared with the network are referred to as group objects which can be readable writable or both Group membership is defined individually for each group object of a node which can belong to multiple groups The EIB KNX makes use of the publisher subscriber model in order to disseminate changes of values in a group The specifications also defines a set of standard system components such as Bus Coupling Units BCUs BCUs are devices that implement the full network stack and the application environment They are used as a base for simple user applications and can provide a set of group objects The 10 Pin External Interface PEI on the BCUs can be configured to connect simple application modules such as sensors switches digital I O or a Analog to Digital Converter ADC More complex user applicat
54. ence ReadOnly 1 10 HVAC Readable Writable Lights Readable Writable Table 4 4 Type and pooling interval of the virtual devices Automation layer The automation layer is composed of a set of modules with distinct functions Their development and decisions option are described in detail in the next sections The Storage module is used to perform low level functions on the MySQL RDBMS It provides an API for persistent storage to the rest of the application and serves as an abstraction layer for the query language During the first stages of the application development the SQLite RDBMS was used Since the main application was developed in a threaded environment the use of the SQLite database resulted in slow performance because it locks the database during writes limitation parallel insertions and degrading performance The migration to MySQL removed this limitation and allowed for truly multi threaded access to the database The use of a relational database allows us to preform complex query s that return only the needed values at a cost of computational power As a result when dealing with data retrieval from large tables which is the case of displaying sensor logs the performance on the Raspberry Pi SBC shows its limi tations in form of delay which negatively impacts the responsiveness of the user interfaces A solution would be to perform tests with Not Only SQL NoSQL databases in order to verify possible performance
55. ery office 48 Complex events could be programmed by the Administrators taking into account historical data of sensor readings But for the purpose of this thesis only a set of simple events were developed in order to show the potential of the system e the HVAC system is turned off when no users are present in the office e automatically turn on the HVAC system when a occupant enters the office e when more than one user is present in the office the target temperature is set to the average preferred temperature of present group of people A user defined event could be programmed using the WEB UI For example they could automate the process of turning on the lighting when the user walks into the office and the time is between 7PM and 8AM Then turn them off again when they leave the office Interface abstraction layer and User Interfaces The General User Interface is an API developed in order to reduce code repetition in every type of UI It contains a set of function for manual control of the office systems user creation and preferences modification But since only two Uls were developed the shared functions are minimal This also happens because the two interfaces complement each other in terms of functionality which is described in the next sections The LCD UI is an instinctive UI used for quick override of the system The Ul was developed in Python using the pygame library which was mentioned before in section 4 2 3 It runs
56. essing power Contrary to IEEE 802 11s B A T M A N allows node mobility and can be implemented as routing protocol for Mobile Ad Hoc Networks MANETs 2 2 4 IEEE 802 15 4 IEEE 802 15 4 standard specifies the PHY layer and MAC for low rate WPANs which focus on low power low cost and short distance communication between devices 31 32 lt operates in the 868 MHz band in Europe 915 MHz band in North America and 2 4 GHz ISM band worldwide with data rates of 20 kb s 40 kb s and 250 kb s respectively In conjunction with Direct Sequence Spread Spectrum DSSS Binary Phase Shift Keying BPSK modulation is used in the first two bands with Orthogonal Quadrature Phase Shift Keying O QPSK in the 2 4 GHz ISM band For channel access in IEEE 802 15 4 two methods were defined beacon enabled and beaconless 33 In the beaconless mode the devices use the CSMA CA scheme In beacon enabled mode the devices assumes that there is a node acting as a coordinator which broadcasts beacons that synchro nize the network The time between coordinator beacons is divided into three periods First a contention access period is used with CSMA CA where the nodes compete for the medium Secondly a contention 15 free period where a node can transmit in an allocated guaranteed time slot And finally an inactive period in which the nodes may remain in sleep mode ZigBee and 6LOWPAN explained in the next sections are two of the best known open standards based o
57. g comfort preferences of multiple users and enforcement of energy efficient rules Functional Prototype Deployment of the system in a group of four nodes and one gateway Each node will serve an office and the gateway will control an service common to the four nodes corridor lighting e System Evaluation and Performance Evaluation of the user comfort and system energy effi ciency improvements Paper Submission A paper was submitted and accepted for publication in The 5th International Conference on Ambient Systems Networks and Technologies ANT 2014 1 5 Outline The rest of this document is organized as follows e Chapter 2 describes the previous work in the field e Chapter 3 describes the system requirements and the architecture of PerOMAS e The implementation of PerOMAS and the description of the technologies chosen are provided in chapter 4 e Chapter 5 describes the evaluation tests performed and the corresponding results e Chapter 6 summarizes the developed work and future work Chapter 2 Related Work In the next subsections we will explore the main related work used by this thesis Section 2 1 starts by examining the main Building Automation BA systems Following in the Sec tion 2 2 we explain the most used wireless communication technologies and their functionality Next Section 2 3 presents some tools and techniques used for occupancy detection Finally Section 2 4 describes the influence of human
58. hat in buildings equipped with a thermostat occupants are more aware of the interior temperature and therefore tend to turn it on more often than those without a thermostat Another study 53 found that for households living in dwellings where the energy bill is paid collec tively the average indoor temperature was higher by 2 C which also indicates a strong correlation to human behavior Consumer behavior as we have seen may significantly influence the level of energy demand by means of choosing the temperature levels ventilation rates thermostat settings and others These facts lead to the conclusion that energy savings achieved in practice due to energy conservation measures will be lower that those calculated in engineering conservation studies 45 1 45 found that building regulations on energy use have been very important in reducing energy consumptions in new buildings Because of this total energy use associated with buildings proprieties is decreasing making the role of the occupant even more important 46 takes a step further and includes human behavior as a variable in building performance simula tions The study showed that user behavior was one of the most important parameters to influence the end results of the building performance simulation The author concludes that the simple approach used nowadays for designing buildings using simulation are inadequate for buildings that have known close interaction of the user with the
59. he other hand the Gateways has both the subscribe module and the publisher module The subscribe module is used for listening on the different channels and combing the received values that after processing could be sent to higher level Gateways using the publisher module The Scheduler is responsible for executing repetitive tasks at regular time intervals or at fixed mo ments in time It is used to trigger pre programmed external tasks such as turning on the heating system at eight in the morning It is also used to trigger regular task internal to the program itself such as logging data from each sensor at variable time intervals for posterior analysis or sending it to a Gateway 3 4 4 Interface abstraction layer Since the system will support more than one user interface a synchronized state across all the interfaces is needed A interface abstraction layer will be used to deal with this problem It will contain a collection of functions common to all User Interfaces Uls and let them only focus on the presentation of the information avoiding conflicts between interfaces 3 4 5 User interfaces The WEB interface is the main UI for the control of the nodes In case of the Assistant node it will offer e Real time ambient sensors readings and their evolution over time in form of graphical charis e Manual control of the HVAC and lighting systems e User registration ID token association and ambient preference configuration e Crea
60. ible Also the lack of occupancy detection systems in buildings can lead to high energy loses especially in the form of illumination or heating by operating when unoccupied When user detection systems are used lighting shading and HVAC needs can be better determined and adjusted therefore increasing energy savings Buildings have been improving in energy efficiency Even though in the past decades materials with better thermal properties and more efficient systems have lowered overall energy consumption significant differences are still observable between similar buildings with occupants with different habits The energy consumption in this situation can vary up to three fold 1 This is why user behavior could strongly influence the energy consumption of a building 1 1 Motivation It is very difficult to adjust a Building Automation System BAS to provide comfort for every occupant and at the same time assure its energy efficient operation It is also difficult to motivate people to save energy especially in large buildings where the occupants are usually not billed for the energy consumption For these reasons occupants are likely to neglect the use of this kind of systems which heavily impacts energy consumption A specific example of these problems occurs at Instituto Superior T cnico IST Taguspark a univer sity campus with nearly two thousand students teachers and researchers working on several research and development
61. ing of messages In the future B A T M A N is expected to support WPA2 or a different wireless interface card with support for WPA may be used Corridor Lighting L SSA p i Internet w q 3 bx Assistant Assistant Automation EJ z E Assistant VLAN Gateway Assistant RO x q q d j A Assistant Assistant Router Building AC Core Gateway Zone Boiler Figure 4 11 The topology of the network 4 2 5 Software Architecture Implementation As described in Section 3 4 the main application was developed using a layered architecture In order to rapidly accommodate the use of new multi vendor peripherals and remote systems the communication and hardware abstraction layers were created Afterwards when an easy control of the virtual devices was achieved the main components of the automation layer were developed Finally the Interface abstraction layer and Uls were programmed Communication and Hardware abstraction layers Section 3 4 described that the control of the physical devices is abstracted using virtual devices In order to simplify and standardize the interaction with the virtual devices an abstract class was created that is implemented by every virtual device The abstract class is defined as a stateful object that reflects the present state of the physical device It can be treated as a ReadOnly object or a Readable and Writable object The abstract class also defines a set of abstr
62. ions which require more processing power than the simple microcomputer used in the BCUs can use the so called TP UART Integrated Circuit IC The IC implements the Physical PHY and data link layers of the OSI model and offers an Universal Asynchronous Receiver Transmitter UART interface to the Host controller that can be personalized for specific uses 13 15 2 1 4 Summary In the above examined BAS we observed that all the above platforms were designed for limited resource devices and low energy consumption in mind These factors limits the possibilities and capabilities of ev ery node The reason is that the automation control platform is usually on a centralized server commonly specified to as the Gateway which does all the processing These devices are normally composed of proprietary hardware designed with a single purpose and therefore are limited to certain specialized tasks Almost all of them require personalized software and or hardware to be configured Sometimes even specialized professionals are need in order to perform simple configuration tasks Some of them promise easy system integration with other platforms but in the end failed to do so for the complex tasks which typically forces the buyers to stay with a single vendor Another important aspect is the very high cost that these solutions could reach and are not properly explained by the cost of their individual electronic parts 2 2 Wireless Communication In the pas
63. is a very active research area and many ideas may be pursued Our system collects a significant amount of data which is of great interest to building managers These would benefit from an easy to use interface for the analysis of building data The same may be said for a way of defining global policies Many issues were found during the development of this thesis But many have not been further explored An important future work for this thesis would be to complete the initial planing of the system and have a building zone installed with Assistant nodes that would offer a complete control of the building zone During the development of our prototype some hardware related issues were found The touch screen panel have stoped responding in some occasions which was found to be caused by the high energy demand from the coil based relays These will to be replaced with solid state relays that use much less energy and will not cause voltage drops We have also experienced File System corruptions caused by occasional power cuts at IST s Taguspark building A battery backup power would prevent this ffom happening NoSQL databases may be tested to investigate the performance improvement in historic data analy sis and information retrieval Solutions to share user preferences between the nodes may be studied in order to ease user migra tion between offices 66 Appendix A The survey A 1 Survey PerOMAS Personal Office Management and Automation
64. isms LonWorks IP instead of the traditional TP 1250 backbone Both tunneling routers and fully IP based LonWorks IP nodes can be used Over the TP medium LonTalk uses the predictive p persistent Carrier Sense Multiple Access CSMA protocol 10 11 Allthe addressable space of a LonTalk network is referred as the domain The domains are identified by an ID that can be up to 48 bit long The domain can hold up to 255 subnets with a maximum of 127 nodes each which results in 32385 addressable nodes in the same domain Usually each physical channel is represented as a subnet but it is also possible for multiple physical channels to be linked into a subnet through bridges and repeaters On the other hand many subnets can co exist in the same physical segment Therefore routing is only performed between different subnets which usually are arranged in a tree hierarchy In case of domain routing a proxy node is needed in order to transfer the information at the application layer In every domain there can be up to 256 multicast groups Broadcasts messages can be addressed to the entire domain or to a specific subnet If needed a reliable transmission mode with end to end acknowledgments can be used for unicast and multicast messages In addition to unacknowledged Thttp www w3 org TR REC xm1 mode the unacknowledged repeated mode can be used which automatically repeats the transmission a programmed number of times The LonTalk application la
65. it 12C 54 Serial Peripheral Interface SPI 55 or simply by using the General Purpose Input Output GPIO pins In some cases sensors with analog output like current sensors may need an ADCs I2C and SPI are master slave protocols and because of that a single interface could be used to connect to hundreds of other devices On the other hand we may need to have multiple GPIO pins for connecting simple devices such as buttons and actuators Via the I2C or SPI buses GPIO expanders shown in Figure 3 3 may provide the needed extra pins to the main board 27 3 3 2 Connectivity Depending on the type of node the device must also have a wired and or wireless interfaces An Assistant node may only have a wireless interface for connecting to the Gateways but the least one Assistant must have both because it also acts as a bridge between the two media Wireless standards with mesh capabilities are preferred because they permit each node to act as an relay and expand the total network range lowering the deployment cost Nowadays a wide range of these modules can be found based on the IEEE 802 15 4 or 802 11 radios that could be connected via the I2C SPI or Universal Serial Bus USB buses to the main board as shown in Figure 3 3 3 3 3 Information Input and Data Feedback When the device is fully configured the user may not need to interact with it But sometimes a system override may be needed e g in case the user forgot the ID token o
66. layed to a gateway using the publish subscribe model Using this model the gateway can announce its interest in particular data Gateway Figure 3 1 Architecture of the system 25 to the assistants Then when any of this information changes the assistant will immediately send the updated state to the gateway Assistant communication with the gateway will be based on a wireless mesh network This approach speeds up the deployment of new nodes and also assures the modular scalability of the network This also avoids the need to install dedicated communication wiring between the assistants and as a conse quence lowers the installation cost As an example Figure 3 2 shows an approximation of the offices layout in a department and a possible routing path created between the nodes Using a mesh network means that in the case where no direct communication with the gateway is possible messages can still be relayed by another node For example in Figure 3 2 it is possible to note that node A7 is not in range of the gateway G1 1 but it can still forward messages through any other node in its communication radius thus reaching its destination Figure 3 2 An example of RF communication paths within a department 3 2 2 The Gateway The gateway module is responsible for collecting relevant information in strategical zones that can be mainly used to trigger energy efficiency inducing actions For exam
67. layer from the IEEE 802 15 4 standard and the network and application defined by the Zigbee specification 33 35 It provides self organized multi hop and reliable mesh networking which is created on demand and maintained using the Ad Hoc On Demand Distance Vector AODV routing protocol Zigbee defines three device roles the coordinator the router and the Zigbee end device It also defines two different type of devices a Full Function Device FFD and an Reduced Function Device RFD 36 The FFDs can have any of the defined roles but RFDs can only be end devices that communicate only with FFDs A FFDs is used for very simple applications such as light switch or a passive IR sensor thus they can be built using minimal resources and at a very low cost There are two Zigbee application profiles that can be used to develop ZigBee application objects the program itself 33 The first one is the Zigbee Home Automation Public Application Profile for residential or light commercial complexes usually used for light HVAC and security The second one is the Zigbee Smart Energy Profile that is used for load management and response to energy demand 2 2 5 Summary In conclusion to the examined open standards for wireless communication solutions we observed that multi hop is one of the key functions that can be used to overcome some limitations of wireless com munication such as range fault tolerance and network extensibility We have seen that protoco
68. lligan G The 6LoWPAN architecture Proceedings of the 4th workshop on Embedded net worked sensors EmNets 07 2007 78 35 Wendy Guo W Healy W M Zhou M ZigBee wireless mesh networks for building automation and control 2010 International Conference on Networking Sensing and Control ICNSC April 2010 731 736 36 Lee J S Chuang C C Shen C C Applications of Short Range Wireless Technologies to Indus trial Automation A ZigBee Approach 2009 Fifth Advanced International Conference on Telecom munications 2009 15 20 37 Melfi R Rosenblum B Nordman B Christensen K Measuring building occupancy using existing network infrastructure 2011 International Green Computing Conference and Workshops July 2011 1 8 38 Ni L M Liu Y Lau Y C Patil A P LANDMARC Indoor Location Sensing Using Active RFID Wireless Networks 10 6 November 2004 701 710 39 Liu D Guan X Du Y Zhao Q Measuring indoor occupancy in intelligent buildings using the fusion of vision sensors Measurement Science and Technology 24 7 July 2013 074023 40 Benezeth Y Laurent H Emile B Rosenberger C Towards a sensor for detecting human presence and characterizing activity Energy and Buildings 43 2 3 February 2011 305 314 71 41 Violettas G E Theodorou T L Georgiadis C K NetArgus An SNMP Monitor amp Wi Fi Position ing 3 tier Application Suite 2009 Fifth International Conference on
69. ls based on the IEEE 802 15 4 such as Zigbee are the most energy efficient They were especially designed 16 for BACS applications and can function years on a single battery On the other hand their data rate is very restrict and cannot be used for more bandwidth demanding applications The Wi Fi standard offers data rates up to 1 3 Gbp s with the new 802 11ac release but has the disadvantage of high energy consumption It has support for mesh networks using the IEEE 802 11s standard or the Batman adv routing protocols making Wi Fi usable for BA when the devices are not battery dependent As shown by the 6LOWPAN developing standard a big part of tools and services needed for BA can be adopted from the IP protocol which demonstrates the potential of connecting these devices directly to the Internet 2 3 Occupancy Detection Occupancy detection techniques are used nowadays to reduce energy consumption in buildings by supplying lighting HVAC and other building systems with occupancy information Based on it these systems could adjust their configuration and achieve potential energy savings of up to 50 for lighting and 20 for HVAC systems 37 In the next sections we will describe the main technologies used for occupancy detection and user identification 2 3 1 RFID Radio Frequency Identification RFID technology is now widely used in buildings to detect and track occupants or products 38 Itis a wireless communication technology fo
70. mand is needed in order to adjust them Each node represented as Gx will be responsible for collecting the statistics of the departments and passing them up the management chain Apart from that they will also perform actions within the department such as controlling the department s corridor lighting For example the corridor lighting will be managed interacting with the existing LonWorks installation of the campus using the presence of people in the department as an indicator Finally the nodes Ax will gather information about their individual office and perform actions pre defined in the occupants profile such as ambient preferences lights configurations and power socket configuration 3 6 Summary In this chapter the solution to the hardware and software architectures of the system were presented and detailed PerOMAS was designed to cope with a set of requirements that were defined in Section 3 1 These set of requirements conditioned the design choices of the hardware architecture creating a distributed scalable system composed of three kinds of nodes Assistants Gateways and the Core A layered software architecture was also defined It will allow the creation a software application with modular support of hardware and intelligent automation algorithms This chapter ends with a definition of a possible structure for a large deployment at IST s Taguspark campus In Chapter 4 the implementation of the hardware and software architect
71. mind this node will be responsible for services that are common to the whole building It is also possible to use this architecture in small buildings such as residential houses that have a limited number of systems services In this case the intermediate gateway nodes could be unnecessary and the system could operate on a single level e the core being directly connected to the assistants without the need for relaying gateways Moreover in this case all the architecture could run on top of the same hardware performing all the functions 3 3 Hardware Architecture The hardware for the construction of the nodes must follow a set of guidelines in order to assure exten sibility easy installation and enforce the open standards of the project This will help to keep the devices updated and allows for a modular architecture since the peripherals needed for each type of node may be different For example each Assistant will feature sensors for gathering ambient and energy con sumption data which might not be necessary by the Gateway nodes Instead a Gateway may need more actuators or other type of peripheral Figure 3 3 represents the modularity of a Node and the main communication protocols that could be used between the main board and its peripherals 3 3 1 Communication Protocols Normally off the shelf electronic parts such as sensors and actuators are controlled using popular communication protocols such as serial Inter Integrated Circu
72. n another A BT device may participate in several piconets at the same time thus allowing for information to flow beyond the coverage area of a single piconet Shttp www irda org BT was primarily designed as low power wire replacement Its effective range depends on the Class of the device Table 2 1 shows the three possible Classes of devices found in the market their maximum Equivalent Isotropically Radiated Power EIRP and respective range Usually Class 2 devices are used with a range of around 10 meters However some Class 1 devices allow open field ranges of up to 1 km without exceeding legal emission limits Bluetooth Low Energy BLE is a subset of the BT Core Specification v4 0 also called BT Smart adopted in June 2010 21 As an alternative to BT standard BT v1 0 to v3 0 it is aimed at very low power applications running off coin cell It features a lightweight Link Layer providing ultra low power consumption when in idle mode operation and reliable point to multipoint data transfer with advanced power save and secure encrypted connections at the lowest possible cost per device 2 2 3 Wireless fidelity Wi Fi Wi Fi is a brand name for the IEEE 802 11 standard 24 25 22 which is a set of MAC and PHY layer specifications for Wireless Local Area Networks WLANS lt operates in the 2 4 and 5 Ghz frequency bands and uses CSMA CA to control the medium access and offers data rates of up to 1 3 Gbp s with the new IEEE 8
73. n be integrated into a cheap small device that can be installed in every room and personalized for the present occupant or group of people even in the presence of conflicting personal preferences In large buildings these devices can be interconnected to form a network They can work as a distributed platform that manages every room independently to increase the comfort of every user and work cooperatively to increase the building s energy efficiency levels e g by turning off a boiler that serves a floor when none of the offices there is occupied The system will be composed of devices placed at strategic locations and in every office The strate gic locations will correspond to specific location of systems services and their bifurcation in the building in order to control a subset of rooms or building zones Devices will be built from low cost off the shelf hardware They will run on a free and easy to develop software platform with support to high level programming languages The devices will function as an interface between the system and services of every room and the user They will feature sensors for occupancy awareness and ambient sensing used to automatically adjust the room environment to each user based on their feedback ambient and weather conditions and historical data The device will also keep track of the users preferences enable him to specify automation rules and atthe same time enforce general energy efficient rules The below
74. n forced to either return to the same vendor who installed the existing system replace the entire system or install a separate independent system because the communication protocols with the other products are incompatible And in some cases new products can even be incompatible with older products from the same vendor Proprietary approaches to providing these communications have created big challenges for systems integrators and restricted the development of intelligent building technology Even though digital automa tion and control technology has been widely available for a long time intelligent buildings with integrated building services are still more of a promise than a reality 2 1 1 BACnet The Building Automation and Control Networking Protocol BACnet 4 5 6 7 8 was especially devel oped to address the needs of all kinds of BAC systems Key features needed for BA applications were built into BACnet from the beginning In 2003 BACnet has adopted as a national standard by the 28 member countries of EU While BACnet messages can theoretically be transported over any network just a few relevant net works types were standardized They are Ethernet ARCNET Master Slave Token Passing MS TP LonTalk and Point to Point PTP Each of them is a local area network standard except MS TP and PTP MS TP is used for connectivity over Twisted Pair TP using EIA 458 6 signaling while the PTP protocol accesses the communication medium th
75. n of the time it takes to detect a user 5 3 3 Temperature Humidity and Luminosity Results In order to test the functionality of the temperature humidity and luminosity sensors in the Assistants these were used to collect ambient data A day was selected were the presence of the occupants in the office would affect the readings Figures 5 4 5 5 5 6 show the readings of the sensors during October 60 9t 2014 In the figures the line painted in green represents the presence of occupants inside the building Figures 5 4 shows the temperature of the office We need to take into account that during the night the HVAC system is not functional and as a result from 1 AM to around 3 AM the office is warm even though occupants are present Later at around 10 AM the HVAC system is turned on and the temperature is reduced The values then vary with the presence of the users in the office until around 8 PM when the HVAC is turned off again As expected the presence of the occupants highly impacts the ambient characteristics of the office as the system detects their presence and operates the HVAC The oscillation of the temperature when the occupants are present is due to the mechanism imple mented to manage the HVAC Instead of constantly turning on and off the HVAC system the tempera ture in the office must overcome a certain threshold in order to trigger the heating or cooling of the office which causes the oscillating effect The humidity graph
76. n the IEEE 802 15 4 MAC and PHY layer 6LOWPAN or IPv6 over Low power Wireless Personal Area Networks is a developing standard from the Internet Engineering Task Force IETF 6LoWPAN Working Group and defines how to use IPv6 over low power low data rate radio networks as specified by IEEE 802 15 4 standard 32 33 The concept originated from the question Why invent a new protocol when we already have IP 34 and that low power devices with limited resources should be able to participate in the Internet of Things Because the underling protocols are IP based it can make use of all the exiting standards and tools to speed up the development such as Simple Network Management Protocol SNMP for node management Service Location Protocol SLP for service discovery and so on There are also many standardized higher level services such as Load Balancing Firewalling and Mobility that could also be easily integrated Configuration servers also could be eliminated using the ZeroConf and Neighbor Discovery capabilities of IPv6 6LOWPAN also has an alternative when faced with routing Rather than routing the messages using the IEEE 802 15 4 standard layer 2 mesh or mesh under under the IP layer it is possible to build the mesh network on top of IP using standard protocols layer 3 routing or route over ZigBee isa wireless networking technology developed by the Zigbee Alliance The Zigbee protocol is composed of four main layers the PHY and MAC
77. nd management of buildings and homes 12 7 13 In 2002 EIB was merged with Batibus and European Home System EHS creating the new KNX standard with the objective of creating a single European standard for BA The most used KNX medium is the TP cabling variant known as TP1 It carries the signal at a rate of 9600 b s as well as 29 V DC link power The medium access on TP1 is controlled using CSMA with Collision Avoidance CSMA CA and provides up to four priority levels TP1 allows a free topology wiring composed of physical segments of up to 1000 m Using bridges a maximum of four segments can be concatenated in order to form a line which can hold up to 254 devices Lines then are connected via routers named line couplers to form a zone Zones can be coupled by a backbone line or IP tunnels A fully populated network can support roughly 57600 devices The KNX RF medium uses the frequency band reserved for short range devices telecommand telemetry alarms which is in the 868 MHz range The communication is done in a peer to peer manner In addition to devices which support bidirectional communication transmit only devices can also be used such as simple sensors and switches in order to extend battery life and reduce their costs EIBnet IP 14 currently defines two service protocols Tunneling and Routing ElBnet IP Tunneling provides easy remote maintenance access to the EIB KNX network but is limited to PTP communication http www
78. nput methods were tested 41 4 8 Developed connection and power board o e ee 4 42 4 9 Electrical wiring of the sensors actuators and peripherals 42 4 10 Assistantnode ss 23 dna ada Ad eg 43 4 11 The topology of the network aoaaa aaa 45 4 12 Message publishing with different priorities sns 47 4 13 Menu sequence ofthe LCD Ul lll 50 4 14 Registration Menu es 52 4 15 Automation Menu when logged off o e mm 52 4 16 Automation Menu s 3 sas pes Od od a reine PO EL Fe dI de dew RR ER Us 53 4 17 HVAC Controls 2 les s sh ns 53 4 18 Graph Men ong he tea een eed ad da DP Ss 54 4 19 Configuration Menu aaa aaa ee 55 xi 5 1 5 2 5 3 5 4 5 5 5 6 5 7 Test Location 2 0 RR A E a A ee e we ed qe ES 58 Energy consumption spikes created by a 2000W and a 1500W rated heating devices 60 Cumulative distribution function of the time it takes to detectauser 60 Temperature Readings ee 61 Humidity Readings rns 62 Luminosity Readings ees 62 Adjustable temperature to the present occupant nn nn 63 xii List of Tables 2 1 Possible types of Bluetooth BT devices oo nn nn 14 2 2 Most important characteristics of the occupancy detection technologies 20 4 1 The main differences between the most popular SBCs and single board mic
79. ocal Area Network Wireless Mesh Network Wi Fi Protected Access Il Wireless Personal Area Network Wi Fi Protected Access Web Server Gateway Interface Web Services xix xx Chapter 1 Introduction There is a wide range of factors that motivate the rapid creation of more sustainable energy consumption patterns These include the current financial and economic crisis environmental pressures including the global warming concerns and the safety of the energy supply In 2009 Guerra Santin 1 reported that 41 of the total final energy consumption in the European Union EU comes from buildings To explore potential cost effective energy savings the European Commission EC adopted an Action Plan for Energy Efficiency aiming at 20 reduction in energy consumption by 2020 2 As a result a number of standards have been created One way to contribute to this objective is the use of BACS in new buildings to enhance their efficiency Unfortunately not all buildings are equipped with such system Furthermore some BACS offer limited functionality and only to the building managers Due to various factors such as bad user habits lack of knowledge and miss configurations regarding Heating Ventilation and Air Conditioning HVAC and other systems 3 the potential energy gains are not achieved In the majority of cases the occupants are not capable of calibrating the system to provide the best user comfort in the most energy efficient manner poss
80. on a separate execution thread because it has to deal with touchscreen input events in a responsive manner The pybutton library was also used which helped to create and quickly identify the pushed buttons As shown in Figure 4 13 the Ul is composed by a succession of menus that offer manual control of the lighting and HVAC systems and also displays useful information to the occupants Figures 4 13 b and 4 13 c offer an alternative way to control the HVAC system The first menu de fines a score system for adjusting the personal target temperature and the second helps to identify the user In order to rapidly identify the user in Figure 4 13 c the system only shows the occupants present in the office at that moment The scoring system is used in order to conceal the present temperature and during the system use derive their own personal ambient comfort without knowing the actual tem perature The scoring system is used because as mentioned in Section 3 1 2 the users don t know what they want This system lets them choose a higher or lower value in contrast to the actual temperature in the office Since the recommended 30 frames per second re draw of the screen consumes a lot of processing power another alternative had to be found The UI was designed in such a way that the screen is only updated when a change occurs in any element shown on the screen or a change of menu has occurred Figure 4 13 f shows the Uniform Resource Locator URL used to a
81. pdate AC Mode o ES Light Bulb x1 Light Bulb x2 amp amp Cool V Heat OFF 1 2 ka Figure 4 17 HVAC Controls 53 Dashboard fal Graph Hi Settings a Gateway O Admin Y Register E Artur Graphs Temperatures and Humidity 25 D a 245 o o m 2 24 8 3 9 235 a E lt o 23 3S S a 16 00 18 00 20 00 22 00 130ct 02 00 04 00 06 00 08 00 10 00 12 00 14 00 Luminosity 400 350 300 250 200 150 Luminosity Lux 100 0 16 00 18 00 20 00 22 00 130ct 02 00 04 00 06 00 08 00 10 00 12 00 14 00 Power 240 220 200 180 160 Power Watt 140 120 16 00 18 00 20 00 22 00 130ct 02 00 04 00 06 00 08 00 10 00 12 00 14 00 Figure 4 18 Graph Menu 54 G Dashboard MGrapn i Settings A Gateway Admin Y Register E Artur Configuration Menu Your Configuration Your Phone Address is ly 40 B0 FA 3D 5F 08 ly Action Name MAC RSSI Signal Last Seen O Set Phone FireFly 74EE 00 06 66 03 74 EE 82 19 2014 10 13 15 56 26 096037 55690 40 BO FA 3D 5F 08 77 26 2014 10 13 15 56 26 096037 Add Rule Rule Name If Event and then Action Choose Event Add Event Event Alias Estou_no_Gabinete Entre as 16 e 8 Entre as 9 e 8 If In_the_Office Condition True Argument aux
82. ple adjusting the duty cycle of any system service such as an energy demanding equipment The triggered actions could be as simple as turning on a Light Emitting Diode LED or as complex as calling the nearest fire department with accurate information of the building and office on fire The gateway will also be responsible for storing a permanent record of the collected data Analysis of this information could reveal usage patterns and lead to more energy efficient configurations of the system This is very important for services that have big inertia such as the centralized cooling system 26 Some cooling systems use a coolant that is refrigerated during the night Thus instant values of the de mand from such a system cannot be used for adjusting the system in real time and need to be predicted for example by using usage patterns Depending on the building complexity different number of hierarchical levels could be projected following a strategical distribution such as zones building levels or other energy demanding resources Every gateway will also aggregate the data and only pass summary information to upper level gateways lowering data traffic This filtering is very useful in high density buildings as it decreases the load on upper gateways 3 2 3 The Core The Core component will have all the functionalities of the gateway with a single difference it does not need to relay data to gateways in upper hierarchy layers With this in
83. posed system consists of three main components the assistant the gateway and the core The assistant is responsible for the room automation systems and to collect user data via sensors and user inputs The gateway is responsible for collecting data from the assistants and to take actions based on the collected data or to relay it to gateways higher up in the hierarchy The core has the same functions as the gateway but does not have to relay data to any other gateway because it is at the top of the hierarchy it will perform tasks relevant to the entire building s As represented in Figure 3 1 every assistant has two modes either it connects to a single gateway or it works without the presence of any gateway The same way a gateway can connect to one or more assistants and can also connect to a higher level gateway The model enables an adaptable number of hierarchical levels in a tree like format In the next sections we will detail the three main components of the system and briefly explain the proposed instantiation for the IST Taguspark campus 3 2 1 The Assistant The assistant which will be present in every office is the most important component of the system It will be responsible for collecting data from the attached sensors and for controlling the HVAC and electrical systems of the office It will feature an user interface for easy configuration of the assistant important data display and user feedback input Relevant data will be re
84. r data exchange between a reader and a tag An RFID system is composed of two basic components RFID readers and RFID tags 39 The RFID reader can read the data emitted from the RFID tags There are two types of RFID tags passive tags and active tags Passive RFID tags operate without a battery and are very cheap to make but have very limited communication range They reflect the RF signal receive from the reader and add information by modulating the reflected signal They basically allow an ID to be read On the other hand active tags contain a battery to power an incorporated transceiver and because of that can achieve much higher ranges However besides the limited battery life that can last for several years the active tags are very expensive The main use of this technology is the identification and tracking of objects such as commercial products in large stores but the same principle can be used for users The use of passive RFID tags can be a very cheap way of user identification that can be installed at the main entrances A disadvantage of using RFID technology is the requirement of people having to carry RFID tags to be located and the privacy issues that need to be taken into consideration due to the tag being readable by anyone with a reader On the other hand schools and universities and other entities already integrate RFID tags inside their Identification ID cards which is also the case of IST Taguspark 17 2 3 2 PIR C
85. r for the configuration of a new user For this purpose the device will need to have an input and feedback interface Section 2 4 shows the positive effect of feedback from an ECI on the user energy consumption behavior The interface of the device will also function as an ECI in order to observe similar results Main Board Peripherals Temperature Sensor Humidity Sensor STORAGE Luminosity Sensor ME U Movement Sensor m Token Reader l l l l l l l l l l l l l l l O and Actuators l SA Button 1 lt gt l l Figure 3 3 The main communication protocols used between the main board and the peripherals LCD Ys GPIO Expander b D 28 3 4 Software Architecture In order to support the modularity of the hardware the configuration of the software and the application design must also be modular With this in mind the software will follow a layered architecture which will accommodate the use of multi vendor peripherals Figure 3 4 presents the main components of the software architecture and categorizes them in a set of sub layers The presented architecture is designed to run on all types of nodes would it be an Assistant a Gateway orthe Core The main difference between an Assistant and a Gateway would be the connected sensors and actuators A node could even function as both as an Assistant and Gateway at the same time by
86. racteristics such as age distribution level of education or the household size However the only significant variation they found based on user characteristics was that 4 more energy was used by families that were least motivated to save energy A monetary reward system were studied that may serve as a motivator to conserve energy 50 The RFID Passive PIR Vision based Wi Fi Bluetooth Occupant Identification Yes No No Yes Yes Occupant Localization Yes No Yes Yes Yes System Scalability Medium Low Low High High Overall Cost Very Low Medium High Low Low Detection Range Medium Small Big Big Small Table 2 2 Most important characteristics of the occupancy detection technologies 20 results were very encouraging All participating households reduced electricity consumption and in the best case resulted in 12 of reduction in electricity use This indicates that money could be seen as a strong motivator for reducing energy use 3 However the savings decreased as the experiment period progressed suggesting a short term effect of rewards The low effectiveness of measures in reducing energy consumption could be explained by the presence of strong habits 3 Another experiment based on feedback was used 50 which is often applied to promote energy con servation Feedback consists of giving occupants information about the building energy consumption or energy savings It can influence the occupan
87. re 3 5 Proposed architecture for IST Taguspark The HVAC system at IST Taguspark is composed of eighteen heating units distributed between the departments and a central cooling unit which serves the entire building Thus the energy demand for cooling could be calculated and controlled by taking into account all the data of the building further increasing energy efficiency The same process could be applied to the heating units by mapping the 32 departments to a certain heating unit The control of these devices is very important because they contribute significantly to the energy use of a building Observing the architecture presented in Figure 3 5 it is possible to observe that there is a Core node denominated C a series of top level Gateways represented as G 1 Gr2 G1L3 a series of lower level Gateways represented as Gx and a series of Assistants Ax connected to these gateways The Core node collects information relevant to the entire campus such as building occupancy en ergy consumption heating and or cooling demands It will also store a permanent record of these measurements for further analysis of the values that could demonstrate usage patterns This is useful for systems that have big inertia which is the case of the cooling system On the other hand the inertia of the heating system is much lower and can be adjusted within one hour As such a prediction model is not as necessary only the department s occupancy and heating de
88. re tested first a RGB 16x2 Character LCD with five push down buttons connected via the I2C bus shown in Figure 4 7 a and secondly a 2 8 inch color Thin film Transistor TFT LCD with resistive touch screen surface connected through the SPI bus Table 4 3 presents the main differences between the two peripherals In spite of the PITFT having a more complex configuration being more expensive than the 16x2 LCD and requiring more work to design the UI it will simplify the user interaction with the system by means of using a more user friendly graphical UI design thus lowering the interaction time 3http www gimbal com 40 a RGB 16x2 LCD with Keypad b PiTFT 2 8 TFT with Touchscreen Figure 4 7 The two types of displays with different input methods were tested Input Connected Model Vendor Type Resolution Method via Cost 16x2 RGB 16x2 Positive LCD Adafruit BGB Characters Push Buttons ES ao PiTFT TETLCD EMEA Touch Screen SPI 34 95 Table 4 3 Main differences between the PITFT and the 16x2 RGB LCD 4 1 7 Major Problems and their Solution A major problem with hardware is that hardware fails and this thesis was no exception The biggest problems are the ones that take time to occur and because of that hard to replicate and fix Sometimes lower cost hardware cause more problems than expected one of such cases was the popular tempera ture and humidity sensor used in
89. rement of greater loads such as buildings zones models for up to 500 amps are available It will be mainly used to build an ECI as described in Section 2 4 to provide energy consumption feedback to the users Since the Raspberry Pi doesn t have an ADC a separate breakout board the ADS1115 shown in Figure 4 4 will be used ADS1115 is a high precision quad channel 16 bit ADC with an integrated Programmable Gain Ampli fier PGA produced by Adafruit 2 The ASD1115 can be configured as four single ended input channels or two differential channels It has a very low current consumption of only 1504A provides up to 860 samples seconds and uses the I2C protocol http www adafruit com 38 16Bit 120 ADC PGA amp DS1115 _ Figure 4 4 ADS1115 A 16 bit ADC with PGA 4 1 4 Actuators Relays are used to control the main energy demanding devices such as lights Alternating Current AC power sockets and the HVAC system The HVAC system previously controlled by a thermostat besides the Heating Cooling functionality has the particularity of having three levels of ventilation Thus it will need to be controlled with at least four Single Pole Double Throw SPDT relays Two additional relays will be used to control the two light zones in every office which adds up to a set of six SPDT relays that are controlled via the GPIO interface Figure 4 5 shows the two relays modules that were used In order not to damage the GPIO circuitry
90. rks LonWorks EIA 709 technology Kluwer Academic Publishers Norwell MA USA 2001 10 Buchholz P Plonnigs J Analytical analysis of access schemes of the CSMA type IEEE Inter national Workshop on Factory Communication Systems 2004 Proceedings 127 136 11 Miskowicz M Access delay in LonTalk MAC protocol Computer Standards amp Interfaces 31 3 March 2009 548 556 12 Kastner W Neugschwandtner G Eib European installation bus The Industrial Communication Technology Handbook 1 2005 34 1 69 13 Lee W S Hong S H Knx x2014 zigbee gateway for home automation In Automation Science and Engineering 2008 CASE 2008 IEEE International Conference on Aug 2008 750 755 14 Prestandard E Data Communication for HVAC Applications Automation Net Part 4 EIB 1997 15 Lee W S Hong S H Implementation of a knx zigbee gateway for home automation In Con sumer Electronics 2009 ISCE 09 IEEE 13th International Symposium on May 2009 545 549 16 Adams N Gold R Schilit B N Tso M Want R An infrared network for mobile computers In Proceedings USENIX Symposium on Mobile Location independent Computing 1993 41 52 17 Patel J Govindarajan M Shevgaonkar R Analysis of diffuse indoor infrared data links Optical and Quantum Electronics 32 12 2000 1319 1323 18 Gregory J Infrared links between offices Data Processing 27 2 March 1985 26 27 19 Yiannopoulos K Bou
91. ro controllers 36 4 2 Details of the sensors used nn 37 4 3 Main differences between the PITFT and the 16x2 RGB LCD 41 4 4 Type and pooling interval of the virtual devices aooaa aaa 46 5 1 Reading Error caused by the Current Sensor a 59 xiii xiv AC ACR ADC AES Al ANSI AODV AP API ASHRAE BA BAC BACnet BACS BAS B A T M A N BCUs BIBB BLE BMS BPSK BSS BT BVLL CEN CH Alternating Current Algorithmic Change Reporting Analog to Digital Converter Advanced Encryption Standard Artificial Intelligence American National Standards Institute Ad Hoc On Demand Distance Vector Access Point Application Programming Interface American Society of Heating Refrigerating and Air Conditioning Engineers Building Automation Building Automation and Control Building Automation and Control Networking Protocol Building Automation and Control Systems Building Automation System Better Approach to Mobile Ad Hoc Networking Bus Coupling Units BACnet Interoperability Building Block Bluetooth Low Energy Building Management System Binary Phase Shift Keying Basic Service Set Bluetooth BACnet Virtual Link Layer European Committee for Standardization Central Heating XV COV CSMA CA CSMA CSMA CD CSRF DHCP DS DSSS DTO EC ECI EDCA EHS EIA EIBA EIB EIRP ESS ETS EU
92. rocessing on the receiving end without having to deal with message deduplication In case of network failure when the messages cannot be sent the messages are locally stored in three queues one per priority level then sent in the same order using strict priority when connectivity is restored It is possible to configure the Mosquitto broker to encrypt all the traffic using Transport Layer Security TLS but this feature would require much processing power from the Raspberry Pi since it doesn t support Advanced Encryption Standard AES hardware encoding and decoding Assuming the wired network is secure and the wireless network interface already provides enough security this option wasn t further investigated Publishers Subscriber Assistant Gateway Gateway Core Figure 4 12 Message publishing with different priorities The User Manager is the module responsible for creating and managing users It also ensures the security of the users their uniqueness in the database loads the users from the database at start up and stores them whenever a modification is done to the profile The process of creation of a new user requires the specification of a password In order to secure the users passwords they are first salted with a unique salt for every user then hashed using the Password Based Key Derivation Function 2 PBKDF2 hashing function This is the way that National Institute of Standards and Technology NIST recommends storing
93. rough an EIA 232 6 interface A typical application would be to connect to a modem for dial up access to a remote building automation system The LonTalk protocol is limited to transporting BACnet messages over a LonTalk network The Internet Protocol IP was included into BACnet in early 1999 creating BACnet IP Due to this IP networks are natively supported which allows BACnet devices to communicate directly using IP instead of using tunneling routers A BACnet network topology is composed of segments which are physical runs of cable that can be connected using repeaters and bridges BACnet networks which also can be of different media types are connected by routers to form a BACnet internetwork A BACnet network address is represented by a 2 byte network number and a local address of up to 255 bytes The local address depends on the link layer medium which can be an IP address for BACnet IP or a Media Access Control MAC address in case of a Local Area Network LAN The BACnet routers which connect the individual networks route the packets based on the network numbers BACnet uses objects to represent the functionalities and capabilities of a node All BACnet objects have a collection of properties For example an analog input object that reports room temperature will have a current value property which is associated with last read value from the physical input Any device on the BACnet network can have many objects of any type but m
94. rtual device knows what communication library it should use in order to communicate with the hardware The internal state is updated using a polling mechanism to read the new values This assures that the upper layers will instantly access updated values without having to wait for the communication to occur at a cost of slightly outdated values The polling interval will mostly depend on the time it takes to read the values and the available bandwidth and resources For example a minimum of one sample per second for the energy consumption measurements and one sample every fives second for the ambient sensors will suffice In case of the sensors with high refresh rate such as the example of the current sensor which makes 120 measurements per second the average of these 120 measurements will be used Writable virtual devices such as actuators will also update the state of the physical devices upon request from the upper layers The change will then be verified using a read command to ensure the change of the state 3 4 3 Automation layer The automation layer is composed from a set of modules each responsible for distinct tasks The Storage module is used as a persistent database to store information such as e System configuration and parameters e Sensor data readings in chronological order e Registered users and their preferences e System wide and User defined rules events and actions e Logs of triggered events user actions debug informa
95. running two instances of the application in different modes The following subsections explain in detail each of the layers presented in Figure 3 4 Interface Abstraction Layer a General User Interface Automation Layer Hardware Abstraction Layer Virtual Virtual Virtual Virtual Virtual Temperature Humidity Virtual Relay Current Detection Button Sensor Sensor Sensor Sensor Communication Abstraction Layer Figure 3 4 Abstraction Layers of the Application User Interfaces 3 4 1 Communication abstraction layer This layer includes a set of libraries that abstracts the communication protocols from the rest of the application They will offer simple primitives similar to Read and Write abstracting the complexity of each protocol such as sessions communication errors and retries These could be hardware specific protocols such as I2C and SPI or tunnels to remote systems based on IP An example could be an HVAC system managed by a remote BACnet or LonWorks system that receives Application Programming 29 Interface API specific commands over IP 3 4 2 Hardware abstraction layer The Hardware abstraction layer will abstract every sensor actuator and external manageable service as a virtual device Every virtual device is defined as a stateful object that reflects the present state of a physical device and can be a ReadOnly device or a Readable and Writable device The vi
96. s to an office and 51 of those share the office with at least one other person and an average of 3 87 other occupants Also 37 of the users who share a office with other users stated to have conflicted preferences for HVAC settings that cause them discomfort Regarding energy related user habits 72 of all users reported to only shutting down the HVAC system sometimes when leaving the office Likewise 43 said the same about the lighting in the office When asked about the preferred temperature in spite of big variations the average temperatures were 22 4 C during winter and 19 9 C during the summer These values could be used as a starting point for the user preferences calibration 24 These values also show that the users don t know what they want Usually during summer the occupants use less clothes and as a result they withstand higher temperatures During winter the occupants tend to use lower temperatures because of the extra clothes they wear 3 2 Architecture Overview To ensure the scalability of the system a hierarchical architecture shown in Figure 3 1 was developed that better adapts to the required application It follows a centralized hierarchical architecture because of the way the building services are installed such as the HVAC system or electricity In a building these services always merge at a single point where they can be measured and controlled and as such our model will follow the same principle The pro
97. stics were sum marized in Table 2 2 PIR detections systems didn t have any mechanisms for user identification which is very important when taking into consideration a multi user system with different preferences Vision based detection can be used for user identification but for that we need a database to control the readings too which is again user intrusive and a resource demanding process On the other hand RFID Passive tags showed to be very cost effective and used in many commercial Figure 2 3 Blueprint of the library area at IST Taguspark with the position of some APs and the number of STAs connected to each of them 19 applications especially for product identification in logistics But they have to be carried with the occupant in order to function and there are also privacy issues regarding their use Considering that the building is equipped with a Wi Fi system and that the user always carries a smart phone or a laptop this system could be cheaply modified to support occupancy detection as demonstrated in Figure 2 3 But has the problem of having low accuracy Thus BT technology could be used inside the offices which again paired with a smart phone could provide the needed accuracy The combination of these two technologies could be a solution for accurate user identification and localization in dense office buildings 2 4 Human Behavior The human behavior is composed of habits which are often described as
98. t behavior because they can associate energy savings with their own behavior In this case the building was equipped with a monitor also known as ECI 51 that displayed the electricity use in cents per hour On average the group of occupants which had a monitor installed used 12 less electricity than the control group This kind of monitors are very common nowadays usually installed in intelligent houses For example Cloggy is a Portuguese ECI solutions from ISA Energy Figure 2 4 represents an example of the user interface of this kind of systems A recent field experiment aimed to determine if social influence played a role in the energy con sumption behavior of users based on eco feedback 47 Eco feedback is a technology that provides feedback on individual or group behaviors with the goal of reducing environmental impact 52 In this case the study objective was to maximize the spread of information about conservation measures that users could explore in order to reduce energy consumption across everyone in the system The idea is that social integration could substantially increase the efficacy of eco feedback systems leading to long term sustained reductions in energy consumptions The study concluded that social influence in fact impacted the energy consumption behavior of users and also indicated that users were influenced towards reducing their consumption rather than increasing it In conclusion to a survey done to UK habitants 3 it
99. t decade wireless sensors and actuators networks have gained momentum receiving a lot of attention from the BA industry and standards development organizations The use of wireless commu 12 nications allows flexible addition and removal of devices to and from the network But more importantly it reduces installation costs since wired solutions require cable trays or conduits However this medium has its own challenges and limitations due to the nature of radio propagation Some of these technolo gies have had commercial success despite of these limitations 2 2 1 Infrared IR IR wireless is used for short and medium range communication and control where devices communicate through IR radiation 16 Some systems only work in Line of Sight LoS mode that require unobstructed straight path between the transmitter and the receiver Others support diffuse or scatter mode 17 where the signal can bounce off the surfaces and still be received even without LoS But unlike RF links IR cannot pass through walls This can be seen as a problem but in other scenarios it may be seen as a security feature Some IR systems offer a level of security comparable to that of hard wired systems For example it is harder to physically eavesdrop on a LoS IR laser communication link than a Wireless fidelity Wi Fi connection IR technology is used in a variety of peripherals such as remote control units intrusion detectors cordless microphones and handsets
100. t the moment when the 2000W rated heater was turned on The device then maintained a constant power draw until it was switched off at 6 53 AM which caused a drop in power consumption reading from 2157 0W to 190 2W representing a drop of 1966 8W Also shown in Figure 5 2 is the second test that took place from 10 15 AM until 10 20 AM using the 1500W rated heat gun The heat gun caused an energy consumption spike from 183 9W to 1631 1W when turned on and then a decrease from 1633 0W to 183 7W when turned off resulting in a difference of 1447 2W and 1449 3W respectively The real energy consumption of the devices were measured beforehand using a multimeter and are presented on the third column of Table 5 1 Columns four and five show the average measured values by the Assistant and the induced error compared to the real energy consumption values The introduced error in the readings is acceptable taking into account the background noise generated by other equipment and quantization error intro duced by the 16 bit resolution of the ADC This also shows that the consumption readings are very accurate and are suitable for the intended application of an ECI discussed in Section 3 3 3 Electrical Real Observed Average Equipment Power Rating Energy Consumption Energy Consumption Ertor Heater 2000W 1947 83W 1976 95W 1 495 Heat Gun 1500W 1433 13W 1448 25W 1 055 Table 5 1 Reading Error caused by the Current Sensor
101. ted power Typical range mW dBm m Class 1 100 20 100 Class2 2 5 4 10 Class 3 1 0 1 Table 2 1 Possible types of BT devices 14 AP Access Point BSS Basic Service Set E np ESS Extended Service Set Bc T IBSS Independent BSS Figure 2 2 IBSS and ESS configurations of 802 11 networks 22 IEEE 802 11s is an IEEE 802 11 amendment that describe the necessary functions to form a Wireless Mesh Network WMN 25 28 The basic element in 802 11s is the Mesh Point MP which is different from any other 802 11 entity MPs can exchange messages with other MPs that can be multiple wireless hops away This is possible because a MP has relaying capabilities similar to an AP which allows it to forward messages for communications that it is not involved in The IEEE 802 11s also uses strong security mechanisms and power saving techniques that have their own challenges due to the distributed nature of the network Batman adv or Better Approach to Mobile Ad Hoc Networking B A T M A N advanced is an open source multi hop routing protocol based on the ad hoc mode of the IEEE 802 11 standard 29 30 It is classified as simple and robust proactive routing protocol for establishing multi hop routes in ad hoc networks B A T M A N does not maintain the full route to the destination instead each node maintains only the information about the best next link to be used as a gateway which saves resources and proc
102. the OS is not powerful enough it may cause significant delays in the 42 a The front of an installed Assistant node c Relay connected to the Assistant Figure 4 10 Assistant node development phase and limit the potential of the hardware The chosen OS is a flavor of the Debian Linux distribution Raspbian Raspbian is very stable and especially optimized to run on the Raspberry Pi SBC It has repositories with pre compiled software for easy installation on the Raspberry Pi that speeds up the time needed to start developing on the platform Because it is a widely used platform it has great support from the community 4 2 2 Programming Languages The Python programming language was chosen for the development of the main application It is a fast powerful cross platform and widely used programming language supported by a vast majority of https www debian org Shttp www raspbian org Shttps www python org 43 OSs and it is capable of preforming well in resource constrained systems In particular version 2 7 of the Python language was selected because it is the most widely used by the community and has a large quantity of open source libraries It is very popular because it offers multiple programming paradigms and also because the development of new application is very fast the produced code is very easy to read and understand On the other hand some sensors from Adafruit mentioned in Section 4 1 3 alread
103. the first prototype the DHT22 The problem with the DHT22 was that it didn t use the official Dallas one wire protocol and some workaround was needed to make it work on the Raspberry Pi But the code was not stable which caused the sensor to freeze after a random number of hours The sensor caused too much trouble and was replaced by the before mentioned HTU21D that uses the I2C protocol Some problems only occur during the system integration and field testing One thing is to test the components individually which behave normally another is to see them interfere causing energy con sumption spikes which in our case was the fault of the coil based relays and their high energy demand For this purpose and in order to ease the installation of the sensors a power distribution board showed in Figure 4 8 was developed The Raspbery Pihas a 1 1 A polyfuse on the microUSB input port making it responsible for many of the components being under powered The board surpasses this power deliv ery limitation by bypassing this fuse entirely Instead of powering the components through the Raspberry Pi they are directly powered through the power board A 26 pin ribbon cable provides the connection between the power board and the Raspberry Pi it supplies power to the main board and bridges the connectivity pins to the power board where the rest of the components are connected except the USB dongles which are directly connected to the Raspberry Pi The board also
104. tion The Event Manager module is responsible for adjusting the system state depending on the occurring events Every events are composed of set of rules and a set of actions In order to trigger the actions all the rules must be satisfied A rule could be as simple as comparing a sensor value to a constant but may also be sophisticated For example a rule may contain complex algorithms to determine if the actual temperature satisfies all the present users of the office based on historical readings of sensor values and the behavior of the occupants 30 There are system wide events and user defined events The system wide events are configured by the system administrators to enforce energy efficiency and user comfort at the building scale User define events are configured by the occupants for their offices offering them a high level of automation and independence The User Management module is responsible for creating deleting and maintaining user profiles It is also used to manage user security credentials and identification tokens which are used to localize the occupants The module may also enforce access restrictions to certain features that only users with administrator privileges have access to The Publish Subscribe modules are used to communicate between nodes Normally the Assistants only use the publish module to send information to separate communication channels for each sensor value event or other important information On t
105. tion of user automation rules actions and events 31 Every Gateway and the Core node will also present the above information but in relation to the building zone they are responsible for combining the values from the assistants Their automation rules and events will be triggered by the information from their assistants or other gateways and applied to the service s they are bound to The LCD interface mainly serves as an ECl for the occupants Using this UI they also have the ability to manually override the system They would be capable to perform the normal tasks of the devices that the new hardware replaced such as the lighting switches and the thermostat control More complex tasks would also be possible For example when a user is not in possession of the ID token and willing to trigger the automation process The interface will have multi user support used to distinguish between occupants This is useful when giving personal feedback to the system using this UI The CLI interface is used for administrative purposes It will offer low level access to the internals of the main application It will allow executing all the possible commands offered by the other Uls in a command line interface 3 5 Deployment at IST Taguspark In order to ensure the scalability of the system at IST Taguspark the hierarchical model from Sec tion 3 2 was applied to the main building obtaining the system architecture shown in Figure 3 5 Figu
106. to store intermediary readings ever few minutes depending on the type of sensor and their inertia This data is later used for historic analysis of the sensors readings Another use of the Scheduler module is to periodically send sensor data to the Gateway This is done at a much higher rate in order to archive better reaction times of the Gateway to the sent data Tasks could also be added to the pool at any time by users or administrators The Event Manager module is used to adjust the system state based on a set of pre programmed triggers Its functionality is similar to the Schedulers but differs in terms of what causes a specific event to be executed Every event is composed of Rules and Actions In order to trigger the actions all the rules must be satisfied Algorithm 1 presents a simplified version of the main loop of the Event manager execution thread for Event in EventsPool do executeEvent TRUE for Rule in Event do if Rule is Invalid then executeEvent FALSE break end end if executeEvent then for Action in Event do executeAction Action end end end Algorithm 1 The algorithm for the main loop of the Event manager execution thread The event manager executes system wide events and user defined events The system wide events have priority over user defined events and are configured by the system administrators to enforce energy efficiency User defined events are configured by the occupants of ev
107. ts in the distinct parts of the building thus improving energy efficiency For example if system X is responsible for serving a number of rooms and only one room is using that service then system X can be configured to fulfill the actual demand Depending on the system the actual energy savings can vary and can even reach the 100 mark when the system in not being used in any room 1 4 Thesis Contribution The following list presents the main contributions of this thesis e Hardware Architecture Design of a prototype node capable of integrating multiple sensors am bient energy consumption occupancy localization and inputs as well as network interfaces for communication e Software Architecture Design of an application to run on the target hardware that offers the user the control of the local HVAC and lighting services while recording ambient and power usage data e Network Architecture Design of scalable easy to install network architecture with independent nodes and collaborative goals e User Interface Development of two user interfaces for easy control of the system a primary web based interface for user registration remote system control and detailed information display and a secondary interface for the device s Liquid Crystal Display LCD touch screen for easy feedback input and important data display e Automation and Management Algorithm Development of an algorithm capable of dealing with conflictin
108. upants of a certain area Due to the 18 big coverage area of a single cell the accuracy can be fairly low but is enough to determine if a user is in a certain zone of the building 2 3 5 Bluetooth BT is a low cost technology that is currently built in in most of the mobile phones 21 This fact can be exploited to use the technology for localization proposes There are two main used methods for device localization using BT connection based and inquiry based 42 Connection based systems use the RSS of the established connection between the master and the slave This mode has the disadvantage of having to configure the device Authorization between the two devices is needed using a PIN code which makes the devices connectible even when in hidden mode This mode also has limited scalability because of the BT limitation of only seven connections Inquiry based makes use of the device discovery protocol for allowing a device to find a neighbor before establishing a piconet This method also returns the RSS of the inquired device The main disadvantage of this method is that the devices need to be in visible mode in order to be detected A study showed that both of the methods are suitable for tracking room level proximity between BT devices with a range of 5 m 43 which is a smaller coverage area than that of Wi Fi but much more precise 2 3 6 Summary In conclusion to the examined technologies of occupancy detection the main characteri
109. ure is detailed in depth 33 34 Chapter 4 Implementation This chapter addresses the main decisions taken in order to implement the hardware and software architectures presented in Chapter 3 This chapter is divided in three main sections In Section 4 1 the detailed hardware architecture is described Each of its subsection shows the decisions taken in the selection of the components Section 4 2 describes the implementation of the software architecture This section is composed of several subsections that detail the software configuration and explains the developed code Finally Section 3 5 details the deployment of the system in a set of offices at IST Taguspark 4 1 Hardware Architecture 4 1 1 Single Board Computer Following the guidelines of Section 3 3 a small controller board capable of supporting a range of proto cols must be chosen to be used as the base for the development of the nodes Multiple boards were taken into consideration with special attention to the connectivity ports price and computational speed These factors are very important since they will define the modularity and flexibility of the nodes Table 4 1 shows the main differences between the most popular Single Board Computers SBCs and micro controllers existent on the market that are relevant for our purpose The Arduino Uno Single board Micro controller is a very popular device but does not fit our needs since it is very limited in terms of storage
110. urrent buildings usually use Passive Infrared PIR technology for occupancy detection 39 It is com posed of IR sensors and works by detecting the electromagnetic radiation emitted by the person when they pass by But it has some major disadvantages for the purpose of occupancy detection 1 IR sensors are sensitive to sunshine radiation 2 static persons cannot be detected 3 the IR radiation can be easily blocked by ordinary glass or plastic and 4 detection fails when multiple persons pass through the sensor at the same time These factors cause miss readings by the system Also there is no mechanism for user identification On the other hand there is no need for the use of any specific device for people to be detected 2 3 3 Vision based Occupancy detection can also be done using the video surveillance now widely used in buildings By analyzing the captured images it is possible to deduce people s shapes and movement A number of approaches have been developed which are divided into three main categories motion analysis feature based detection and mapping based methods 39 Motion detection and tracking focus on extracting object silhouettes from consecutive frames using motion analysis Feature based detection are more appropriate for accurate human detection in static images such as faces or parts of the body using machine learning algorithms Mapping based methods are used for statistical mapping between the number of person on
111. ust have at least one object the Device object This object is used to control and report various characteristics of the device The object model present in BACnet can be easily extended to include new objects or properties While objects give an abstract representation of a BA device BACnet services provides commands for accessing and manipulating this information to automate tasks BACnet defines 40 services which are grouped into five categories Object Access File Access Alarm and Event Remote Device Man agement and Virtual Terminal Who Is I Am and Who has l Have are remote device management services that are used for dynam Operator Workstation lt gt SS Point to Point Tunnel to remote subsystem Management Network O E N o Automation Netwoi k Automation S Unit Fire Alarm Q Level Controller EN Panel Field Network m TERM OOD Figure 2 1 Example of an BAS system Management Level Supervisory Controller ically discovering devices and specific objects using their object name or identifier Other such services are used in the BACnet network for time synchronization and device reinitialization Several BACnet device profiles have been defined in order to simplify the vendors work Each of the profiles is a collection of BACnet Interoperability Building Blocks BIBBs that are intended to be implemented in the most common BA equipment such as smart actuators smart sensors building
112. y supplied example code written in Python The main application also makes use of other languages such as Hyper Text Markup Language HTML and JavaScript for the creation of World Wide Web WEB pages templates Structured Query Language SQL is used for accessing and storing application variables and configurations in a local MySQL database instance Bash start up scripts are also used for the configuration of the mesh network and auto installation of packages before the execution of the main application 4 2 3 Auxiliary Programs and Libraries In order to ease the development of the application a set of auxiliary programs and libraries were used For distributing the messages between nodes the open source Mosquitto message broker was used lt uses the lightweight Message Queue Telemetry Transport MQTT protocol which is designed for Machine to Machine M2M communications in a publish subscribe model A Mosquitto broker will be installed per building zone in every Gateway and Core nodes Instead of having one single broker running on the Core node this approach will decentralize the system The Assistant s main application will then use a python binder to connect to the zone broker in order to post messages For the development of the LCD UI the pygame Python library was used It is a set of modules that allow easy creation of games and multimedia programs which supports the frame buffer driver used to display pictures on the PiTFT
113. yer offers a particular support for the manipulation of network variables Management and diagnostic services include querying the content ofthese variables node status read ing and writing memory device identification and router configurations Normally the nodes are based on a chip from the Neuron series by Echelon but there are also other embedded controller solutions such as from Loytec These controllers execute the seven Open Systems Interconnection OSI Layers including the application program itself which accesses the sen sors and actuators connected through the Input Output I O interface The controllers are programmed using ANSI C whereas the Neuron chips are programmed using the Neuron C programming language 5 which is based on ANSI C There are entirely non open systems which are build using LonTalk technology Moreover the Lon Mark International founded in 1994 defines guidelines in order to ensure interoperability between de vices from different manufacturers They include LonTalk channel profiles Standard Network Variable Types SNVT and functional profiles Many functional profiles have been published many of them re lated to BA such as Constant Light Controller Scheduler Occupancy Sensor and others that are freely available but are not a part of any formal standard 2 1 3 EIB KNX The European Installation Bus EIB 12 7 is a fieldbus protocol that was designed for decentralized monitoring control a

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