Here - Efficiency Vermont
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1. connected devices based on 32 bit ARM Cortex M microcontrollers Such devices are also known as Internet of Things devices Applications may be only developed for the mbed platform using the mbed online IDE a free online code editor and compiler Code is written and compiled within a web browser and compiled on the cloud using the ARM C C compiler The cellular networking module on the Arch GPRS V2 is the SIM900 Quad band GSM GPRS engine from SIMCon With this data collection functions can be performed easily using the 2G GSM GPRS based cellular network How This Impacts Our Design The mbed enabled Arch GPRS V2 is a great microcontroller for what our design consists of The low power ARM Cortex MO core will have great sleep characteristics lt 2mA Mbed will 31 provided great online development tools along with forums and documentation The SIM900 Module will allow us to send the data to the cloud Also there is a built in microSD card slot on the bottom of the board 6 2 Sensors Problem Our wireless building monitoring system will utilize a variety of sensors to collect data on the building Ideally the system will have sensors that measure the following e Temperature amp Humidity e Light Level All of the sensors need to be compatible with the Arch GPRS V2 Looking at the tech specs provided the Arch GPRS V2 microcontroller has 3 3 5V power All sensors considered must be within this range of operation The Arch G2. however due to time constraints we will only employ long term testing up to a certain point Send Data to Gateway Sending data to the gateway must be reliable To ensure this reliability our group will complete a series of tests where data is sent across sensor nodes to the gateway Having known the data that was transmitted the received data at the gateway should match this transmitted data If not our system has an error and the troubleshooting process must begin until the error is fixed Send Data to Remote Server 18 Sending data to a remote VEIC server must be reliable as well due to VEIC needing this data to perform data analysis to make these buildings more efficient To test this our group will employ the same method as above Knowing the transmitted data we can check whether the same data was received at the remote server If not our system again has an error and we will troubleshoot to fix this Check for Outage and Send Outage Alert Checking for an outage is simple if data cannot be transmitted or data isn t being received then there is an outage Our group will perform tests on both the transmitting side and receiving side On the transmitting side if the device cannot transmit data to the cloud there is an outage and an alert will be sent On the receiving side if no data is received in a given amount of time there is an outage and an alert will be sent In trials if this procedure does not work properly we will trou
3. included with the system The online database allows for configuration and troubleshooting of all parts of the system with the ability to locate the problem area including network connectivity as well as checking values for validity The system will send alerts for initiating troubleshooting when faced with a connection outage The total cost of the system will be approximately 1 000 and last at least 5 installations 1 3 Key Objectives Our team identified five key objectives for this project e lowcost e ease of use e reliable e adaptable e easy to ship These objectives will allow us to meet the requirements from our client and produce a product that will perform the essential functions 2 Design Overview Our design was to make individual nodes each comprised of its own microcontroller cellular data plan and set of sensors Figure 1 below shows two nodes and how the data will be transferred over cellular network Each node will have a temperature humidity and light level sensor to collect environmental data along with an individual sim card and microSD card to transmit and backup data Each node will upload to ThinkSpeak com which is an Internet of Things API with a great easy to use use interface Each node will have to be configured by the auditors at Efficiency Vermont The microSD will carry an executable java file which when selected will run our configuration GUI The user will enter the project s informatio
4. Algorithms and Cost Assumption 8 Sept 2013 44 lt http www greenmountainpower com upload photos 371TRM_User_Manual_No_2013 82 5 protected pdf gt Overview First Fuel N p 2014 Web 21 Sept 2014 lt http www firstfuel com platform overview gt Wikipedia United States Frequency Allocations Chart 2011 The Radio Spectrum 1 Aug 2011 lt http en wikipedia org wiki File United_States_Frequency_Allocations_Chart_2011_ Th e Radio _Spectrum pdf gt Storage and Analytics for the Internet of Things GroveStreams N p n d Web 20 Apr 2015 lt https grovestreams com index html gt SkySpark SkyFoundry N p n d Web 21 Sept 2014 lt http www skyfoundry com skyspark gt Xively by LogMeln Xively N p n d Web 20 Apr 2015 lt https xively com gt Appendices A Users Manual VEIC Step By Step New Node Documentation Steps for setting up ARCH for Windows 8 computer 1 Goto Settings a Change PC Settings b Update 8 recovery c Recovery gt Restart now d Troubleshoot gt Advanced options gt Startup Settings gt Disable driver signature enforcement 2 Download zip file https mbed org media uploads samux serial zip 3 Save file and extract 45 4 Open Device Manager 5 Action gt Add Legacy Hardware gt Next A Device Manager 0 Qua Scan for hardware changes 4 z Add legacy hardware Help 4 Bluetooth RTL8723A 4 0 Hig
5. in their buildings To ensure that our system is reliable we tested the system s ability to respond to errors making sure that it can correctly locate the problem area check values for validity and send alerts to Vermont Energy Investment Corporation and the customer when there is an error In order to be reliable our system must be able to last 5 installations To ensure this we measured the battery life of the system as well as the amount of data it is able to log and buffer We also tested the durability of the system We made sure our system was adaptable by first testing each sensor to ensure that it performed to the necessary standards Then we tested an entire node with different sensor configurations 13 We tested several nodes transmitting data simultaneously to the online database We also tested the system s ability to cover an area of 20 000 sa ft 3 4 Objective Results This section will analyze whether we were able to meet our main five objectives that we set out in the beginning of the project 1 Low Cost In the original problem statement it set the total cost of the system as 1000 We were able to create a system node for a total cost of 252 07 This means we could have 4 nodes in a building which would be adequate to cover the 20 000 sa ft Using a low cost microprocessor and minimal part we were able to satisfy this objective 2 Ease of Use Our system needs to be easy to use and have a good user interf
6. our needs However we were unable to get an account Therefore due to the ease of use we choose ThingSpeak as our online tool We were unable to get a successful test of the grovestream API however if battery lifetime was a concern it would be worth it to pursue this in order to send multiple data points at one time 7 Test Results For testing of our system we are to compare the data collected from our system to the existing sensor that are deployed at Efficiency Vermont The HOBO datalogger is the current sensor station they use to monitor buildings 7 1 Accuracy of sensors Figure 25 On the left we have the HOBO and the right our system 39 Temperature Sensor Testing 40 Temperature F e HOBO Temperature Sensor DHT Temperature Sensor 4 26 2015 13 48 4 26 2015 14 02 4 26 2015 14 16 4 26 2015 14 31 4 26 2015 14 45 Time Figure 26 Test results between HOBO and our system s temperature sensors Figure 26 above is our test results for the temperature sensors The blue is the HOBO s data and the grey is our system s data As you see the HOBO provides more accurate data then our system This we believe is result from our code Also our systems temperature changes more rapidly than the HOBOs this is desired when monitoring buildings We believe this result is because the HOBO s temperature sensor is inside the casing while ours is outside 40 Humidity Sensor Testing Ww Relative Humidity 96
7. y 4 HOBO Humidity Sensor 4 DHT Humidity Sensor 4 26 2015 13 48 4 26 2015 14 02 4 26 2015 14 16 4 26 2015 14 31 4 26 2015 14 45 Time Figure 27 Test results from HOBO s and our system s humidity dat Figure 27 above is our test results for the humidity sensors The orange is the HOBO s data and the yellow is our system s data As you see the HOBO provides more accurate data then our system We still believe that our humidity sensor is sufficient to run energy audits 7 2 Repeated Installations We determined that our system would last 5 installations due to our system setup and choice of components The configuration file allows the same node to be used for as many different buildings and configurations of sensors as possible The rechargeable battery and easy access to the battery charger allows the node to be recharged without opening up the case The rest of our components were chosen to last for multiple installations 41 7 3 Cellular connection To test cellular connection we used the trial and error approach with different buildings made of different materials We know that the Votey Engineering building is one of the worst for cellular connection We found that in some rooms in Votey our system connected while most others our system failed to connect Our system will not be adequate for a building like Votey 7 4 Battery consumption 9 A yr yr O S gt Time Figure 28 Test results f
8. 11 The Arch GPRS V2 development board The Arch GPRS V2 made by Seeed Studio is an mbed enabled development board The Arch GPRS V2 was chosen because it houses a SIM900 cellular networking module along with a built in microSD slot It holds the LPC11U37 microcontroller has a low power ARM Cortex MO core and 128kB flash 12kB SRAM and 4kB EEPROM on chip memory Figure 12 The DHT22 temperature and humidity sensor The DHT22 is a digital temperature and humidity sensor that requires 3 3 6V input voltage 1 1 5mA measuring current and 40 50 uA standby current lt can measure humidity from O to 100 RH relative humidity and temperature from 40 to 80 degrees Celsius It has 2 RH accuracy and 0 5 degrees Celsius accuracy 21 Figure 13 The TEMT6000 ambient light sensor breakout board from SparkFun Electronics The TEMT6000 ambient light sensor is a silicon NPN epitaxial planar phototransistor in a miniature transparent mold for surface mounting onto a printed circuit board The device is sensitive to the visible spectrum The device acts like a transistor where greater incoming light will rise the analog voltage on the signal pin In the code a scale is created to determine if a room is dim or bright and this is displayed to the user Figure 14 The RTC real time clock module from Sparkfun Electronics 22 The DS1307 RTC module keeps track of the year month day and time up to the second The module is necessary to tim
9. 2 Figure 16 System design Figure 17 shows plotted temperature and humidity data on our ThingSpeak account 24 Field 2 Chart xro Test 75 3 50 25 21 00 22 00 23 00 Date ThingSpeak com Field 1 Chart xrom Testl 80 3 60 8 3 E 5 40 20 21 00 22 00 23 00 Date ThingSpeak com Figure 17 Data acquisition humidity and temperature 25 5 3 Casing Design Problem The primary objective of the enclosure is that it will properly secure and protect the node s components from damage The case needs to provide impact durability to extend the system s lifetime Each node in the system consists of an Arch GPRS V2 connected to a DH22 temperature amp humidity sensor a TEMT6000 ambient light sensor a DS1307 real time clock module a LED a switch a polymer lithium ion battery and a polymer lithium ion battery charger All of these parts must be fastened to ensure the components are not hitting each other inside of the enclosure and failing Although a node may not require all of the sensors each node must have the capability to connect to them The sensors must be placed outside of the case to monitor environmental conditions Therefore each of these sensors must be properly secured to the outside of the casing Also each case will need to be closed and opened with easy to allow for access of inner components for repair maintenance and debugging The secondary objective is designing a case that is visual
10. 20 000 sq ft The gateway feeds collected data into a remote server preferably through a cellular connection The sensors will constantly pre process data before sending it to the gateway In case of a network interruption the sensors must buffer for 2 weeks and the gateway must be able to log data for 12 months The sensors must last up to 3 12 months on battery power and log data at 5 minute intervals The system will be easily set up by a customer with rudimentary training or an electrician with provided instructions It will have the ability to collect data from a variety of compatible sensors relative and external temperature humidity and magnetic field sensors as well as generic 0 5V and 4 30mA inputs which will be included with the system The hub will provide data to a web based admin interface which allows for configuration and troubleshooting of all parts of the system with the ability to locate the problem area including network connectivity as well as checking values for validity The remote server will collect data as well as be browsable and able to send alerts for initiating troubleshooting when faced with a connection outage Our system will likely utilize existing technologies such as Pinoccio The total cost of the system will be approximately 1 000 and last at least 5 installations During the second semester we worked extensively on designing our system Throughout the design process we needed to work with ou
11. 4 3 Requirements Gather Environment Information Our client s main objective for our project is to gather environment information to perform an energy audit Data points must be measured every five minutes to get an impression of what is happening inside the building that is being audited This will be easy to check by trial if the data is not being measured every five minutes there is an error and the sensor node will be troubleshooted The Arch GPRS V2 must have 3 months of battery life To test this our group will perform multiple small timeframe tests on operation of the device when the device has various amount of charge left to ensure this battery life will be satisfied The system must be able to cover 20 000 square feet To test this our group will perform various small scale testing and eventually a large scale test to make sure the area covered is sufficient Finally the data must be recorded accurately To ensure this our group will have to test and compare measurements done by hand and those done by the sensor Buffer Data The buffering of data must reliably store the data collected at a minimum of two weeks To test this our group will perform small timeframe testing to measure the reliability and after move up to the full two week timeframe testing Log Data The logging of data must be reliable to store data collected at a minimum of three months To test this our group will employ the same strategy as in the buffer data case
12. GPRS V2 Create ThingSpeak account Configure Arch GPRS v2 System mailed to customer in compact package Provided with step by step instructions for setup Figure 3 Ease of use portion of the objective tree The system needed to be reliable It was important that the system was able to troubleshoot in response to errors locating the problem area and checking values for validity It also needed to send alerts to Vermont Energy Investment Corporation and the customer when there was an error The Arch GPRS V2 must have a 3 month battery life to last throughout the energy efficiency analysis In case of an outage the online database must be able to log data for up to 12 months and the Arch GPRS V2 must be able to buffer data for 2 weeks both at 5 minute intervals Sensor nodes must constantly preprocess data The system must last at least 5 installations before it needs to be replaced Online database Ability to troubleshoot Web admin interface 3 month battery Lasting battery life Reliable Log data Offline capabilities System will last at least 5 Buffer data installations Figure 4 Reliable portion of the objective tree Troubleshooting of all parts of the system Online database must log data for up to 12 months Log data at 5 minute intervals Arch GPRS V2 must buffer data for 2 weeks Buffer data at 5 minute intervals Ability to locate problem area Checks values for validit
13. Keys IRAUN Run the executable file on the microSD card Fill out the following information including the API key from step 6 Remove the microSD card from the computer and insert it in the Arch GPRS V2 Turn on with the power switch and it will begin recording If configured correctly LEDs will flash Building User Step By Step Documentation I e OUN Open package and take out nodes s Attach node s according to directions Flip power switch to On position Log on to ThingSpeak account and make sure data is being transmitted Contact Efficiency Vermont if node does not turn on or no data is transmitted 48 B Total Budget Unit Pricg Subtotal ipping Cog Desoriptior Vendor sses 1755 802 USBMinBCable 6 Sparifun com Subrot 1 410 05 s9995 09 95 SparkFun Celular Shield Sparifun com Shippin 209 09 ss995 17885 SparkFun RedBoard Sparifun com total 1 619 94 sosa 4995 665 SD CardBreakout Board CuteDig Fs29 00 39 00 SM900 GPRSIGSM Shield __ CuteDigi 5 2 w reak Away Headers rdunio Stackable Header Kit umper Wires Premium readboard SparkFun umidity and Temperature emperature Sensor Wate SparkFun all Sensor Sparkfun 32 95 Ah Lipo batteries Sparkfun 21 98 21 98 0 00 printer filament amazon SparkFun USB LiPoly Charger ST Jumper 2 wire Assembly SPDT Mini Power Switch lament 1kg reak Away Headers Straight Ah LiPo Battery mbient Light Sensor ST Jumper 2 Wi
14. Like any radio frequency transmission wireless networking signals are subject to a wide variety of interference as well as complex propagation effects that are beyond the control of the network administrator Security is a weakness of the wireless network How This Impacts Our Design Based on the most important object reliability using a cellular network is the most appropriate choice for our design There is also a big issue of security for the wi fi network 37 6 5 Data Collection and Live Stream Problem It is important for our client to be able to have access to a live stream of the sensor data online to make sure the sensors are transmitting and reporting correct values In order to do this we will need an online tool to collect the data and display the live stream Approach We will use an online service to receive and collect the data The comparison of the options we considered is below Ease of setup and use are our primary concerns Results ThingSpeak ThingSpeak is an open API and allows for real time data collection Users sign up for an account They can create a channel for each node in the system Data is presented graphically with respect to time Each channel can have multiple field which can collect data from multiple sensors The data can then be exported as a CSV A huge benefit to ThingSpeak is that is is extremely easy to setup and the user interface is simple However the API of ThingSpeak only allows
15. PRS has both analog and digital pins therefore both analog and digital sensors can be used in our system The sensors must be tested for the following e compatibility e accuracy e power consumption Approach Choosing the correct sensors for our project is key as collecting data is imperative for a wireless building monitoring system Cost accuracy compatibility power consumption and flexibility of sensors were main focuses for this analysis Results Temperature and Humidity Sensor 32 The requirements of relative temperature and humidity are met by the digital output sensor shown in Figure 21 And the circuit schematics is shown in Figure 22 Although size is not a leading requirement the size of the sensor is only slightly larger than a quarter which should reduce the cost of 3 D printing material for the sensor s case The tech specs for this sensor are the following 3 3V to 6V input 1mA to 1 5mA operating current and 40pA to 50UA standby current Therefore this sensor is compatible with both our platforms and the sensor will consume low amounts of power The sensor is capable of measuring relative humidity RH from 0 to 100 and has an accuracy of 2 RH The sensor also has a temperature range between 40 C and 80 C and has an accuracy of 0 5 C Therefore this sensor fulfills the accuracy requirement from our client Every measurement taken requires storage of 40 bits Our client specified that a measuremen
16. SEED Group 20 Wireless Building Monitoring System for Energy Audits Team Micah Botkin Levy mbotkini uvm edu James Chin jmchin uvm edu Hao Hu hao hu uvm edu Kaitlyn Mayberry kmayberr uvm edu Michael Zonnenberg mzonnenb uvm edu Mentor Mads Almassalkhi malmassa uvm edu Client Ethan Goldman egoldman veic org Efficiency Vermont The UNIVERSITY Efficiency Vermont of VERMONT To Ethan Goldman From SEED Team 20 Micah Kaitlyn Kimmy Hao Michael Date May 4 2015 Our team was tasked to create a Wireless Building Monitoring System for Energy Audits for Efficiency Vermont With financial support from our client we were to design and create such a system In this report you ll find our problem statement and how we went about solving it Along with an analysis section of our design Table of Contents 1 Problem Statements dit ia pages 2 5 1 1 Motivation 1 2 Problem Statement Iterations 1 3 Key Objectives Design OVERVIEW 5 cdvateracesenncarueycednidcabeseqcaneedancecendncpeutedecaueseugenceacrdede pages 2 5 Objective Analy iS 20 id pages 6 11 3 1 Objective Tree 3 2 Aggregate Rank Analysis 3 3 Metrics 3 4 Objectives Results Function ANalySiS ooooococcccccccocncncccononcnconona eee ease eee a teens ee ea eae anna ncninncn pages 13 15 4 1 Black Box Function Diagram 4 2 Functions Mean Tree 4 3 Requirements 4 4 Functions Results Design Det oo dt pages 16 18 5 1 Node Design 5 2 Syst
17. ace for both our client and their customers In order to achieve this we tried to make the node as simple to use as possible once it was constructed The setup performed by the Efficiency Vermonts employee is simple and does not take much time We implemented a Java GUI running on an SD card which allows the client to enter information about where the node is being deployed as well as the important information of connecting to a thingspeak account Once they have made an account all they have to do is plug the SD card into the Arch GPRS and flip the power switch to start the program Initially the node will enter a debug mode where it will transmit data every 30 seconds for 15 minutes in order to make sure it is working correctly Once the building manager receives the package with the node all they have to do is install the node according to Efficiency Vermont s instructions using the multiple attachment methods on the case and flip the switch to start transmitting Using an easy to use GUI and a configuration file we were able to create a simple user interface and meet this requirement 3 Reliable Our design must be reliable to be able to troubleshoot any problems deal with outages and last for multiple installments We designed two specific ways of troubleshooting the system The first is the debug mode built into the code For the first 15 minutes the node will send data 14 every 30 seconds to make sure it is transmitting correctly The sy
18. analysis as well We also estimated the amount of data we are transmitting Results Cellular Network Cellular network is a system with higher capacity The smaller the size of the cell the greater the number of concurrent users A cellular network is also a more stable system For small cells there is limited interference while for huge cells there are a number of interfering signals Also since cellular systems are decentralized they are more robust against the failure of single components This is because if a cell tower fails then another tower can pick up the signal whereas wi fi network is weaker because the router can fail and in turn the entire network will fail Wi Fi Network Compared with cellular network the wireless nature of such networks allows users to access network resources from nearly any convenient location within their primary networking environment Users connected to a wireless network can maintain a nearly constant connection with their desired network as they move from place to place Wi fi has strong adaptability which is exactly what we need for our system to work on a variety of buildings and environments Initial setup of an infrastructure based wireless network requires little more than a single access point On the other hand wired networks have additional cost and complexity as they have physical cables being run to numerous locations Our customers will need their routers to build their own wi fi network
19. bleshoot to fix this error Cost Effective Our finalized total system cost must be 1000 and must last five installations These constraints are in place to make sure our system will be cost effective to employ To test whether or not our system will last five installations we will simulate the conditions of shipping and packaging our final system multiple times to ensure our system works properly Simple Set Up Our system will be set up by someone with rudimentary or no training at all To accomplish this task we will create written and or online instructions Testing whether someone can set our system up we will perform multiple trials on a test group and improve our instructions until our system can be simple enough to set up by almost anyone Easy to Ship Our final product must be easy to ship To test this we must make sure our final product can fit into the dimensions of a package 4 4 Function Results 19 5 Design Details 5 1 Node Design Our node design is shown in Figure 10 below Figure 10 Node design Each node contains the following parts e Arch GPRS V2 Development Board and cable e Breadboard and wires e DH22 Temperature amp Humidity Sensor e TEMT6000 Ambient Light Sensor e Vodafone Sim Card 5MB mo for 2 yr e 4GB MicroSD Card e DS1307 Real Time Clock Module e 6Ah Polymer Lithium lon Battery e Li Po Rider Battery Charger e 3D Printed Case with screws and nuts e Velcro 20 Figure
20. casing the logical next step was to research materials to print with Our team quickly narrowed materials down to two options PLA plastic or LAYWOO D3 PLA plastic is a very common 3D printing material It is odorless low warp and one of the more eco friendly 3D printing materials PLA was chosen due to its strength and that it is available in a wide range of colors which was necessary for the aesthetics LAYWOO D3 was chosen as it was the most visually appealing as well as being made of recycled wood It has the ability to be cut painted and sanded It is even possible to give printed parts a wood grain appearance by varying the temperature during printing Following our material choices our team set out to design the casing using Onshape Using a caliper for accurate measurement we measured all components of the system to get a sense of how large the case had to be as well as making sure all components would fit inside the case For our first case iteration we designed a rectangular box with a removable lid Screws and nuts were used to secure the lid when the case was closed The case was printed with PLA plastic The battery was placed in the bottom of the case the Arch GPRS V2 on top of it and the additional hardware above the Arch The case had slots for the following components three sensors microSD card LED battery charger computer cord and antenna Our cases were printed using a Flashforge Creater Pro 3D printer which was accura
21. de scanners POS HID Magnetic Stripe Reader Printers F Proximity devices a RAM Disk drives v Sound video and game controllers gt Storane controllers c Have Disk d Browse select file downloaded in Step 1 gt OK Create mbed account 1 Go to https developer mbed org 2 Click the Login or Signup button in the upper righthand corner 3 Click the Signup button to create an account VEIC Step By Step Existing Node Documentation Create ThingSpeak account 1 Go to https thingspeak com 2 Click on the Sign Up button in the upper righthand corner 3 Fill out information and click the Create Account button 4 Create New Channel Help Name Created Channel 30279 2015 03 16 Private Publis Setings APIKey Data Import Export Channel 30713 2015 03 19 Private Public Setings APIKey Data Import Export 5 Click Channel Settings tab 6 Enter Fields for each sensor DHT sensor has two fields Temperature and Humidity 7 Click Save Channel 47 Percentage Complete 15 Channel Name Description Metadata Tags Latitude Longitude 34045 arch gprs Elevation Make Public URL Video ID Field 1 Field 2 Field 3 Field 4 Field 5 Field 6 Field 7 Field 8 8 oJ Click the API Keys tab and copy the Write API Key Configure the Arch GPRS V2 CJ ThingSpeak cramels Apps 48F6UGYH4C3RNI29 Write API Key Read API
22. em Design 5 3 Casing Design AN E dt a OE e pages 25 42 6 1 Microcontroller 6 2 Sensors 6 3 Logging and Buffering Data 6 4 Transmission of Data 8 9 6 5 Data Collection and Live Stream TestReEs US ii e woot RAG Conclusion and Future Work ooococcccccccococncnccccncocococncncnccncnnnancncnnnnnnnnnnnnes page A AS eats Appendices A Users Manual B Budget C D Schedule Bill of Materials 1 Problem Statement 1 1 Motivation Currently Efficiency Vermont sends energy auditors to buildings to set up wired monitoring systems There is not an easy way to remotely monitor the collected data which sometimes causes auditors to discover months later they have been collecting inaccurate data This method requires lots of travel and troubleshooting time of Efficiency Vermont employees 1 2 Problem Statement Iterations From the goals and requirements provided to us by our client Efficiency Vermont we came up with our initial problem statement Vermont Energy Investment Corporation would like a low cost building monitoring system to support their energy efficiency analysis before and after efficiency measures are implemented The system will transmit data from sensors through a gateway hub to a remote server using a mesh network that can cover 20 000 sq ft In case of a network interruption the sensor must buffer and pre process data and the gateway must be able to log data for 3 months The system must be batter
23. er and a supply current of 0 5 3mA The sensor is also under the size of a quarter which helps our size requirement At a cost of 2 90 per unit the sensor is low cost Figure 23 The light level sensor http www seeedstudio com depot Grove Light SensorP p 1253 html 34 Figure 24 shows the typical setup of the light level sensor There are only two extra necessary parts to set the sensor up which include one resistor and a microcontroller Figure 24 The light level sensor circuit schematic 6 3 Logging and Buffering Data Problem Since our wireless building monitoring system will be exposed to a variety of environments it is very possible that it could experience a network interruption As a preventive measure our client has requested that the node must be able to log data for 12 months Data will be logged at 5 minute intervals We needed to analyze the methods in which data could logged for our system Approach Our system must use a microSD card to log data from the Arch GPRS V2 We need to estimate how much data the system will be logging in order to purchase the correctly sized microSD card We needed to explore several online platforms that could be used to log our data The online platform must be able to take data that is transmitted through a cellular connection The data 35 must be displayed in a manner that is easy for Efficiency Vermont and the building monitor to observe Results We firs
24. estamp the data so that it can be backed up on the microSD card The module includes a small CR1225 Lithium coin cell battery that will run the RTC for a minimum of 9 years 17 years typical without any external power supply Figure 15 The 6Ah polymer lithium ion battery from Sparkfun Electronics The 6Ah polymer lithium ion battery consists of a triple pack of very slim extremely lightweight batteries Each cell outputs a nominal 3 7V at 2000mAh The three cells have been matched for internal impedance and can be fully charged and discharged in parallel The entire battery is rated to 1A continuous discharge The Vodafone sim card and microSD card are placed in the Arch GPRS V2 s respective slots The DH22 temperature amp humidity sensor the TEMT6000 ambient light sensor the DS1307 real time clock module and the battery are connected to the Arch GPRS V2 Some connections require a breadboard and wires The system fits inside the 3D printed case The battery is placed in the bottom of the case and the Arch GPRS V2 board rests on top of it There are slots in the side of the case for the sensor wires to fit through as well as the microSD card Velcro is attached to the case for easy attachment to surfaces The total cost estimate of a node is 288 28 23 5 2 System Design Through a cellular connection each node transmits data to a ThingSpeak API as diagrammed in Figure 16 Cellular o ThingSpeak API EN CAA e
25. for one timestamp of sensor data to be sent at a time GroveStreams is another platform that could be used to collect store and visualize data lts open API allows you to send millions of streams of data to their cloud based system Each Arch GPRS V2 can send streams or a point stream at a fixed interval Data streams can be sent at up to 10 second intervals with up to 10 individual data points Up to 94 000 000 data points per stream can be stored in a secure reliable big data cloud network three years of 1 second resolution data Data can be downloaded for additional back up or off line analysis GroveStreams provides customizable charts and graphs to visualize data It also has notification tools to alert you to take action when predefined or user defined events occur These notifications can be in the form of text email HTTP calls and GroveStream platform messages 38 Xively is a third platform option that allows developers to connect sensor derived data It provides internet of things connectivity that is fast secure and scalable In a single interface connected users are able to manage their connected devices and their data Users create a Xively account add their device and channels import the Arch GPRS V2 s program and customize the sensor labels Sensor values are displayed in channel graphs How This Impacts Our Design Ideally we would have used Xively since it has some documentation with the Arch GPRS already and fits
26. h Speed Chip Computer a Disk drives KK Display adapters Os Human Interface Devices C IDE ATA ATAPI controllers Z Imaging devices amp Keyboards Lenovo Vhid Device PY Mice and other pointing devices E Monitors AP Network adapters lb Other devices jp Unknown device Y Ports COM amp LPT I Mbed Virtual Serial Port COM3 a Print queues BB Processors i Sensors Software devices Sound video and game controllers E gt Storane controllers Add a legacy non Plug and Play device to the computer a Install the hardware that manually select from a list Advanced gt Next a Device Manager File Action View Help es Bm e Add Hardware The wizard can help you install other hardware The wizard can search for other hardware and automatically install it for you Or if you know exactly which hardware model you want to install you can select it from a list What do you want the wizard to do Search for and install the hardware automatically Recommended 8 Install the hardware that manually select from a list Advanced ba Owes b Ports COM amp LPT gt Next a Device Manager m File Action View Help e m U m amp Add Hardware From the list below select the type of hardware you are installing If you do not see the hardware category you want click Show All Devices Common hardware types KP Network adapters a BSJPCMCIA adapters E Portable Devices POS HID Barco
27. ics and Communication Technologies INTERACT 3 5 Dec 2010 350 355 lt http ieeexplore ieee org xpl articleD etails jsp tp amp arnumber 57061 78 amp contentT ype Co nference Publications amp gt Anbya M F B Salehuddin M Hadisupadmo S amp Leksono E Wireless sensor network for single phase electricity monitoring system via Zigbee protocol Control Systems amp Industrial Informatics ICCSII 23 26 Sept 2012 261 266 lt http ieeexplore ieee org xpl articleDetails jsp tp amp arnumber 6470512 amp contentT ype Co nference Publications amp gt Billions and Billions ThingSpeak N p n d Web 20 Apr 2015 lt https thingspeak com gt BuildinglQ Solutions BuildinglQ N p n d Web 21 Sept 2014 lt http Awww buildingig com solutions gt Data Validation Algorithm for Wireless Sens Networorks Hindawi Ed Yu Gu International Journal of Distributed Sensor Network 2013 Web 01 Oct 2014 Fawzy Asmaa Outliers Detection and Classification in Wireless Sensor Networks Science Direct Elsevier July 2013 Web 01 Oct 2014 Figo Davide Preprocessing Techniques for Context Recognition from Accelerometer Data Personal and Ubiquitous Computing 14 2010 645 62 Instituto Superior Tecnico 2010 Web 1 Oct 2014 Mcouat Joanna Wireless Sensor Networks Google Books Springer Science 23 Oct 2013 Web 01 Oct 2014 Nikola Janjic Technical Reference User Manual TRM Measure Savings
28. it data from the gateway to a remote server through a cellular connection He also suggested that we look into using Pinoccio as a way to communicate data from multiple sensor nodes to a main hub node Our client explained that the system should cost approximately 1 000 and last at least 5 installations to be cost effective Our problem statement was continuously refined as we conducted in depth analysis on various aspects of our system and continued to meet with our client We learned that our client needed the sensors to buffer data for 2 weeks and the gateway must be able to log data for 12 months at 5 minute intervals Also we narrowed down the list of sensors that our system should incorporate to include relative and external temperature humidity magnetic field sensors and generic 0 5V and 4 30mA inputs With a deeper understanding of the web based admin interface we updated the problem statement to include its ability to locate the problem area configure network connectivity troubleshoot network connectivity and check values for validity Our problem statement at the end of our first semester is presented below Vermont Energy Investment Corporation would like a reliable building monitoring system to support their energy efficiency analysis before and after efficiency measures are implemented The system will transmit data using a mesh network that consists of remote sensor devices connected to a gateway hub which can cover an area of
29. ly appealing and that can be secured anywhere inside a building This objective is of the utmost importance as our client has stressed that if the system does not look professional or visually appealing the customer s will not be interested in the finished product Alongside this idea is that the case must be user friendly The user must be able to turn on the system easily with the power switch insert the microSD card into the Arch GPRS V2 with ease charge the battery without opening up the case via mini USB and upload code to the Arch GPRS V2 without opening up the case Finally the case must be secured anywhere inside a building while being the least intrusive or damaging to the building Approach Our team wanted to make our casing design easily improved or edited as well as being easily manufacturable Therefore the choice was to design our case using Onshape a cloud based 3D CAD system and 3D printing Onshape was chosen because of its versatility It is the first and only full cloud 3D CAD system This is beneficial because not only can you pull up and edit a model from any computer but you can also corroborate and improve your design with others Thereby Onshape helped reduce the time necessary to complete our 3D modeling of our casing 3D printing was chosen because the technology is readily available to produce our cases quickly with a high level of precision 26 Realizing that our team was going to use 3D printing to make our
30. n along with the API key found on their ThingSpeak channel Once the GUI is compiled text files will automatically be created on the card and once the microSD card is inserted into the node and the power switch is toggled to the on position the node will start transmitting the selected data Data will be transmitted and stored every at 5 minute intervals Cellular fork ThingSpeak API sensors nate Figure 1 Design utilizes sensors connected to nodes which communicate collected data to a gt amp 43 b 3 wa ThingSpeak API via a cellular network 3 Objective Analysis 3 1 Objective Tree Our team had five higher level objectives for our wireless building monitoring system for energy audits low cost ease of use reliable adaptable and easy to ship An objective tree was created with these constraints shown in orange First the total system must cost approximately 1000 to be cost effective for Vermont Energy Investment Corporation Low cost Total cost 1 000 Figure 2 Low cost portion of the objective tree Second the system needed to be easy to use This meant the data collected is readily accessible for Efficiency Vermont Also the system must be easy for both Efficiency Vermont and the customer to set up and maintain Access to data Simple set up by Efficiency Vermont Ease of use Simple set up by customer Minimal system upkeep required of customer Online database Fed by Arch
31. nd the outputs will be sensor data in the cloud as well as outage alerts if necessary 4 2 Functions Mean Tree To completely understand what our system needed to do and how our team was to accomplish this we created the functions mean tree shown in Figure 9 Gather and transmit data cane Send data to Send data to Send outage environment Buffer data Log data Check for outage 8 A A Gateway remote server alert information Wireless m Transducer Internal storage i esh Internal storage Cellular network network Wireless stand Send to local alone sensors computer Figure 9 Function Mean Tree where blue boxes represent functions and white boxes represent Continuous monitoring of means of our system As shown above most of the subfunctions only have one or two means since they are limited or constrained by the problem statement Two notable subfunctions are how the data will be sent to the gateway and how the data will be sent to the cloud and remote server Our team is planning on setting up the sensors in a mesh network that would relay the data to the gateways However we are also exploring the option of having standalone sensors that send the data to the gateway or even directly to the cloud Our client has specified that a cellular connection 17 between the gateway and the cloud is prefered however we are also exploring the option of having an addition connection opportunity through the use of WiFi
32. on Results 29 Our group analyzed the following aspects of our wireless building monitoring system for energy audits Microcontroller Sensors Logging and Buffering Data Transmission of Data a fF ON Data Collection and Live Stream The following is a Summary of the problems we each analyzed our approaches our results and how these findings impact our design 30 6 1 Microcontroller Problem We need a microcontroller system to connect with sensors and other hardware to collect environmental data It needs to utilize a cellular connection to send data It must have the appropriate sleep functions and battery capability to last at least 3 months on a single charge Approach We researched various platforms that could be used in our system It was important to consider how compact they are how they would connect with sensors and other hardware and their cellular capabilities We also looked for the abundance of documentation and libraries Results Arch GPRS V2 is the new improved version of the Arch GPRS development board from Seeed Studio It is an mbed enabled development board that houses a cellular networking module along with a microcontroller The Arch GPRS V2 uses the LPC 11U37 microcontroller instead of the LPC11U24 used on the Arch GPRS You can use the mbed C C SDK libraries and optimizing online development tools to rapidly build your prototypes mbed is a platform and operating system for the internet
33. or battery power consumption Figure 28 above shows the current being drawn from the battery when our device goes from sleep mode waking up collecting environmental data turning on the SIM900 module sending data to ThingSpeak turning of the SIM900 module and then going back to sleep When in sleep mode the system is drawing about 8mA If our system is only in sleep mode it will last 750 hours 6 000 mAh 8mA 750 hrs which is about 1 month of usage For our system to meet our objective of lasting a minimum of 3 months we must perform further R amp D to have our sleep mode enter a deeper sleep of about lt 2mA 42 7 5 Data Usage Analysis For our system we bought a data plan that has 5MB month In order to make sure we had enough data to transmit every 5 minutes we divided the month into number of transmissions Total Number of Transmissions per Month 30 days x 24 hours day x 12 transmissions hour 8 640 Then we divided the monthly data limit by the number of transmissions Maximum Data U sage per Transmission 5x10 Bytes 8 640 578 70 bytes Assuming that we are not using more than 500 Bytes per HTTP request that we send to ThingSpeak we have plenty of data 8 Conclusion Our system does not meet the objective of lasting at least 3 months on a single charge even with our large 6Ah lipo battery To upload the data to thingspeak our system had to turn on the SIM900 module connect to the cellular network send
34. ot only does our system need to work consistently day to day but it also needs to respond to problems it may encounter such as outages Ease of use and adaptable were very close in ranking as the next highest ranked The system needs to be simple and work in a variety of buildings and environments Through conversations with our client we determined that low cost should be achievable as long as the system is simple Easy to ship isn t so much of a priority for our team as it should come along with the simple design 12 Objective Ease of Reliable Adaptable Low Cost Easy to Score Use Ship ee isos SS E AC I a ee Se TS Lae Et O PI EE Table 2 Aggregate ranking of higher level objectives EZ HOMER ESE ma e 3 3 Metrics There were several metrics we utilized to quantify the achievement of our objectives The total system must be low cost approximately 1 000 In order to measure this we added up costs including parts labor and shipping To ensure that our system is easy to use we needed to make sure that it met the needs of our client as well as the customers using the system We had our client setup a node and access its data to judge how easy it was compared to the system they currently use Ideally this system will be more user friendly than their current system We also had several people of various backgrounds use our step by step instructions to setup a node This tests how easy it is for building users to set up nodes
35. r client to change some of the requirements for our system We switched to using the Arch GPRS V2 instead of Pinoccio We wanted to send our sensor data through a cellular connection rather than wi fi and the Arch GPRS V2 development board houses a SIM900 cellular networking module It also has a built in microSD slot for convenient data backup Using the microcontroller s low power ARM Coretex MO Core we needed to make the Arch GPRS V2 last 3 months on battery power Here is our final problem statement Efficiency Vermont would like a reliable building monitoring system to support their energy efficiency analysis before and after efficiency measures are implemented The system is made up of multiple nodes each of which contain sensors and a battery connected to a microcontroller The microcontrollers must last 3 months on battery power Collected data is fed into an online database through a cellular network capable of covering an area of 20 000 sq ft In case of a network interruption the microcontrollers must buffer data for 2 weeks and the online database must be able to log data for 12 months both at 5 minute intervals The system is packaged with step by step instructions and mailed to a customer with rudimentary training for easy setup It will have the ability to collect data from a variety of compatible sensors relative and external temperature humidity and magnetic field sensors as well as generic 0 5V and 4 30mA inputs which will be
36. re eal Time Clock Module SB LiPoly Charger 51 95 7 80 ED RGB Clear Common CathodSparkFun 1 50 3 00 Mini Power Switch Grove DHT22 s2990 59 80 401 Sparkfun Real Time Cock 54 95 4 95 12 18 Solderable Breadboard SparkFun Oo ol lolol 8 97 rs2s0 750 3microUS8 cable seeedstudio Esso 1770 8rove Temp Humi Sensor seeedstudio soso 19 80 DiotaiLioht Sensor seeedstudio 426 2130 0 00 Micro SD card famazon 0 98 soa ora Tminiusb cable monoprice 54399 8798 1039 months fembeddedworks net s4995 9990 3102 ArchGPRSV2 seeedstudio stgo 2980 SensorPro seeedstudo seso 1980 Polymer Lithiumion Battery seeedstudio soso 950 tipoRier battery charger seeedstudio ssas 495 3036fSensor Spaun Estas 79 Menasma Sparkrun soso 200 Momentary PushButon Swich SparkFun soss 190 HalEffectSensor SparkFun s385 11 85 Arduino and Breadboard Holde SparkFun siso aso sso aso 52495 2495 saos 1485 sass 2085 sss s5 soss P 190 so 53205 6590 SMR HS OO OO CO CO CON BIR RS RK TMM RH MLN ho eo Go pum Go Go 12 18 12 18 cla eo oa o ela o E mo g 5 g m 14 95 0 95 3 90 15 00 39 99 1 50 32 95 54 95 50 95 14 95 14 95 1 95 1 50 an Above you will find o
37. stem will also write any errors that happens while running to an error log file on the SD card Each error did not connect to the network for example will be written to the txt file with a timestamp Our system also writes every value it reads onto the SD card to a csv file so it can be accessed after in case of an outage The system is able to last five installations due to the configuration file and reliable parts However we had some problems getting the battery life to last 3 months As seen in our analysis it will not last that long We were able to most satisfy this objective with our project 4 Adaptable The system must be adaptable to work in a variety of buildings There were two parts to this objective variety of sensors and connection in a range of locations Since we choose to use a cellular network to transmit data there will be some buildings that do not get a connections and will not be able to transmit However the system was able to transmit in all the buildings that we tested We were only able to get the temperature humidity and light sensors to work We were hoping for a larger range of sensors However the light sensor is plugged into a analog input so the system could be configured for any sensor with an analog For the most part we were able to meet this objective 5 Easy to Ship Our system had to be able to be shipped in the mail to reduce the travel of Efficiency Vermont employees We were able to achieve this objec
38. t should be taken every 5 minutes and will need to be kept for a maximum of 12 months Therefore the approximate storage needed for this one sensor is approximately 4 3 megabytes After looking at a variety of temperature and humidity sensors this seems to be the best fit for our project due to low cost 9 95 per unit and accuracy Figure 21 The temperature and humidity sensor https www sparkfun com products 10167 Figure 22 shows the typical setup of the temperature and humidity sensor which consists of two parts the sensor itself and the microcontroller 33 Pin sequence number 123 4 from left to right direction Figure 22 The temperature and humidity sensor circuit schematic Light Level Sensor The requirement to measure light level is met by the digital output sensor shown in Figure 23 And the circuit schematics is shown in Figure 24 The sensor works by varying its resistance depending on the amount of light the sensor is subjected to The resistance will decrease as the light level increases In bright light the resistance will measure 20KQ In the dark the resistance will measure 1MQ The output of the sensor will be HIGH in bright light and will be LOW in the dark Our client only wishes to know if the light is on or off therefore this sensor meets the accuracy requirement of our project The sensor is compatible with both of our platforms and consumes a low amount of power The sensor requires 3 5V pow
39. t looked at how much data we will be storing at any one time for an Arch GPRS V2 with all sensors attached Data will be collected at 5 minute intervals for 2 weeks Supposing each data point is an integer and is 4 bytes from each of our sensors and we are collecting data from 3 sensors plus a 14 byte timestamp then we would need the following minimum storage 12 months PLE a ae 518 400 minutes of data logged by each sensor 518 400 minutes 26 bytes of data ramos 2 695 680 bytes of total data collected This means that for logging data we would need a minimum of 2 696 MB of storage How This Impacts Our Design We decided to purchase a 4GB MicroSD Card for each Arch GPRS V2 Since microSD cards with large amounts of capacity are very cheap today this seemed to make the most sense This will allow for data being logged for more than 12 months at a time Also there will be plenty of space in case the mircoSD card is not cleared before a new installation 6 4 Transmission of Data Problem Our system needs to be able to cover an area of 20 000 sq ft reliably We need to make sure that the amount of data we are transmitting can be handled by the network We explored two options for transmitting data through a cellular network and a wi fi network Approach 36 We first looked at the stability of each system and then how robust they are against failures Adaptability and cost were other important factors to consider in the
40. te enough for our design Following our first case iteration we attempted to use the LAYWOO D3 material Yet the material was harder than expected to print as the material would easily crack Our team was unable to get the temperature just right for the material therefore we abandoned it for the PLA case which was already exceptional We considered various methods to attach the case to the wall velcro zip ties and adhesive strips Each attachment has its benefits and drawbacks If we went with the velcro approach we would attach one side of the velcro to the case and have the user attach the other side of the velcro to the surface where they wanted the case to be mounted It would be simple for the user to take the case off of the wall mount however it would be very difficult to take the velcro off of either the case or the wall If we used zip ties we would need to print hooks on the case for them to attach to The zip ties would then need to be wrapped around pipes or similar building features This method would limit the surfaces the case could be mounted to The third option would be to attach the case to the wall surface using adhesive strips These are slightly less 27 strong than velcro but would still be able to hold the node s weight They are fairly easy to peel off surfaces when they are no longer needed Results Our team wanted to make our final case user friendly visually appealing durable and practical Therefore
41. the data through a HTTP request and then power down the SIM900 These maneuvers to upload data were very expensive in terms of power consumption To combat this issue one solution would be to upload large amounts a data once a day instead of the 288 uploads we are currently performing We were limited doing this approach by using ThingSpeak so we would need to find another viable loT online database that can handle bulk data uploads Another issue with our power consumption was the sleep mode our system entered was only able to reach as low as 8 mA In order for us to have reached our goal we would need our sleep mode to reach sub 2mA A third way to combat the power consumption issue would to use the strategy of dead band compression Dead band compression is when we would not upload equal consecutive data this would decrease the number of uploads per day and save power In conclusion we ve met most of the important objectives and in the end created a low cost monitoring system that will last about 30 days on a single charge 43 9 References 3D Printer Filament Comparison MatterHackers N p n d Web 20 Apr 2015 lt http Awww matterhackers com 3d printer filament compare gt About Us PanStamp N p n d Web 21 Sept 2014 lt http www panstamp com about us gt Akshay N Kumar M P Harish B amp Dhanorkar S An Efficient Approach for Sensor Deployments in Wireless Sensor Network Emerging Trends in Robot
42. tive by creating a compact and durable casing for the node that would be able to be shipped 15 4 Function Means Requirements Analysis 4 1 Black Box Function Diagram To get an idea of our project our team used the black box and expanded black box shown below in Figure 7 and Figure 8 These black box diagrams gave us an idea of what our inputs to the system were what functions our system will perform and what the expected outputs are Gather and Transmit Data Battery Power Outage Alerts Figure 7 Black Box Diagram Log data Stored sensor data send Dato as Check for outage Send outage alert Outage alerts Gateway remote server Web admin interface Buffer data Stored sensor data Gather environment information Figure 8 Expanded Black Box Diagram Key Functions 16 The most significant function is to gather environmental data from the building that is being audited To do this our system will use the following sensors temperature humidity magnetic field voltage and current Each sensor must buffer data incase of a connection outage and will be able to send the collected data through a mesh network to gateway The gateway will be the hub of the entire system it will collect the data from the sensor nodes in the mesh network data log incase of connection outage and transmit the data to the cloud via cellular or wifi Overall our system will take the environmental information and battery power as inputs a
43. ur total budget for the project We ve spent a total of 1 619 94 which is less than 35 of our 5 000 budget C Bill of Materials Below you will find the our bill of material for one node Qty Component Vendor Price 1 Arch GPRS V2 SeeedStudio 49 95 1 Grove Temp amp Humidity Sensor SeeedStudio 5 90 1 5mb Monthly SimCard for 60 months EmbeddedWorks 43 99 1 TEMT6000 Ambient Light Sensor SparkFun 4 95 1 6Ah LiPo Battery SparkFun 32 95 1 USB LiPoly SparkFun 14 95 1 Real Time Clock SparkFun 14 95 1 SPDT Mini Power Switch SparkFun 1 50 1 RGB LED SparkFun 1 95 1 micro USB cable monoprice 0 98 1 mini USB monoprice 0 74 1 4GB microSD card amazon 4 26 1 3D printed Case 3D Hubs 75 00 Total 252 07 D Schedule The figure shown below is our team s Gantt chart which shows our schedule plan over the of the design 50 52
44. we designed and printed a compact case that encompasses all of these ideas well Using PLA we printed the case shown in Figure 18 below We are presenting to our client velcro zip ties and adhesive strips as possible methods of securing our casing to the customer s building a b Figure 18 The bottom of the casing for the system The battery is rested on the bottom of the case with the Arch GPRS V2 resting on top of the battery The Arch GPRS V2 is then fastened with screws via the bottom through holes to secure both it and the battery Note there is a slot for the microUSB on a to the left and there is a microUSB slot on b in the center 28 a b Figure 19 The top of the casing for the system There are a total of nine through holes for this part eight of which are for fastening both the bottom of the case to the top as well as the mini USB battery charger and the other larger hole is for a LED indicator The center cut shown in a is for a mini USB to be plugged in with ease Note all edges are smooth for aesthetics in b a b Figure 20 The total assembly of the case In a you can see the on the top left a slot for the power switch and on the top center the slot for the mini USB charger In b you can see the three rectangular holes for the sensors to go through to sense their environment as well as two through holes on the side to secure the antenna of the Arch GPRS V2 6 Analysis Modeling Simulati
45. y 10 The system must also be adaptable Data is collected from a variety of sensors relative and external temperature humidity magnetic field sensors and generic 0 5V and 4 30mA inputs The system will be utilized in a variety of buildings and must cover an area of 20 000 sq ft Relative and external temperature Humidity Collects data from a variety of sensors Magnetic field Adaptable Generic 0 5V and 4 30maaA inputs Can cover an area of 20 000 sq ft Works in various buildings Figure 5 Adaptable portion of the objective tree Lastly the system must be easy to ship therefore it must be compact lightweight and durable Compact Easy to ship Lightweight Durable Figure 6 Easy to ship portion of the objective tree 11 3 2 Aggregate Rank Analysis Each of our team members and our mentor performed a ranking of our five higher level objectives low cost ease of use reliable adaptable and easy to ship presented in section 2 1 A ranking of 1 was the most important and a ranking of 5 was the least important The individual results are listed in Table 1 below 1 5 EN Easy to ship Easy to ship Easy to ship Easy to ship Easy to ship Easy to ship Table 1 Individual rankings of higher level objectives From these individual rankings an aggregate ranking of our five higher level objectives was compiled shown in Table 2 As a team we gave reliability the highest score N
46. y powered last up to 3 12 months and transmit at 5 min intervals The system will be set up by an energy auditor with rudimentary training and have the ability to collect data from a variety of sensors including temperature humidity light level air quality occupancy motor state voltage current and serial inputs The hub should provide data to a web admin interface which allows for configuration and troubleshooting of all parts of the system The remote server should be able to collect data as well as be browsable and able to send alerts for initiating troubleshooting when faced with a connection outage After creating our objective tree and performing rank analysis we updated our initial problem statement to reflect new information and ideas we came up with during these processes Through rank analysis we found that reliability was the most important objective for our team To emphasize reliability we included it in the opening sentence of our problem statement Ease of use was our second highest ranked objective therefore we included it in our section on the system setup We also wanted to highlight that the system wouldn t always be set up by an energy auditor but a person with rudimentary experience as well During our first meeting our client Ethan Goldman provided us with important requests and requirements for our project from which we were able to refine our problem statement We learned that he would prefer the system to transm
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