Implementing smart White LED Lightning system in buildings using
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1. proportional to light intensity Since the graph is linear we are able to implement PWM on these White LED panels In Graph 3 the power consumed by the panel vs light intensity is plotted It is observed that the light intensity is more at less power and it becomes constant at high power input B Driver Circuit for White LED down panel The each GPIO General Purpose Input Output pin of the LPC2148 microcontroller can safely supply or sink a maximum of 4 mA current It would be difficult for GPIO pins to drive a high current LED DRIVER So it is not recommended to directly supply current to a LED of 20 mA or a white LED Thus the matrix form of LEDs mounted on the square panel cannot be directly linked to the GPIO pins of the LPC2148 microcontroller So it is not recommended to connect the white LED down panel directly to the GPIO pins of the LPC2148 microcontroller But a single LED of 2 mA or 5 mA can be connected directly to the GPIO pins of the LPC2148 microcontroller 421 Proc of the Intl Conf on Advances in Electronics Electrical and Computer Science Engineering EEC 2012 Fig 6 Schematic diagram of the transistors circuit as the intermediate module The figure 6 shows the basic schematic diagram of the intermediate circuit between the LPC2148 microcontroller and the white LED down panel This schematic diagram has been drawn on the Express SCH software The figure shows the use of LPC2148 as the controller2. room was selected The LED panel was placed on top of the table Imeter from floor The measuring instrument i e LUX meter is at 30 centimetres from the emitting surface of the panel and is directed towards it in the same plane The colour of the walls is white The temperature is normal room temperature at 300 kelvin The lux readings of LEDs are measured at different values of current and voltages and then compared and plotted 350 e go oD 300 p x 250 af Light 200 4 o intensity r f lux 150 i 100 olf 0 12 T T T T T T T T l 0 01 02 03 04 05 06 07 08 09 1 Current Ampere GRAPH I Light intensity vs Current 420 SEEK 359 300 4 _ 250 fF Light 209 4 7 intensity _ od nx 150 F 100 T 59 f D 7 nt T T 1 0 5 10 15 Voltage Volts GRAPH II Light intensity vs Voltage T 6 Power Watts GRAPH III Light intensity vs Power From the graph 1 it is observed that lux reading increases with increasing values of current for smaller values but tends to go constant at higher values The maximum light intensity of 326 lux is observed at 0 78 A In graph 2 values of voltage and light intensity are compared The lux readings remain zero for the voltage values up to 3 7 V At this point the first lux reading is observed and 1s called pinch off point From then the graph is linear voltage is directly
3. this holistic concept of intelligent lightning system will help in green building design with low carbon footprints and thus harmonious to nature ACKNOWLEDGMENT The authors are highly grateful to their respective organisations for their help and support REFERENCES 1 Hongming Yang Tim C W Schenk Ashish Pandharipande Enhanced Illumination Sensing Using Multiple Harmonics for LED Lighting Systems IEEE TRANSACTIONS ON SIGNAL PROCESSING VOL 58 NO 11 NOVEMBER 2010 2 Luigi Martirano Lighting systems to save energy in educational classrooms DIAEE Electrical Engineering Area Rome Italy 3 Hui Ren Kai Zhou Zhen Li Hui qin Wang Research and realization of new stage lighting control system 2011 Fourth International Joint Conference on Computational Sciences and Optimization 4 A B Sebitosi and P Pillay White LEDs for rural lighting 5 Narendra B Sonismember IEEE and P Devendra The transition to LED illumination A case study on energy conservation 6 Chapter 16 PWM LPC214X user manual by NXP founded by Philips 7 Chapter 8 GPIO user manual by NXP founded by Philips 8 PIR Sensors Ramandeep Singh is currently working as an assistant professor in EECE department in ITM University Gurgaon He received his M E in embedded systems from BITS Birla Institute of Technology and Science in 2009 He completed his B Tech in Electronics and communication from GTBIT Guru T
4. 0000000 prescalar register disabled PWMMCR 0x00000002 resets on PWMO PWMPCR 0x00002000 enables PWMS5 PWMMRO 0x000000ff PWMTCR 0x00000009 enables PWM PWMLER 0x00000021 latch new match entries while 1 infinite loop PWMMRS5 0 _ _ set PWMS duty cycle at fixed freq PWMLER 0x00000021 delay 9 PWMMRS5 255 set PWMS duty cycle at fixed freq PWMLER 0x00000021 delay 1 int main PWM calling PWM delay 1 calling delay function while 1 disable infinite loop The above code shows the implementation of the PWM on the LPC2148 microcontroller by NXP using Keil micro vision4 software In the PWM coding implementation we have to initialize inbuilt PWM registers 7 of the LPC2148 microcontroller We define a function void PWM in which all the inbuilt registers 7 of the PWM module are initialized to perform a specific task In void PWM function PWM output 5 PWMMRS is taken to observe the Pulse Width Modulation of the LPC2148 microcontroller as the other PWM output channels share their pins as UARTO and UARTI PWM1 PWM3 PWM4 PWM6 and PWM2 shares with IRQ EINT2 and can also be SEEK configured as the GPIO pins So PWMS5 output channel is left which shares pin P0 21 with only general purpose input output GPIO pin The while 1 loop defines the infinite loop which keeps on executing the PWMS to give the Pulse Width as the output on pin P0 21 In while 1 loop PWMLER Pulse W
5. Implementing smart White LED Lightning system in buildings using 32 bit microcontroller Ramandeep Singh Assistant Professor EECE department ITM University Gurgaon India Abstract Increasing user s comfort and reducing the wastage of our electricity power is the major objective of this paper Current designs used in building are not successful in incorporating the occupant comfort for the user and use of the power efficiently at the same time In this paper we present a novel utility based building control system that optimizes the trade offs between meeting the user comfort and reduction in the cost of operation by reducing the excess usage of energy We present an implementation of the proposed approach as an intelligent interior lighting control system that significantly reduces the energy cost Today in our lighting system for institutes and offices either incandescent lamps or fluorescent tubes are being used The luminous efficiency of fluorescent tube is 67 lux while that of an incandescent lamp is just 22 lux So LED panels are a very efficient alternative for them which have a luminous efficiency as high as 100 lux Although LED panels have initial cost but they repay it in form of their long lives This new stage intelligent lighting system has main features like the use of sensor networks to optimize the trade off between fulfilling different light preferences at different areas of building and minimizing the energy consumpt
6. LPC2148 V IMPLEMENTING PIR SENSOR This feature is again a very interesting feature and contributes a major part of energy savings as people move out of their places keeping the lights turned on or forget to switch them off In any such cases when the area is not occupied the lights will automatically switch off and if the person moves in to that area the lights will be switched on This is done by sensing the occupancy or human detection by using PIR sensors A PIR sensor is a sensor which is able to detect motion by using infrared radiations It is also called as a Passive Infrared sensor or Infrared motion sensor A PIR sensor is made of a pyro electric sensor A pyro electric sensor detects levels of radiations around it It is assumed that every living body emits some level of radiations We are not interested in level of radiations rather we want to detect presence of such radiations The sensor is split into two halves which are connected to each other through a wire in such a manner that if there is no detection of radiations the output is a LOW signal As soon as it detects any variations or movement of a radiated body from one half to another it outputs the signal as HIGH 8 A pyro electric sensor is made of a crystalline material which when exposed to infrared radiations generates electric charge The changing radiations changes voltages generated measured by the amplifier The sensor is attached with a Fresnel lens which focuses t
7. M University Gurgaon India replacements of CFL S with white LED down panels One of the ways to implement this holistic concept in a building is illustrated in this paper that will result in an energy efficient system I ARCHITECTURE AND BLOCK DIAGRAM The controlling of White LED panels is done through 32 bit ARM 7 LPC2148 microcontroller 3 Each microcontroller has a White LED panel connected to it through wires Each White LED panels contain Light sensors to detect the ambient light intensity and PIR sensors occupancy sensors to detect human presence All the data from these sensors is transmitted to the microcontroller that intelligently reads the data and compares them to control the light intensity of the LED panels This basic idea how 1 LED panel is controlled by using a single microcontroller is proliferated to control the lighting system of whole building as shown Each 4 x 1 LED panel contains 2 sensors 1 Light sensors 2 PIR sensors Each sensor independently collects data and sends it to the microcontroller For e g five such LED panels LP are designed for one room which are controlled by 1 ARM7 LPC2148 microcontroller RC Each floor has 10 rooms so 10 microcontrollers are used in each floor A floor manager FM i e another ARM7 microcontroller is connected to these microcontrollers RC which manages the room controller All the floor managers are then connected to a main server wirelessly so as to ma
8. ambient light A light sensor is an electronic device which detects and measures amount of light to which it is exposed and converts it into digital form counts and gives output via two wire I C bus for serial interface Light to digital device includes on chip photodiodes integrating amplifiers Analog to digital accumulators clocks buffers comparators and an I2C interface on a single IC The photo diodes used are responsive to visible light and their output current is boosted by amplifier which is simultaneously converted to digital value using ADC providing up to 16 bit resolution The digital value is then written into data registers converter SEEK Proc of the Intl Conf on Advances in Electronics Electrical and Computer Science Engineering EEC 2012 The ARM7 LPC2148 controller reads the register and calculates the luminance in lux Output voltage a vV light intensity Current Amplifier Output voltage a Eght intensity Figure 7 Block diagram to show the functioning of a light sensor In figure 7 the Vdd supplied is 1 8 3 3 V and Rext is 100 kQ Communication between ARM7 LPC2148 and IC is accomplished through a fast two wired I C serial bus interface compatible both the ARM7 and IC The digital output of the device is inherently more immune to noise when compared to an analog interface The final converted digital output is used by ARM7 controller to perform the dimming operation of LED pa
9. egh Bahadur Institute of Technology IP University in 2007 He got 100 scholarship in his M E Program from Philips Semiconductor Bangalore Prithipal Singh is currently a final year undergrduate student in ITM Univerity Gurgaon in EECE Department Siddharth Lalit is currently a final year undergrduate student in ITM University Gurgaon in EECE Department 424 SEEK
10. he radiations into the crystalline material The varying radiations that fall on this crystal generate the voltage which is indicated by the amplifier Element Amplifier Fresnel lens Figure 11 Working of a PIR sensor TABLE II Specifications and dimensions of PIR used 8 Model D203B TO 5 2x1mm 2 elements 5x3 8mm 5 14um 275 gt 3500mV gt 3300V W gt 14 x108 omlizi 2 W lt 70mV lt 10 0 3 1 2V 423 Proc of the Intl Conf on Advances in Electronics Electrical and Computer Science Engineering EEC 2012 Output SEEK Proc of the Intl Conf on Advances in Electronics Electrical and Computer Science Engineering EEC 2012 A Connecting PIR sensor to LPC2148 ARM7 microcontroller TABLE III Description of GPIO registers 7 NAME DESCRIPTION IODIR GPIO Port Direction Control Register controls the direction of each port pin individually The PIR module contains a 3 pin connector with power supply pins and output pin Pin 1 in supplied with 3 5 V Dc supply and Pin 3 is GND Whenever the device detects a motion or change in radiations level it outputs as HIGH IOSET GPIO Output Set Register controls the state of output pins IOCLR GPIO Output Clear Register clears the state of the output pins in IOSET signal to the pin 2 The HIGH output generated by the module is 3 3 V Dc This voltage level is not enough for the microcontroller to detect So to power up the out
11. idth Modulation Latch Enable Register is declared after the initialization of PWMMRS as it enables the new PWM match values 7 2 STRATEGIES TO IMPLEMENT PWM IN CASE OF LPC2148 ARM7 MICROCONTROLLER USING GPIO PINS void main IODIRO 0x000000ff configuring port 0 IODIR1 Oxffffffff configuring port 1 IOCLRO 0x ffffffff while 1 IOSET1 0x00000000 b IOSET1 delay 9 IOCLR1 b IOSET1 0x00000001 b IOSET1 delay 1 IOCLR1 b j j In this we have implemented the PWM using GPIO General Purpose Input Output 6 7 pins of LPC2148 to observe the output waveform in the logic analyzer of Kiel micro vision4 software It has two ports i e PO and P1 and defines the 4 basic registers that are TABLE I Description of GPIO registers 7 NAME DESCRIPTION IOPIN IODIR IOSET GPIO Port Pin value register reads the current state of GPIO configured port pins GPIO Port Direction Control Register controls the direction of each port pin individually GPIO Output Set Register controls the state of output pins GPIO Output Clear Register clears the state of the output pins in IOSET a em p i ie ben m nie aie Ge toe k ianiai Miki ie G poii 7 bel paue ut i r E Fp HT Mia N hs ee W efa ee es te bata GELA L GCS HE r p wE 1 jii wet i Ut fore Fig 10 PWM5 waveform on the logic analyzer of 10 duty cycle implemented using inbuilt module of
12. ion using sensors and controllers We further extend our approach to optimally exploit the ambient light using ambient light sensors and using dimming techniques One of the ways to implement this holistic concept is illustrated in this paper that will result in an energy efficient system Keywords White LED down panels PIR Sensors Light Sensors LPC2148 ARM 7 microcontroller I INTRODUCTION This paper concentrates on development of an efficient integrated lightning control system for a building which communicates with real world and help to save energy This is achieved by using energy saving strategies in lightning system such as 1 to replace the currently used fluorescent and incandescent lamps with energy efficient white LED down panels 2 To integrate the day light with artificial lights to attain an optimal level of luminance in the area 3 To switch OFF ON the lights according to real time occupancy of the area 2 Paper also shows results of an experiment conducted in which two identical rooms were selected For ROOM 1 with White LED down panels with occupancy detection and day light adjustment values of luminous intensity current and power were observed calculated and then compared with corresponding values of currently used CFLs in ROOM 2 The power consumption in ROOM 1 was observed to be a clear reason for the Prithipal Singh EECE department ITM University Gurgaon India Siddharth Lalit EECE department IT
13. nage the whole lighting system The data is transferred serially from one microcontroller to another At server the entire data base is collected managed and controlled wisely so supervise the working of the system Proc of the Intl Conf on Advances in Electronics Electrical and Computer Science Engineering EEC 2012 Edited by Dr R K Singh Copyright Institute of Research Engineers and Doctors All rights reserved ISBN 978 981 07 2950 9 doi 10 3850 978 981 07 2950 9 827 ai SEEK FLOOR 1 MAIN SERVER Figure 1 Building Plan Figure 2 Room Plan Driver Circuit for driving the LED LPC2148 ARM7 CONTROLLER RC1 Light Sensor Driver Circuit PIR Sensor Figure 3 Block Diagram for a room controller interacting with one LED down panel Driver circuit IIL WHITE LED DOWN PANEL Even with the leaps and bounds that have taken place in power LEDs in recent years a single device is rarely enough to provide all the light needed for general illumination More than one LED will be needed if goal is to light a space formerly occupied by at the light bulb Various white LEDs are arranged in a definite order to form a white LED down panel Placing the LEDs in series guarantees that the same current flows through each device In series combination if any of the LEDs fail and create an open circuit the entire white LED down panel goes dark In addition this configuration leads to highest outpu
14. nels using pulse width modulation technique B Controlling the dimming of lights PWM technique PWM is a modulation technique in which the width of digital pulses of signal is varied according to the amplitude of analog signal 1 Duty cycle is defined as the percentage of the ratio of the ON time to the total time i e ON OFF time in a fixed period of are me Cuty orale m Toil tae Lod PWM technique is a widely used digital technique used for dimming of LED down panels This is accomplished by keeping the LED off for a longer period than it is on Wolts Total Time ee ON Time le 50 Duty cv ib il i Fig 8 waveform of 50 duty cycle 422 Volts Fig 9 Waveform of 25 duty cycle These strobes are for such short times that human eye could not detect them The longer is led is kept on the brighter it appears to the observer For example if the LED is kept off for 80 time the light intensity as observed by the observer will be 20 of its maximum One of the important features of this technique is the wide dimming range offered by it The minimum brightness level that could be achieved is 0 01 times of its maximum level thus offering a ratio of 100 1 dimming ratio 1 STRATEGIES TO IMPLEMENT PWM IN CASE OF LPC2148 ARM7 MICROCONTROLLER USING INBUILT PWN MODULE void PWM void PINSEL1 0x00000400 to select pin PO 2 for PWM5 PWMTCR 0x00000002 resets PWM function of timer PWMPR 0x0
15. put to 5 V De we use a driver circuit which converts the 3 3 V Dc to 5 V Dc by using 2 BJTs in cascaded structure The output pin of the PIR module is connected to the base of the NPN BJT which supplied with 5 V collector supply The emitter output acts a base input for the second PNP BJT Thus the output of the circuit is 5 V which is connected to port 2 of LPC2148 ARM 7 microcontroller LPC2148 PIR Module Figure12 Driver Circuit used with PIR sensor A Strategies to implement PIR code in case of LPC2148 ARM7 microcontroller void main long unsigned int temp IODIRO 0x00000000 configuring port 0 as input IODIR1 Oxffffffff configuring port 1 as output IOCLR1 Oxffffffff temp IOPINO while 1 if temp 0x00000001 delay 500 wait for PIR sensor to respond if temp 0x00000001 IOSET1 0x80000001 LED panel ON else i IOCLR1 0xffffffFf LED panel OFF j else IOCLR1 Oxffffffff LED panel OFF j j j In this way we have implemented the code for detection of human using PIR sensors The registers used are general purpose input output registers of LPC2148 microcontroller 7 VI CONCLUSION Integrating light sensor with PIR sensors to control the dimming of white LED down panels by using PWM technique to a 32 bit microcontroller is achieved Expanding this controlling feature to the whole building will definitely reduce energy wastage The implementation of
16. t voltage which translates into larger more expensive circuit components and more requirements for safety Thus LEDs must be Proc of the Intl Conf on Advances in Electronics Electrical and Computer Science Engineering EEC 2012 arranged in a series parallel array This arrangement has the advantage of using a lower output voltage and reducing the hazard of electric shock If one LED fails open circuit the other two branches continue to operate Fig 4 Square white LED panel of 12V White LED down panel shown in above figure has a 4 6 series parallel array i e it consists of 6 parallel branches with each branch having 4 LEDs in series Voltage across each LED in series combination is 3volts resulting in grand total of 12 volts across each parallel branch of the white LED down panel LED driver being a current source will force current I 6 current I is the current drawn through the LED driver through each parallel branch y Fig 5 Back side of the white LED panel showing series configuration The figure 5 shows the series connection of four White LEDs on a single strip and showing black covering on each series connected LED The black covering on each back side of the LED is the heat sink to avoid LED from large current flow or burning of the connection due to the high voltage A Lux meter reading of white LED panel To calculate the light intensity radiated a single 12 volts white LED panel a dark prototype
17. whose GPIO pin is connected to the base B of the NPN BC547 transistors and the output of this transistor is at collector C connected to the input base B of the PNP BC188 transistor The output of the intermediate circuit is taken at the collector C terminal of the PNP transistor connected to the positive terminal of the white LED down panel The three terminals i e emitter E of the NPN transistor collector C of the PNP transistor and the negative terminal of the white LED down panel in the above figure are connected to ground According to the schematic diagram when LPC2148 microcontroller pin is at high the connection between the emitter and collector terminal of the PNP transistor goes open circuit So the output at collector terminal of the PNP transistor goes low i e O V due to the open circuit of PNP transistor Similarly when the same pin of the microcontroller is at low the connection between the emitter and the collector terminal of the NPN transistor goes closed circuit and the output at the collector terminal is observed high i e 12 V IV INTEGRATING DAYLIGHT WITH ARTIFICIAL LIGHTS As stated earlier one of the strategy to save energy is to integrate the day light with artificial lights to attain an optimal level of luminance in the area This is achieved by using 1 Light sensors for sensing and 2 Exploiting an inbuilt feature PWM of LPC 2148 for dimming of lights A Using Light Sensors for sensing
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