01-04-2011, 11:52 AM
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Power conservation system based on Temperature histogram extraction using Micro-machined Thermopile Array
Introduction
The carbon foot print of individuals and companies is among the biggest concerns world over.
One of the main factors that contribute to the carbon foot print is the power usage.
Reducing the power consumption is a primary motive for all companies, for both environmental and economical reasons.
As of now there is no automated system for power conservation in offices and homes.
This project proposes a solution for the same
Features
The project is based on the controlling the electrical appliances in different sections of a office.
The appliances are controlled based on the presence or absence of individuals in a section of the office.
For detection of human presence, the radiated IR radiations are used.
A thermopile array sensor is used for a accurate and reliable detection.
A autonomous robotic vehicle is used for checking the different areas within a office.
Block Diagram
Hardware Components
PIC 16F877A microcontroller
XBee – Zigbee transceiver
Thermopile array sensor
IC L293 for motor drives
Geared permanent magnet motors
Software Tools
MP Lab IDE for PIC programming
Orcad 16 for schematic design
Eagle layout Editor for PCB design
Labview for virtual instrumentation based control interface on a computer.
Thermopile Sensor
It has an array of very small and very sensitive IR receivers segments.
It is a integrated sensor module, which has a inbuilt ADC and a serial communication interface.
The intensity of the IR signals received by each of the sensor segments is given out as a digital value.
Measures IR radiations in the 2 – 22um range, which is the wave length of radiated by hot bodies.
Microcontroller
PIC16F877A is the microcontroller used in the project.
The controller has peripheral features like inbuilt ADC, required to get the signals from the sensors.
Maximum clock frequency is 20MHz and hence faster than 8051.
Based on RISC and Harvard architecture and hence even more faster.
Embedded C is used for programming the microcontroller.
RS232 Interface
The serial/Comm port of the computer is used for communication with the robot.
The serial port of the computer uses RS232 standard for communication.
RS232 standard voltages are not compatible with conventional TTL / CMOS circuits.
Hence IC MAX232 is used for voltage conversion between RS232 port and the RF Transceiver.
MAX232 enables full duplex communications, while doing the necessary voltage conversions.
H Bridge Motor Drive
The project uses DC motors for robot movement.
DC motors have polarity and direction of rotation depends on direction of current.
Hence for bi-directional motor rotation a H bridge drive is used.
H Bridge drives is a circuit configuration using which direction of current can be changed using control signals.
The project uses IC L293 for implementing H bridge drive.
Each L293 capable of two full H bridges.
Zigbee Transceiver
Used to do communication between the control room module and the robot.
Xbee module is used in the project
Frequency of operation is in the license free ISM band – 2.4GHz
Distance of up to 100mts possible with the XBee module
Is Zigbee compatible
Maximum data rates of up to 250Kbps possible
Uses DSSS and CSMA/CA technologies for reliable communication.
Thank You
