i WANT TO DEVELOP A MICROCONTROLLER BASED PID TEMPERATURE CONTROLLER.THE USER WILL SET THE DESIRED TEMPERATURE THROUGH KEYBOARD.I WILL BE USING A TEMPERATURE SENSOR(IC LM35DZ) WHICH WILL BE INPUT TO MICROCONTROLLER 8051 WHICH WILL IMPLEMENT PID ALGORITHM TO CONTROL A RELAY AND HENCE EITHER TURN ON A HEATER OR A COOLER.AN LCD WILL ALSO BE INTERFACED TO DIPLAY THE SET TEMPERATURE AND ACTUAL TEMPERATURE. I DO NOT KNOW THE C CODE FOR THIS.IF ANYONE HAS WORKED ON SUCH KIND OF SYSTEM ,THEN PLEASE SEND ME THE CODE.I WILL BE REALLY VERY GREATFUL