PROJECT NAME : Automatic Fan Speed using Temperature (LM35) and PIR sensor.
DESIGNER : Premkumar S/O Selamani.
Block diagram for Project
PROJECT DESCRIPTION:
This project concept can be used for single room where only one person can enter and leave the room. If the person enters the room, the PIR sensor placed beside the door will detect and send signal to microcontroller 8051. PIR sensor signal will ON the fan and operates at automatic speed level selected by microcontroller logic operation based on temperature detected using LM35 temp sensor. 5V DC Relay is used for fan speed switching. LCD display will display the fan speed level and temp value. When the person going out of room, the PIR sensor will detect again and this time the fan will OFF and LCD display will display "FAN OFF".
Schematic diagram for Project
EQUIPMENTS/COMPONENTS USED:
PIR Sensor, Temperature sensor LM35, Analog to Digital Converter 0804, Microcontroller 8051 Project Board, LCD Display Module, 12'' AC table fan, 5V DC SPDT Relay, ULN2803 Relay Driver, few resistors and capacitors.
PROGRAMMING LANGUAGE : 8051 Assembly language
PROGRAMMING METHODS USED:
1. External hardware interrupt function for PIR sensor output monitoring.
2. Analog to digital conversion program to convert analog temp values detected by LM35 to digital for Microcontroller logic operation.
3. Subtraction using compare instruction method for fan speed switching program.
4. Decimal to ASCII conversion to display fan speed level and temp values in LCD display.