17-02-2011, 02:12 PM
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AUTOMATIC SPEED CONTROLLERS FOR FANS AND COOLERS
OBJECTIVE:
Aim of this project is to control the Fan/Cooler speed using LM35 temperature measurement.
From the sensor reading the controller find out in which speed it has to run the cooling fan. Then using duty cycle variation method it controls the MOSFET to drive fan in the specific speed.
The LM35 series are precision integrated-circuit temperature sensors, whose output voltage is linearly proportional to the Celsius (Centigrade) temperature. The LM35 thus has an advantage over linear temperature sensors calibrated in ° Kelvin, as the user is not required to subtract a large constant voltage from its output to obtain convenient Centigrade scaling. The LM35 does not require any external calibration or trimming to provide typical accuracies of ±¼°C at room temperature and ±¾°C over a full -55 to +150°C temperature range. Low cost is assured by trimming and calibration at the wafer level. The LM35's low output impedance, linear output, and precise inherent calibration make interfacing to readout or control circuitry especially easy. It can be used with single power supplies, or with plus and minus supplies. As it draws only 60 µA from its supply, it has very low self-heating, less than 0.1°C in still air. The LM35 is rated to operate over a -55° to +150°C temperature range
This project is implemented using PIC micro-controller, driver unit for control the DC fan and LM35.
FIRMWARE DEVELOPMENT TOOLS:
1. Development tool - Mplab
2. Compiler - HI-Tech PIC C
3. Programmer - PIC Flash
APPLICATIONS:
1. Power station
2. Sugar factory
3. Power plant
4. Stabilizer
AUTOMATIC SPEED CONTROLLERS FOR FANS AND COOLERS
OBJECTIVE:
Aim of this project is to control the Fan/Cooler speed using LM35 temperature measurement.
From the sensor reading the controller find out in which speed it has to run the cooling fan. Then using duty cycle variation method it controls the MOSFET to drive fan in the specific speed.
The LM35 series are precision integrated-circuit temperature sensors, whose output voltage is linearly proportional to the Celsius (Centigrade) temperature. The LM35 thus has an advantage over linear temperature sensors calibrated in ° Kelvin, as the user is not required to subtract a large constant voltage from its output to obtain convenient Centigrade scaling. The LM35 does not require any external calibration or trimming to provide typical accuracies of ±¼°C at room temperature and ±¾°C over a full -55 to +150°C temperature range. Low cost is assured by trimming and calibration at the wafer level. The LM35's low output impedance, linear output, and precise inherent calibration make interfacing to readout or control circuitry especially easy. It can be used with single power supplies, or with plus and minus supplies. As it draws only 60 µA from its supply, it has very low self-heating, less than 0.1°C in still air. The LM35 is rated to operate over a -55° to +150°C temperature range
This project is implemented using PIC micro-controller, driver unit for control the DC fan and LM35.
FIRMWARE DEVELOPMENT TOOLS:
1. Development tool - Mplab
2. Compiler - HI-Tech PIC C
3. Programmer - PIC Flash
APPLICATIONS:
1. Power station
2. Sugar factory
3. Power plant
4. Stabilizer
