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the_robo_guy
04-13-2006, 10:29 PM
hey guy

i am making a speed regulator for a 12DV fan, i heard i can do it with PWM,
could you tell me how i can implement this?

or of any other way to regulate the speed of a 12dv fan from a microcontroler?

i am using the 8052,


also has anyone used adc808 is it easy to find in delhi?


thanks
Mohit

docel
04-13-2006, 11:14 PM
1. APLUS INDIA HAS A 20 RUPEE SPEED CONTROLLER FOR FANS.
2. wHY DO YOU WANT OBSOLETE ADCs?
3. For a 12VDC fan, a simple 555 ic circuit will do. You dont need an 8051 for it.
4. Stop using microcontrollers for every simple applications.

ice
04-14-2006, 12:40 AM
Google for "PWM microcontroller",you will have a lot of info.

PWM is a technique where you vary the DC voltage going into your application.
It's advantage is that you dont have to keep the line high all the time,but you do it in the form of rapid pulses.If you average the pulses ,your application gets a DC voltage.This way you save power.

If really wish to use a microcontroller,go for one with a hardware PWM.This way your controller can perform other tasks and the pwm runs in the background.Software PWM is even easier.
In a very simple way ,you just generate a a square wave (the duty cycle will determine the PWM).

Remember,you can do this with a 555 timer and vary the PWM with a potentiometer.

ice
04-14-2006, 12:48 AM
Skipped my mind.
Dont forget to use a motor driver.

yogi
04-14-2006, 02:20 AM
i have provided ckt diagram for this in my book MY EXPERIENCE IN AUTONOMOUS ROBOTICS. Get it from yahoo group-booksbybibin.

It is just a simple ckt consist of one potentiometer. U just vary pot then u will get pwm

the_robo_guy
04-14-2006, 06:51 AM
i am using a controller because it is doing alot more than just regulating the fan.

what chips have hardware pwm? atmega16?

what adc should i use i need 8 chanels?

i will be using a lcd.

ashishvdeshpande
04-14-2006, 08:03 AM
Hi mohit,
Most of the Atmel uc provide H/W PWM channels. Even u can generate interrupt based PWM in 8051 also which will save uc time for other application. Do u want 2 use ADC ATMEGA 16/8515/8535 have 8 ADC channels. Actually these chanels are MULTIPLEXED. If u r using more channels then ADC speed will decrease. And if u hav unused port then yes u can interface LCD. It depend upon ur application how many Port u r using?

deshpande_as
08-09-2006, 08:35 PM
hi all,

I have used PWM to control dc motors successfully.

I just want to ask that, instead of giving pwm pulse direct to the motor coil, how much is it advisable to put a diode or a capacitor or even a low pass filter section? Will it be beneficial?

----------------
regards,
-Amey

sci-3d
10-01-2006, 04:40 PM
This will be useful for you or not? I use 8051 and C Programming generate PWM to control Servos Motor

http://mcu-programming.blogspot.com/2006/09/servo-motor-control.html