Motor Speed Control using PIC16F84A (PWM)

[XIST]

Hi Every One!

Can any one help me in Motor Speed Control. Is it there any best way of Controlling motor speed rather than PWM. I want to control the speed of a DC motor Digitally; means through push buttons. I want to that When i push the button the speed of motor should increase until i leave the button...Other wise it should be at constant speed...and also it decreases with a second button in the same fashion...

Waiting for ur kind Suggestions!! Thank You!!

 

[blueroomelectronics]

What's wrong with PWM?

PS get rid of the ancient 16F84A, the 16F88 or 16F628A both have HW PWM and are cheaper too.

 

[XIST]

Thanks for the suggestions bro...
But i have written a code for PWM in C. Then i Attached MOSFET IRF840 with PIC16F84 PWm output pin...Motor starts working but it stops automatically after some time. when i touch the MOSFET by finger at its heat sink place then it starts motor. after some time again motor stop.this process is repeating...Kindly suggest me the best way of operating motor from PWM with PIC. Thanks

 

[blueroomelectronics]

Post your schematic.

 

[mneary]

Your IRF840 has an intermittent solder connection.

 

[smanches]

How about this speculation.

He's running the mosfet high-side but without a proper bootstrap. When he touches the tab, his body capacitance drains the source and allows the bootstrap to recharge again.

Now we just have to find out exactly how/what he is doing.