The micro cannot avoid hooking up to the real world which full of electrical noise, isn't it ?

Can somebody provide a low cost really clean power supply solution ?

I am using 2051 with a triac coupled with 3021 opto.
It drives a motor. I have to vary the speed of the motor, thus using an LDR in series to output of 3021. (ldr is face to face with led that gives different brightness for different resistance of ldr, or for diffrenet speeds of motor in other words).

Most of the time, while changing the speed of the motor, the micro resets :(

I think its the noise that motor generates while changing the trigerring time thru ldr.

Shall I use snubber at the triac or the snubber at the power supply of the micro .

Rauf, I think you have made such an application of controlling fan speed.
How did you kill the noise problem.

Thank you.

Babar/