Let's Make Robots!

How to reduce servo noise?

So it has come to my attention that like motors, servos too need capacitors over the power and signal lines. Well my question is exactly what value capacitor and on what servo pin. I looked online and could not exactly find it, maybe you have a link. I dont know if it is specific to what servo you have but here is the link to mine http://www.hobbypartz.com/topromisesg9.html

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Don't forget to search for "jitter" as well.
i wouldnt call what is going on with my servo "jitter" it is completely moving around in wrong directions when told to do nothing. It moves a bit too when i turn the power on.
might be similar nevertheless!
so would this circuit, well the .1uf capacitors, be the fix? http://letsmakerobots.com/node/5222#comment-17107

Those caps are intended to suppress the noise at the source of the noise. In that case the solenoid. I do not know what the source of your noise is. So I cannot begin to think what kind of caps you need and where to put them.

It might be possible to suppress the noise at the servo that is disturbed by the noise. But I doubt it will be very effective.

The best bet is always to find the source. Maybe you can eliminate noisy candidates by removing them temporarily from your project. Or replacing them by less noisy alternatives. For example, use batteries instead of a transformer. Remove the Sharp IR distance sensor all together. Strip down your complex robot to the bare MCU/Servo/power combo and prove that that combo works well.

Then start building it up again. Step by step. When the servo start to misbehave again you'll know the latest addition was the culprit. Then burn it, smash it, crush it or use it for a different project. And tell us about it.

Give this a try:


Place C1 as close to the incoming power lines as posible. Place a copy of C2 and C3 as close to the servo cable socket as possible for each servo.

Perfecto ;)

I am having a similar issue but the resistors did not seem to help.

at controller idle the servo moves back and forth about 10 or 15 deg.

any idea?


Just curious...

By resistors did you mean Capacitors? It's not going to work the same if you're using resistors where capacitors should be. :)

i got same issue now.

the problem is not due to noise on servo power rail

100 pF cap on the servo signal pin is enought to solve the problem...