Silent servo

I am looking to make an instrument (harp) where strings are plucked to make noise. Some of the strings I want to pluck with a servo, have you any recommendations for a servo that is silent or at least quite. It doesn't have to be very powerful. Thanks.

I googled around some old R/C sites and didn't find anything promising. Only specific opinion was from someone that sounded as old as you and I are. ;)

The servos we use in our planes are notoriously noisy. The digitals can be less noisy, but they also have a "whine", part of the digital technology, and it can be aggravating, as well. And, the faster they are moving, the more torque they are generating, thus, more noise. You are right, the mounting can help quite a bit. You can also cut a foam block, that can fit around it, and that will help quiet them down a bit. All the servos have a 3 or 4 gear train, and that's where the noise comes from, plus, add the whine from the digital circuitry, and the digitals can be louder over all. Most of the cheaper ones have nylon gears, and the more expensive ones are metal.

The big thing is, the servos are used for moving flight surfaces in flight, where the noise doesn't matter, so there are no requirements to be quiet. So, NO one makes a "quiet" servo. Other than padding and mounting, or going through a bunch of servos, there's no way to get a quiet one.

I have actually saved a plane stuck in the trees, because of the noise - we lost it, had NO idea where it had come down, but by working the control surfaces, we finally heard the servos, and found the plane...

Been flying RC planes for 25 years...ain't heard a "quiet" one yet! Again, you can pad it quite well, and there's really no need to worry about heat build-up - the case is sealed anyway, so there's not much need for heat dissipation.

Good luck!


You might try placing the servos in a padded, soundproofed box, and leading the actuators out to where they're mounted using flexible shafting (rotation) or tubing with flexible push/pull (linear motion) wire in it.

Its too bad they don't make small servos with helical gearing; that would cut down on noise quite a bit...but as lefty's already posted, there isn't really a need for quiet servos for the market they're sold in.


From ebay:

Stainless Steel 10mm Bore 15mm Stroke Single Rod Pneumatic Air Cylinder


I'll believe those pneumatic servos won't make that whining noise. But what about the noise they do make, you don't want that while listening to delicate harp play.

How about filling a servo with grease (oil would be hard to keep inside), would that help ?

Thanks, but this thread is over three years old. I eventually used CD drives to make the actuator. They make some noise but it is somehow fitting. This is a video of the project when I only had 5 strings going.

How many CD drives are on it now?!

I would have though solenoids would be a better choice, adding rubber pads as necessary to suppress any metal-metal clicks.

How many CD drives are on it now?!


I would have though solenoids would be a better choice,

Well project done, it might appear in a book sometime, if a certain publisher gets their finger out.

Hi , could you use a stepper motor to rotate a plucking arm, each rotation the arm strikes past the string, then stops, waiting for the next pluck instruction. I'm sure I've seen somewhere an ancient guitar type instrument that had a winding handle on the end, you rotated the handle to pluck the strings and moved hand up and down the neck like a regular guitar.

Tom.... :)