I am doing an animatronics project and as you might have guessed, the high pitch stretching noise that is coming out of servos is not welcome. Actually it can ruin the whole project.
Now, I googled around and the only solution that hasn't been mentioned was this one: how about filling up the gearbox with some sort of non-conductive gel, which would in turn muff the noise?
Can anybody think of a some kind of gel that would be a good candidate for this task.
I take ti wrapping them in sound insulation foam isn't an option. So i'm guessing the servos have to stay out in the open and are visible?
Wrapping them up into some sound proof insulation is an obvious solution.
But yes, there is not much space and there is almost no shell to suppress the sound. They will be almost visible from the outside.
Bigger problem is that one would need about 10 of them, lined up in pairs, every 10". They would all work at once, so there would be lots of noise to suppress.
No sure filling them with a liquid, even no conductive, will be a good idea. But you can give mineral oil a try. Its often used in fish tank PCs. Where the PC is fully submerged in the liquid. Good for aesthetics and cooling. Keep in mind that any fluid you add to it will likely slow the servos down.
Do the servos have to all be in the same spot? Can you put the servos in a remote (soundproofed) box, and run cable push/pull assemblies to the points that need motion?
a thick grease could work, it might also stay in place a bit better,
looks like this'll require some trial and error
it is kind of a music tree. Like a bamboos, 2-3m (6-9ft) tall with two axes hinges every 50cm (20"). When you come close to the tree it wakes up and plays music back to you. It has US or IR sensors, in each stem, so it can read your body movements and dance with you or if you brings your hands close to it you can 'sculpt' it into any shape you want.
Now, the whole purpose is to play music and to simulate something that is 'organic'. Screeching servo noise would totally ruin the whole thing.
I think a thick grease sounds good. Which grease would be non-conductive?
I would give Lithium grease a try. This is thin grease and only a thin layer is needed. It has excellent lubrication properties and will likely reduce inertia rather than add to it. Also it will stick and stay in contrast to oil which will quickly wash away. I would apply the grease to servo gears and anything (joints, attachments) than can cause friction in your design.
Not sure it will help you, but here it goes...
I was faced with exactly the same problem using servos in a video conferencing terminal (pan / tilt).
I sort of solved the problem by stepping the servos in little increments rather than jerk them in large increments. This reduced the whine bursts considerably, but also slows down the motion - which was no problem in our application.
I also suspended control pulses when no motion was required (relying on friction to keep the servo position) - this keeps the servos quiet in idle state.
ALternatively, place servos away from the project, use bowden cables to transfer the motion. (any RC hobbyshop has the stuff you need)
Success!
it is kind of a music tree. Like a bamboos, 2-3m (6-9ft) tall with two axes hinges every 50cm (20"). When you come close to the tree it wakes up and plays music back to you. It has US or IR sensors, in each stem, so it can read your body movements and dance with you or if you brings your hands close to it you can 'sculpt' it into any shape you want.
It actually sounds like using push/pull cabling, then hiding the servos in a sound-proofed box (ie, the "planter" potting?) would be your best bet, provided you could stuff enough of the cables in the "trunk" of the "tree". The problem would be finding small enough cables (thin cables and jackets); stuff like bicycle brake cables or such might not be thin enough...