Quiet Motors for Lab Experiments

[eerocketman]

Hi Everyone,

I am currently studying the behavior of mice in a lab. I would like to create a fixture that includes a motor, but I ma worried that the sound from the motor will interfere with the conditioning of the mice. Does anyone have suggestions for small brushed DC motors that are very very quiet. OR would getting a regular motor and creating a sound proof housing be a better solution to this problem?

Thanks!

[cdev]

The quietest computer fans might be good places to start. You could seriously undervolt them if you needed even less noise from them. then use nylon gears - plastic gears to transform the force to whatever you needed quietly.

[_Wim_]

Hi Everyone,

I am currently studying the behavior of mice in a lab. I would like to create a fixture that includes a motor, but I ma worried that the sound from the motor will interfere with the conditioning of the mice. Does anyone have suggestions for small brushed DC motors that are very very quiet. OR would getting a regular motor and creating a sound proof housing be a better solution to this problem?

Thanks!

What torque and rpm you need. For high quality motors and professional projects Maxon Motors is one of the best and plenty of choice. There DC motor running at low RPM (motors without a gear box that is) are very quiet.

As suggested above, if high torque is needed and thus a gearbox, go for nylon gears instead of metal gearing, but I think a better approach is to oversize the motor and run at low rpm

[Alex Eisenhut]

To do what? Wax motors for simple actions are good.

[ChrisLX200]

Mice soon get used to continuous low-level background noise, so run the motor (or play a looped soundtrack of it) continuously then they will ignore it.

[beanflying]

These are great but $$$$  https://www.maxonmotor.com/maxon/view/content/products

[Terry01]

Brushless motors are more economical and quieter too. Both by quite a bit. The Internet is awash! You should get something for very little £££s. Remember everything you need will be tiny size!

Good luck! 

[nidlaX]

Mice soon get used to continuous low-level background noise, so run the motor (or play a looped soundtrack of it) continuously then they will ignore it.

Definitely consider doing this. Mice apparently can hear between 1kHz to 70kHz (https://en.wikipedia.org/wiki/Hearing_range#Mice), so you may want to profile the environmental noise of the entire setup before you begin your experiment. You might also consider some degree of sound isolation between the motor and the mice's enclosure using some transfer gearing or pulleys.

[jmelson]

These are great but $$$$  https://www.maxonmotor.com/maxon/view/content/products

I second this, Maxon motors can be extremely quiet if run at relatively low speeds.

Jon

[eKretz]

Some other very high quality motor brands (very quiet running) in addition to Maxon are Faulhaber, Bühler, and Portescap. Be forewarned, none of them are budget priced. Abundantly available secondhand on eBay and some surplus sites for good prices though.

[CM800]

Mice soon get used to continuous low-level background noise, so run the motor (or play a looped soundtrack of it) continuously then they will ignore it.

Definitely consider doing this. Mice apparently can hear between 1kHz to 70kHz (https://en.wikipedia.org/wiki/Hearing_range#Mice), so you may want to profile the environmental noise of the entire setup before you begin your experiment. You might also consider some degree of sound isolation between the motor and the mice's enclosure using some transfer gearing or pulleys.

That could be a concern indeed considering most drives operate at 20kHz PWM.

They could well hear all the tuning loops etc.

If you wanted absolute certainty of silence (beyond testing the whole noise range)
I'd look at using some kind of "hydraulic motor" or pnumatic motor which will have no PWM sounds, you can then drive that from a distance with a small power-pack.

If you can't find a Hydraulic motor, I'd look at 3d printing something. There's probibly something suitable somewhere.

Honestly Overkill (small plastic 3D Printed part would do you better if it's low power)

http://www.surpluscenter.com/Hydraulics/Hydraulic-Motors/Low-Speed-High-Torque-Hydraulic-Motors/?page_no=1&sort_by_options=price+asc


Bit of a novel solution. 

[ChrisLX200]

I was in the animal behavoural science area for more years than I care to remember, and I can tell you that you will need to acclimatize them to the test environment over a period of days. If you don't then subtle traits will be swamped by exploratory behaviour. Even someone new walking into the room (who smells different) will trigger intense interest from the animals. We used to use sound-proofed rooms together with a backround sound level sufficient to mask normal lab activities within. The room also had offset day/night lighting cycle because the critters tend to sleep most of the day and are active at night. There are far too many other considerations to provide advice here, just know that if you expect to get valid data that a peer review won't destroy you need to take the test environment very seriously.

edit: The actual noise level - provided it is not excessive - is irrelevant. Mice/rats will consider any new noise they are not acclimated to as a threat until proven otherwise. It's that which you need to control and which takes the time.

[eerocketman]

The issue is that this is an auditory experiment where the motor is only active when there is a specific sound that we want the mice to react to. The test environment itself is completely sound proof with its own day night cycle.

[Mr. Scram]

The issue is that this is an auditory experiment where the motor is only active when there is a specific sound that we want the mice to react to. The test environment itself is completely sound proof with its own day night cycle.

I'd say you risk influencing your experiment even with the quietest motor. You never get them entirely without sound and vibrations. It's probably a good idea to design the experiment in such a way that the motor sound can be excluded from the results.

[Zero999]

Mice soon get used to continuous low-level background noise, so run the motor (or play a looped soundtrack of it) continuously then they will ignore it.

Definitely consider doing this. Mice apparently can hear between 1kHz to 70kHz (https://en.wikipedia.org/wiki/Hearing_range#Mice), so you may want to profile the environmental noise of the entire setup before you begin your experiment. You might also consider some degree of sound isolation between the motor and the mice's enclosure using some transfer gearing or pulleys.

This suggests up to 110kHz.
https://en.wikipedia.org/wiki/House_mouse#Life_cycle_and_reproduction

Avoid PWM.

Mouse's hearing is less sensitive than humans' at lower frequencies, <1kHz, so even if you can hear it, that may not be  a problem. Perhaps it might be better to use mains frequency motors? The lower voltage type, designed to be run off a transformer. If a variable speed is required, it could be driven with an audio amplifier (class AB, not class D!) and a suitable sine wave signal, though plenty of filtering would be needed if it's digitally generated.

Have you considered smell? Mouse have a very sensitive smell, much better than humans. The lubricant used in the gear system and many plastics emit odours, which could be off-putting to mice.

[BrianHG]

Look for DC motors designed for 0 cogging, fat wide diameter bodies, balanced, and run the at low RPM.  You may add a heavy flywheel to further lower noise.

Your drive power supply should be linear if you are worried about high frequency noise coming from a PWM drive.

For low rpm and low strength, you may also look at 3 phase or multi-phase brush-less motors fed with low power fundamental square wave or sine wave.  Something similar to what you would find in old 3.5inch floppy drive motors.  Slow regulated speed and silent, well the better ones were silent...

[xani]

Mice soon get used to continuous low-level background noise, so run the motor (or play a looped soundtrack of it) continuously then they will ignore it.

Definitely consider doing this. Mice apparently can hear between 1kHz to 70kHz (https://en.wikipedia.org/wiki/Hearing_range#Mice), so you may want to profile the environmental noise of the entire setup before you begin your experiment. You might also consider some degree of sound isolation between the motor and the mice's enclosure using some transfer gearing or pulleys.

Huh, didn't know it goes that high, I wonder if they can hear some DC converters then

[Zero999]

Look for DC motors designed for 0 cogging, fat wide diameter bodies, balanced, and run the at low RPM.  You may add a heavy flywheel to further lower noise.

Your drive power supply should be linear if you are worried about high frequency noise coming from a PWM drive.

For low rpm and low strength, you may also look at 3 phase or multi-phase brush-less motors fed with low power fundamental square wave or sine wave.  Something similar to what you would find in old 3.5inch floppy drive motors.  Slow regulated speed and silent, well the better ones were silent...

Good idea, but beware of square waves, which can cause buzzing, at the harmonic frequencies, even if the fundamental is inaudible to the mouse.

[m98]

What are you trying to accomplish with that motor?

[beanflying]

The maxxon motors don't cog (rotor design), have no brushes and linear speed control is the way to go to avoid the frequency issue. Not to mention generally around 80-90%+ efficient so little heat generated.

Brushless BDLC speed controllers are very noisy in particular and chopper dc circuits the same.