I’m working on a project that utilizes a Adafruit Motor Shield driving an encoder enabled 67:1 gearbox dc motor and i’m noticing I’m hearing a lot of high-pitched noise especially at low speeds (which makes sense due to the PWM from the shield to the motor dipping within the audible range). I’m looking for ways to mitigate the noise because ideally my device will be usable in quiet spaces. I’ve read that pwm noise can be filtered off by attaching a 0.1uf cap between the each of the pins of the motor and the casing of the motor. I’ve also considered using a 100 or 300:1 ratio gearbox to make sure the circuit is driving at a higher PWM, though this still doesnt help when the motor is halted. Can anyone provide me some insight with regards to reducing noise in a PID controlled DC motor when it is near to resting or resting. Any thoughts would be greatly appreciated!
Capacitors would be the first approach. If you plan to drive a motor primarily at low speeds, then it’s best to use a motor with a high gear ratio (planetary for high efficiency).