In my project, I am using a 775 DC Brushed Motor. While I am driving the motor via PWM using Arduino UNO, I am able to hear a buzzing noise that needs to be avoided. One of my clients said adjusting the PWM frequency can solve this issue, so is it related to PWM frequency? If so, what is the optimum frequency range and how can I set it in the Arduino UNO? I found that there are 2 hardware frequencies in Arduino UNO via this random article DC Motor speed controlling using MOSFET, but I am not sure how to adjust it. One main thing I would like to say is that I am controlling six 775 motors, so how do I adjust the PWM of six pins?
Generally, the lowest frequency that moves it outside the audible range is fine. Make sure that your H-Bridge still works at this frequency: I've come across chips that top out around 10kHz.
For 6 PWM outputs, I don't think you'll find anything that will work on an Uno: you need a chip with more hardware timers. Here's an article on changing the Uno PWM frequency: https://docs.arduino.cc/tutorials/generic/secrets-of-arduino-pwm/
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Great, that really makes sense. I am thinking about checking out multiple MCUs, but I took this as a challenge and am still searching for solutions. Anyhow, thanks for suggesting the 10kHz.
HI, @sanjaykumar-tiruppur
Welcome to the forum.
Have you tried more than one of the PWM pins of the UNO, they are not all the same frequency.
Tom... 
yeh i know that. it was mentioned in this Article i said before. But i am unaware of Modifying the PWM Frequency of 6 pin Simultaneously.
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