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Robonz wrote:Now I think about it, I did have some noise issues that I solved really simply. I added a 1000uf capacitor directly across my motor. You can see the write up here. It also adds speed stabiliy too. See this
https://www.taswegian.com/NBTV/forum/viewtopic.php?f=35&t=2465
And you can see how solid my sync pulse is here
https://www.taswegian.com/NBTV/forum/viewtopic.php?f=35&t=2447&start=15#p22589
Cheers
Keith
smeezekitty wrote:I can confirm that putting a beefy capacitor across the motor helps a lot. I was suffering from MCU resets, load PWM whine and instability. Putting a 4700uF cap across the motor fixed it up. You don't want the response time too be too quick. It is only being adjusted 12.5 times per second anyway and reacting too fast will tend to cause the loop to oscillate.
I am having a hard time justifying PID because I have a certain range that the motor can stay in to control the speed above or below the desired rpm. The range is very tiny. With a cap, it might take away the need for PID at all. But then, I am not chasing the video sync pulse either.
FlyMario wrote:Am I supposed to put this Electrolytic Capacitor onto the + and - poles of the motor? I did that and my motor sped up incredibly. My PWM went from 204 (normal) to 20 and I could never get down in speed. I put a 1000uf 35v Cap. I also started having trouble with my ATMEGA328 chip. Still puzzled by that as the motor is connected through a MOSFET and nothing I do to the motor should have affected the MCU.
Any ideas?
Pete
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