PWM causing servo to Buzz !

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1

Hi everyone,

I haven’t posted here before so forgive me if this is misplaced!

I am running Angstrom on my SD card and I am trying to get my servo to operate by following this tutorial = http://learn.adafruit.com/controlling-a-servo-with-a-beaglebone-black/overview
The problem is when I follow the tutorial EXACTLY as it is written my servo just buzzes in an extreme position.

I don’t know where to start on this issue so if anyone can point me in the right direction it would be fantastic.

Thanks a lot,
Adrian.

2

Can you put a scope on the PWM line and see what it looks like? It’s got to be either the frequency or the duty cycle, a scope would tell you which.

3

Thanks for getting back Eric, I do not have a scope I’m afraid. I’m running it from my SD card on the latest demo image from Angstrom.

I had originally tried this when I first got my BBB. The image on the emmc at this stage was a bit old compared to the one I am running now. I wonder if something has changed in the Kernel that might cause this …

4

Updating is always a good idea to try first. But I’d be surprised if that fixed this problem. I’m sorry I don’t have any experience with these servos, you should try your question on the Adafruit forums (if you haven’t already). Someone there may have run into the same symptom.