Servo problem on GoPiGo3

servo

#1

Hi Dexter people, my son and I were trying out some of your sample code today for the servo. Using the servo_reset command caused it to swing hard in one direction, it got very hot before we could safely shut the GoPiGo3 down, and then it wouldn’t move after that. We’ve tried fresh batteries and all the diagnostic tools: everything seems fine (as far as we can tell) except the servo no longer moves: it doesn’t even do the little jerky move at startup time. What can I do please?

Thank you.


#2

Hi @andrew2,

The Servo.servo_reset command sets your servo to be centered and it definitely doesn’t swing it to either side.

Did you have anything connected to the servo’s arm that might have stand in its way? Can you show us a photo of your setup when you had it run?

If the servo no longer does anything, then most likely it’s burned.

Thank you!


#3

@andrew2 Have you updated the software for you GoPiGo3 recently?

There was a problem with the servo_reset() function in the easygopigo3 library that was fixed on Nov 2, 2017.

See the following forum thread:
https://forum.dexterindustries.com/t/servo-jams-with-reset-servo/3829


#4

Hi, yes the software was all up to date. After thinking about it a bit more I think it wasn’t the reset command that was the problem, I think it was because we asked Dex to turn his servo to 0 or 180 and because the servo isn’t calibrated to 180 degrees exactly, one of those extremities wasn’t possible for the servo. The servo would have kept trying to push past whatever the physical limit was to try and reach 0 or 180 and then overheated. I bought an SG90 servo as a replacement for only a few dollars. It was really easy to fit and it’s compatible with the original so Dex is up and running again now.


#5

@andrew2

Glad to hear you’ve resolved your problem. Some servos can’t rotate through the full 0°-180° range and can be damaged if you try to exceed the range of your individual servo. As you’ve discovered these small servos are inexpensive and easy to obtain. I still have the original servo that came with my GoPiGo3 attached to my distance sensor and I’ve also bought 4 MG90S servos. I’ve done some experimenting with them and they all have different range limits.

-Kevin