turn_degrees(90) is turning more like 78 degrees when turning right
turn_degrees(-90) is off by a similar amount
how do we diagnose and fix this? Is it possible to return the encoder values in some way that would be useful? Or is there something simpler to try?
In the GoPiGo OS, there is a calibration section. You can change the apparent wheel diameter to “tune” the linear movement and you can change the apparent wheel-to-wheel spacing to “tune” rotational movement. I will try to dig up the exact web page that describes this and add to this post.
Update:
@cyclicalobsessive posted a nice screenshot in this topic: Gopigo3 - Where are the calibration parameters?
Thank you for the information!
Ah… I don’t know how to get to the GoPiGo3 desktop. Looks like that’s a Raspian for Robots thing, maybe? All I see is this:
Never mind - I found it. For anyone else who is looking for the same thing, you click the ? icon next to the wi-fi icon in the upper right corner of the main GoPiGo screen.
Rotation issue is now fixed!
I noticed your first screenshot was incomplete and was going to say look for the “?” in the upper right corner (Yeah, not obvious or that well documented) but glad you found it!
Note that if you have a camera installed and enabled, a window will open above the controller buttons allowing you to see what you’re doing.
Makes a great spy bot… 
No, it just helps you aim more accurately if you want to decapitate your robot under a chair or chase the cat. . .
