Society of Robots - Robot Forum

Mechanics and Construction => Mechanics and Construction => Topic started by: Orrin on October 06, 2008, 08:13:22 PM

Title: Servo Issue?
Post by: Orrin on October 06, 2008, 08:13:22 PM
I have successfully built and uploaded my program to the 50$ robot microcontroller. I have verified the program, but it still doesn't work correctly. The servos only spin in one direction.

At first I thought that the photo resistors were damaged, so I replaced and re-soldered them. This did nothing to help. The only thing that happens when I put on power to the board and servos is a continuous rotation. There is no reversal in direction nor any response at all to light or dark.

Now I think it could be my servos. I had them modified by Servocity.com to rotate continuously, instead of doing it myself (I'm lazy  :P). They have a little switch on the outside that reverses direction. Could this have something to do with it? Is there a different pulse signal for this to work?

Thanks,
Orrin  ;D

EDIT: The servos also rotate quite slowly.
Title: Re: Servo Issue?
Post by: ArcMan on October 06, 2008, 08:23:06 PM
(I'm lazy  :P).

Perhaps, but you're going to have to do some good old-fashioned troubleshooting.  Look at the micro's code.  What makes the wheels go forward?  Is that input present?

Welcome to what is about 25% of the time spent on the robotics hobby (at least for me).  Why doesn't this thing do what I want it to?
Title: Re: Servo Issue?
Post by: Admin on October 10, 2008, 04:57:07 AM
Check everything with a multimeter for anything that shouldn't be happening.

If you change the servo speeds in the software, do the servos change speed?
Title: Re: Servo Issue?
Post by: Orrin on October 11, 2008, 09:24:06 PM
I haven't had a chance yet, but the servos don't seem to change speed with the light change. I might end up just making one servo turn and the other one just stay still. It might be slower, but it will still work. I will experiment with different values and see what results.

Thanks for your responses!
Title: Re: Servo Issue?
Post by: sdavis6736 on November 08, 2008, 05:57:15 PM
Do you have common ground to all components, motors and board?  If not, you will have many strange things happening including the servo spinning in one direction, no control.