Let's see if you can help me... (Motors)

[Idaman323]

Ok, out robot uses two pivot points in the arm. One is at the top of the supports... the arm goes down and another near the ground that goes back up. Understand?... Kinda like a shoulder/elbow arm.

We have two window motors mounted halfway up the supports that have a smaller sprocket that run up to the arm with a bigger sprocket. I think its a 4 to 1 ratio.

The arm raises fine and stays up fine with no problems. The problem comes in when we want to drop the arm down. Right when you start dropping the arm it will not stop. It just keeps dropping all the way until it hits the floor. Then we have to raise it up and repeat the process when we want to go down again. This gives us very little control.

Any help on how we can fix this problem?

-Thanks,
Justin