Two servos simultaneous rotation robot arm

hellobazov

Hello!! I build a robot arm, and I have two servos which are connected to one link, in order to increase the moment of the arm. I know that BS2 can send pulses to different servos with the difference of couple ms, but not simultaneously, on the other hand I have my two servos connected to one rigid body, so I have to turn them without any difference.
If the arm with some weight should keep some angle, then technically at each moment only one servo will hold this angle (and all the weight of the arm), and I won nothing, or there is a solution with BS2?
Thank you!

LoopyByteloose

I have an R/C airplane project with two servos that control the wing flaps in the same directional motion. The plans just suggest to construct a cable that shares the same signal for two servos.

In other words, if the motion of these two servos is supposed to be exactly the same in direction and degree, you might be able to take the single output from the BasicStamp and share it with the two.

Will that work for you? This would be simultaneous and I doubt that you would stress the output pin of the BS.

Martin_H

What I've seen people do is mount the servos facing the same direction. This means one servo is between the supports. This allows the same pulse to control both servos which you can do with a spliter cable. In my arm I used a single metal geared high torque servo which produced as much torque as two standard servos.

LoopyByteloose

Thanks Martin_H, I missed that they were going in opposing directions.

hellobazov

Thanks, it solves the problem!

erco

Probably OK. The servos will be somewhat synchronized over their full range of travel, but they may be slightly out of sync at some spots. As long as your arm links aren't perfectly rigid, they can flex a bit to accomodate the angular difference.

Edit: And yes, you can connect both servos to one Stamp I/O pin.