articulating arm help

[MrForbes]

I agree with Joe, you can make a little motor live when driving an arm, but you need to be very careful to make sure it's not going to need to do much work to move the arm, and very little at all to hold it still. We did this in 2007 and it worked fine, we used a gas spring to support the weight of the arm itself, so the motor had very little work to do.

This year we're going to try out a window motor or two for the arm. We will again counter the weight of the arm with a springy type thing. We are also going to add some reduction between the motor and arm, both to slow the arm movement (1/4 second for full arm travel is a bit too fast!) and to reduce the load on the motor. And we have a plan for a nifty way to do this but still allow for that clutch thing that Alan was hinting at. The drive has a built in clutching ability, and it's cheap and locally available. And we've used it before for a different application...we know the slipping part works, which is good because we seem to be unable to get limit switches working