Wednesday, July 11, 2007

Monkeyed Around with Utility Arms

Adding to my list of unfinished mini-projects, I started looking into controlling the utility arms through R/C tonight.

The first thing I noticed is that the servo horn I was using was not traveling far enough to pivot the arms completely open. I checked out the settings on the remote, and found that I could affect the start and stop points. Not that it helped much, because I still need to determine where I'm going to secure the servo motors on the frame, and where I'm going to attach the paper clip or other linkage from the servo arms to the utility arms. Matthew Henricks and Mike Senna both have nice setups that I'm studying.

Still, it's a start (just like my unfinished volume controls and plugs for the ankles).


Calvin Thomas said...

I had also planned to attach a servo horn near the pivot point on the arms and then a rod linkage going to the servo. But instead of hooking to the servo direct, I was thinking of using a flat gear rack and a gear on the servo to move the linkage back and fourth. has some of those gear racks on they're site.

Victor Franco said...


I'd be interested in seeing how that ends up working out for you. I'll keep an eye on your blog (as usual).


Anonymous said...

Victor, Calvin.

I also thougth about that and sort of wished i looked at it more. I thought about screwing a plastic gear to the base/pivot of the arm and mounting a gear to the servo. direct drive it. I think there is room and it would work better.

The wire method works well but once i enclosed the back side of the arm area i had issues with the linkage hitting the back wall of the arm pocket. I had to cut open holes that are just too darn big in order to keep the linkage from hitting.

Matthew Henricks said...


That last post was supost to end with


Victor Franco said...

I spent yet more time at Mike's yesterday studying this issue. Mike showed me that the linkage in the arm, along with the paper clip, point straight when the arm is closed, making it harder to pry open.

I will check for clearance before I hook anything up. This is another mini-project I'm trying to close out in the next week or sooner.