Because we only have 4 switches to work with, the two GM9's in the arm are powered by the same

(fixed) power source. With two extensions, this means that if one extension expands fully before the

other one finishes expanding, one motor will reach stall torque and drain the power to maintain stall torque.

To remedy this, we redesigned the first and last teeth on the gear rack to function as a clutch. These clutches

allow the gear to spin freely in one direction and engage with the rack when spinning in the other direction.

With these clutches, we were able to get the motors not to stall, thereby keeping a good speed of extension.

The claw was designed to function like a pin loader at a bowling alley. The main body of the claw is 3D printed

to weigh as little as possible, and two linear sliders move two frames inward to pin droids against a sheet metal frame

in the middle, under the body.We decided to use acrylic frames instead of plates to cut down on weight, and we were

able to cut down the weight by 60%, ending with a final weight of 50 grams or so. The whole thing hangs from the end

of the arm, and to make sure that it's always positioned the same regardless of the angle of the arm, it's held up by a

rotating hinge and what looks like a small clothes hanger. This way, it hangs down freely regardless of the lifting angle.

Raising and lowering a fully extended arm requires a lot of torque, and the mechanism for raising the arm features

a gear ratio of 1:6