Features

The arm is operated by rotating potentiometers to control the motors. To open and close the claw you press a button next to the potentiometers. An Arduino handles the input from the potentiometers and button and drives the servo motors.

Design process

Here’s a simple walkthrough of how I made this arm

1. Sketched design concepts
2. Wrote some geometric proofs and kinematic equations to dimension the arm; plotted kinematics on Matlab to drive dimensions
3. Decided that I’m was ready to tackle this project
4. Ordered metal hardware from eBay and Aliexpress
5. Used the calculated dimensions and started making parts in Solidworks
6. 3D printed the parts and began assembling them with the metal hardware
7. Iterated the design several times until I was somewhat happy
8. Designed electronics schematics
9. Assembled electronics and wired them to arm
10. The arm was ready to play with!