Rhino XR-2 Robotic Arm

About
The XR-2 is a 4 (5? One motor not terminated) Degree of Freedom Robotic Arm from Rhino Robotics (also known as Sandhu Machine Design?) designed for educational purposes.

Documentation for the model we have (XR-2, Mark 2(?) Controller) is poor.

it uses 12V gear motors with optical encoders to track motor movement, and microswitches as limit switches.

The motor controller has a DB25 RS232 port for interfacing. The serial settings, taken from the Mark III controller are "RS232 Serial Comm Port uses ASCII code at 9600 baud, 7 data bits, 2 stop bits, even parity."

Inside the motor controller case, on the right side, there is a toggle switch labeled "RX" and "TX" wired to the DB25 RS232 port.

Currently there is a raspberry pi mounted to the enclosure running raspbian. Boots to command line or gui. It includes an xbox360 controller driver and several python scripts with fun names like "joystick.py".

An xbox360 controller would make troubleshooting easier.

Power indicator lights on the main control unit are not functioning, although robot arm seems to get power when plugged in.

USB jack on raspberry pi is damaged. one of two ports functions. This means one cannot plug in an input device and output to robot arm at the same time. Replacement parts have been ordered via slow boat. (EMW, 10/1/15).

Relevant Links
Manufacturer Page

IEEE Whitepaper On Firmware, Contains Serial Command Set

IEEE Whitepaper On Motor Controller, Contains Encoder and Other Schematics

Matlab Code to Control Arm with Xbox 360 Controller