This video shows me testing the top motor driver circuits. In the 1st part of the video, all 5 motors are driven the same. In the 2nd and 3rd part, every 500ms the next motor's direction is changed, stepping through the 5 motors in sequence.
I have designed and built a new CPU after the original was damaged by the backup battery. This new CPU uses an ATMega328 MCU (As in Arduino Uno) to control the motors.
The PCB At the top simply hold the bus transceivers and motor drivers along with power regulators and fuses. The CPU board also has bus transceivers for the two motors below (not connected yet) and also has hardware counters for a new control panel. The CPU board also contains three 3-to-8 decoders to address each transceiver or counter as required.
With the addition of a USB UART, the CPU can talk direct to a PC or other serial data device. Once the software is complete I hope to be able to send basic commands to move the arm.
Currently no limit switches are wired in (but the circuitry is there). The software is only basic at the moment, with the transceiver and counter addressing complete but no input function written.