[Jarek] found a non-functional robotic arm sitting around and wanted to get it working again. By adding a few custom boards to an Arduino he managed to do just that.

The arm is driven by six stepper motors, each having four control wires. To handle all of these [Jarek] used TIP120 transistors to protect the controller. This still leaves the problem of 24 control wires to connect. By using a couple of 74HC4514 demultiplex chips he cut that number down to just 8 Arduino control pins. He completed the project by interfacing an original Playstation controller as the input device.

Source code for the project is available for download but we didn’t see a schematic for his setup. This shouldn’t be a problem as the low parts count should mean the datasheets for the transistors and demultiplexers are all you really need.