RM Nimbus - PS/2 Keyboard Conversion

The Nimbus PC-186 used a non standard keyboard protocol.
It used the XT scancode, using inverted TTL at a set baud rate

This combination of factors means that the original RM Nimbus PC can only use the original keyboard.
The later slimline version used a standard PS/2 keyboard.
There tend to be more Nimbus base units than there are keyboards and finding a keyboard seperate to the Nimbus is, in my experience, almost impossible.

Here I have created an interface to the Nimbus that allows a standard PS/2 keyboard to control it.
It uses an Arduino Nano and is powered from the Nimbus keyboard port.

The project uses an Arduino Nano and the HEX file can be downloaded from HERE

Any PS/2 keyboard can then be used with the Nimbus!

The inside of the box is potted to hold all the connections to the socket secure and give it a nice finish.
The Nano is socketed and can be removed for simple replacement or programmed in situe using USB