I was having a chat with a friend of mine, Tony Davies of DCS Electronics in the UK. We were discussing possible expansions for the ZX Spectrum and arrived at a system of plug in modules for experimentation and utility. I commented that it would be a little like ByteDelight’s Speccy Breadboard but with different features.

Tony and I hashed out the idea and I began designing the board. I based the outline on the successful ZX Diag Cart sold by ByteDelight since I had the original files to hand and lots of people said they had appreciated the two indents on the board allowing easy removal from the rear of the Spectrum.

During our discussions, Tony and I decided that we could forgo the video signals from the rear edge connector and most of the voltages. We reasoned that any small projects or peripherals could use the Spectrum’s internal +5v and anything needing more current could use the raw +9v from the Spectrum’s power supply and regulate to taste.

We christened it ZX Chameleon due to that fact it can change it’s character (or colour) depending on the use it was put to. I retained the NMI and RESET buttons from the Diag Cart since there was enough room and they were already part of the original design.

Having designed the carrier board, it was time to go ahead with some sort of expansion module. I settled on a prototyping board because I’d attempted this once before and been unsuccessful. This board took a long time to lay out and clean up but I think it was worth it. I modelled it on a regular breadboard with added ground lines and voltage connections available.

The board allows for a couple of ICs placed in the center and plenty of space for discreet components. The connections to the Spectrum are easily connected from the rows of connections next to the headers.

It was around this time when I re-read ByteDelight’s product description for their Speccy Breadboard. I was struck by how similar the designs and intent was. Despite having designed the Chameleon from the ground up effectively. Tony and I have since chatted to Ben of ByteDelight and he is happy to sell the Chameleon and expansion boards along with DCS Electronics.

A first run of boards has been ordered and will be duly put through their paces. In the meantime, you can currently pre-order the boards on the DCS Electronics website.

We are hoping that this will be a great platform for experimenting and useful expansions for the Sinclair ZX Spectrum. If you have any ideas for module units, please contact me through the usual channels.