While working at an institute at my university I used to carry a couple of microcontroller boards in my backpack in case I needed them. I put them in those metal tins you might have seen me use before to protect them from getting damaged. At some point I saw that a half-sized breadboard nicely fits into such a tin with room to spare for a small MCU board so I mocked up some ideas:

Then recently while handling some of the spare PCBs from #Pro Trinket USB Keyboard it struck me that I could just use the MCU part of those boards since I actually designed them to fit into such a tin. And since I have way too many spares I was also looking for ways to use them up. So I soldered one, made some modifications and just put it together like this:

The red and black wires obviously connect Vcc and GND from the MCU to the breadboard with GND being connected on the back like this:

The other black wire on the back of the breadboard connects both GND rails together.

The modifications I mentioned are just a power indicator LED, the typical LED on digital 13 and a button.

I'm not sure if I'll actually use it 'in the field' or if I'll just give it away to a friend but as I mentioned I have a couple of spare PCBs and tins, so if anyone would like to build one contact me :)