This is a product build out of necessity, we needed one to build our own kits, like the Cylon and TinyCylon. That being the case we've had a fair few iterations, the first just programmed ATTiny85s and we used that for programming the DIP and SMD versions, just by holding them down on the pads. The second we started thinking about other chips so we could prototype the Cylon and also Barebones and Shrimp Kits. That also contained a crystal and some capacitors. However looking at Adafruit's shield (bottom left) we noticed they didn't use an oscillator, but their code used a pin on PWM to emulate one!
That's when we started to look at our own shield, putting together the first PCB. We got them make at Seeed which meant we had a few spare and offered them to our community. They were snapped up at £5 and one forum member really helped us out with the niggles on the board and suggested some edits. A revised board went off to Ragworm for some UK PCB Prototyping. We tested this version in house to destruction! Happy with this design after three month's use we pulled the trigger and sent them off for a small production run.
Let us know what you think! We have them here for your delectation!