So once i got the keyboard working, i had a little play with the attiny85. My basic code would use some internal reference trickery to get the internal voltage, then reporting back over i2c. The problem being, an attiny85 doesnt actually have proper i2c support, and so it was flakey to say the least!!

So after some searching, I found that the attiny88 has better i2c support, and more pins too, meaning that i can use a proper interrupt for the on/off button too. as a third and final bonus, it is also a few pence cheaper!!! it pays to look around eh!!

Some other changes see the power button being swapped for a 90 degree one to sit top centre on the board, and the neopixel has been moved to the back to save the eyes. It will work better too, filling the area between the pcb and the pi, with a glow of light. or maybe it could be used to illuminate a power switch later

there was of course a few fixes to the original design to correct my wildly inaccurate guesses on the keyboard chip, simply adding some more pullups, and i think we are good to go....

how many times can i check before i press the go button?