It’s really just an ATTiny85 – a favorite of the crowd that’s just slightly above Arduino level – and ... Four of the six IO pins on the ‘Tiny85 are broken out on a pin header; two ...

I also need to get my ATtiny to go to sleep when not processing anything. And that involves setting pins to ‘interrupt-on-change’ and getting the chip to ‘wake-on-interrupt’ – all stuff I could have ...