@Camble

thanks for that, i will have a look. Im actually running the tiny (and the pi) direct from the battery, so i technically dont need the analog pin to read the voltage, i found some code a while back that lets the tiny measure its own internal voltage

the biggest issue i have seen with all the posts on this board (other than the price) is the 5 amps power requirements!!!

well i had thought the tiny could have to values to read write to (tiny in slave mode), voltage and status. tiny can read voltage, show the right colour on the neopixel, keep the pi on pi can read the voltage/status once a second maybe. if the status determines it, the pi will shut down, if the pi i...

Hi [mention]camble[/mention] did you make much progress on this? I was thinking of doing something similar, switch/FET/NeoPixel and use it to switch the pi too. i initially thought the attiny could grab the voltage, and time how long ago the last i2c read was, using that 'last read' to decide if the...