I now have a working programme for the PICAXE which monitors the logic level of GPIO14 (TXD0, physical pin 8) on the Raspberry Pi, amongst other things. Building a test model up on breadboard with a PICAXE 14M2, I included a power-off button (this works alongside the previously mentioned Python script), a reset button, and the control circuit for the relay. And the AA-cell-eating relay! There are of course solid-state relays available, but I’m switching UK mains which is around 240 V rms (should be 230, but it isn’t) and I want it to be OFF off. Completely and absolutely switched the chuff off, with a nice big air-gap between the contacts!
I also like the old-fashioned click of the relay 🙂
Making fun of every situation..!