I'm hopefully going to put together a picaxe based 'alarm', which will sound when/if I leave the power switched on at the wall when I've turned the PC off. Leaving it like this wastes electricity, as the monitor etc are still on standby, and I keep forgetting...
Powered from a 5V phone charger, it will take input from the 5V line of the PC's PSU, and activate a piezo buzzer glued to the bottom of a small tin) if the 5V signal is not present. So, if the picaxe is powered up, but the PC is off, the alarm goes, until I switch everything off at the wall.
I think isolating the picaxe input from the PC would be sensible?
Can anyone recommend any particular optocoupler for this? Or would a 10K resistor be adequate?
Powered from a 5V phone charger, it will take input from the 5V line of the PC's PSU, and activate a piezo buzzer glued to the bottom of a small tin) if the 5V signal is not present. So, if the picaxe is powered up, but the PC is off, the alarm goes, until I switch everything off at the wall.
I think isolating the picaxe input from the PC would be sensible?
Can anyone recommend any particular optocoupler for this? Or would a 10K resistor be adequate?