Create thermostatic fan without a pin

jphilly

Is it possible to create a fake thermostatic fan? I have an arduino reporting temperatures to my Maestro and I want to have that arduino control the fan too. Additionally I want to have a thermostatic fan configured on the Maestro to stall the delayed ATX shutoff without taking up a pin. My fallback idea is to use an unused pin that isn't capable of PWM. Are either of these possible?

dc42

I think that should be possible using RRF3 and conditional GCode.

jphilly

My printer is currently in pieces so I can't test, but I assume the way to do it with the meta commands would be a macro with basically this:

M409 K"sensors.analog[<sensor number>].lastReading"
while result >= <shut-off temp>
    M409 K"sensors.analog[<sensor number>].lastReading"

M81 S1

Is this correct? It would busywait (which probably isn't important). Is there a way to use them to actually influence M81 S1? (so rather than having a macro to do a delayed shutdown just be able to put M81 S1 in the console)