hotbed safety

[alaris2 1]

having added my £20 hotbed I admit to being rather pleased with the results-prints are coming out clearer and with nice flat bottoms

but I wonder about safety ?

several of us have had problems with the arduino crashing due to power spikes or whatever what happens if it crashes while controlling a relay-based hotbed?

does a crash automatically open the relay (ie. bed off) or is it not failsafe.in which case the hotbed just keeps getting hotter?!

what precautions have other hotbed users taken?

[Daid 301]

I highly recommend using the latest Marlin and enable the "WATCHDOG" feature, this will reset the chip on a hardware level in case something goes wrong and temperature control crashes. This reset will hang the chip (due to the Arduino bootloader implementation) but it will turn off all heaters. Leaving you in a safe state.

[alaris2 1]

Ahh! that sounds useful Daid- thanks!