I built an incubator a while ago https://www.youtube.com/watch?v=CjXmUjoWvG4 and i already used it for several times successfully but i have an issue with it.
This is the scheme: http://i.imgur.com/y5W3Moj.jpg
Occasionally the processor resets or even freezes (happened a few times even tho i activated the watchdog that works, i checked it) when the 12V linear actuator is activated, it can happen on the activation, in the middle or at the termination.
The 5V for the processor and the 5V for the relays and the 12V for the actuator coming from a CPU Power supply from different power cables although i guess that they are connected together inside.
So to eliminate the probability that the current spikes may cause the problem i connected the actuator to external 12V supply and even the relays to 5V external supply but it didn't solved the problem.
I disconnected the actuator's power supply and only activated the relays to see if there any problem with them but as i thought everything worked fine.
Maybe there is an issue with the EMF from the relays when the actuator activated (the processor and the relays are few cm apart), but it's beyond my knowledge.
I would be glad to get some help,
Thank you very much.