I've finished my first IoT project based on Arduino Yun. It's a remote control for my sauna. Everything is working as expected in test mode (relay is not connected to contactor so there is no real load), I was able to test this system for hours without any problems.
When I hook up contactor to relay, it turns the heater on and off, and everything seems to be working, but after a while (absolutely random, it could be an hour or a few minutes) LCD screen freezes, or sometimes, starts flashing random symbols, server is not responding to commands, rotary encoder isn't working and it seems Arduino freezes. The only workaround is to turn off the power and reset the system. After it restarts, everything is back to normal.
I came across this post 16*2 LCD getting weird characters symptoms are the same, I think high AC load is causing EMF impulse that is crashing Arduino. Power Module, Relay board, LCD, and Arduino board are really close to each other and inside the box.
I think here are my options. What would you recommend to do?
- replace relays with solid state relay
- shield AC wires
- remove power module from the box
- don't use the same power module for relays