I'm trying to hack an induction cooktop by controlling its display board through optocouplers (simulating button presses to increase/decrease heating power). These changes are made on the basis of changes in temperature of the contents of the pan, which I measure using a thermistor based temperature probe (link)
My problem - when I ran this circuit off solderless breadboards, it worked nicely. But now that I've transferred it on to a perfboard and enclosed the display board, the perfboard and the arduino inside a sunmica (A thin plywood laminate that looks nice) lined wooden box, the temperature/resistance readings go all bonkers as soon as I switch on the induction cooktop.
The thermistor still works with relatively much lower noise when I use it off a breadboard. It works with almost zero noise, when I use it on a flame-heated container, instead of an induction cooktop.
What am I missing?
Quick note: this is one of my first perfboards. I used copper wires to wire together everything - the kind you get after stripping off the insulation from single strand wires.
Thanks!
(A schematic and a visual is attached)
