AVR-Chat

JoeT said:
> I was going to go for the PCB shielding next. It does not have a ground
> plane.
> I used a 10k a pull up resistor on int0, I'll try 1k.
> What is a "a snubber network on the contactor" ?

A snubber provides EMI suppression.   Can be as simple as a resistor and a
capacitor.

It sounds your contactor and bell are AC operated, but you haven't put any
suppression network on them yet?

Have you considered using solid-state relays?

Mike