AVR-Chat

AVR switchs on/off a 5V relay using ULN2003. The relay commands to
220V AC contactor, which finally runs motor pumps.

All the circuits are placed in a metal box, and as far as I see, the
spark from contactor coil disrupts LCD display or MCU itself.

I used a serial RC in parallel with contactor coil, which lower spark
effectively. Yet this is not enough. What elese can I do?

Many thanks in advance.

Behrooz Hariri