Hi.
I made one board that is attached to arduino mega. Board is powered with standard 12V / 1.5A transformer and there are two main power supply's. 12V DC and 9V DC. 9V for arduino board and 12v for coin sorter.
Keypad and lcd are connected directly to arduino pins.
When user enters right code configuration, door opens. Relay is standard 12V / 10A AC relay and one pin of relay is connected over resistor to arduino pin and other part directly to transformer.
Basically everything is working as it should but it looks like that the diode that is hooked up to relay, isn't filtering enough. Almost each time, when the lock is opened, display ( connected directly to arduino ) start to flicker. The lock is pulling 1A.
One college has suggested to set one TVS diode in parallel with lock to solve this problem. Any suggestion what kind of tvs diode should i use in this design and will this work with AC relay ?
Regards !