5V LCD brightness has gone down (blank) when 230V AC given to 5V relay ouputs pins

[Arul Raju]

Hello everyone,
I'm using Arduino Mega board on one of my project. The 5V supplied from a PCB (2A rated). A dedicated 5V power supply is used for 2 LCDs.The relay coils are supplied by Arduino 5V pin.

I have used 230V AC connection at relay output (change overs) for tower lamp.

The problem is, when no 230V AC supply is given (i.e no connection) at relay output ends, the LCDs are working fine. But when 230V supplied, LCDs start loosing brightness and at some point, it has gone to blank (no readings).

I think there is no relation between 5V power supply and relay 5V supply. I don't know what is the issue. and which causes LCD down?

Can someone help me on this? I appropriate your prompt answer.

Thanks,
Arul

 

[kellys_eye]

Show your wiring.

I trust you haven't connected the mains neutral to the logic ground.....