i connected serial display in my Arduino UNO , the board is controlling heavy noise motor load through Opto isolators , some times when the AC solenoid valve clicks i am getting junk values in my serial Display (16x2) . if reset the UNO i get clear values in my display , what could be the problem , plz advice . Thanks in Advance . -prag
what could be the problem
I think it is pretty obvious that the noise from your motor is getting to your LCD controller.
Reduce the noise from the motor and shield the LCD controller from any noise that remains.
Welcome to the real world.
when heavy motors get switched there can be electric impulses that disturb all electronic circuits in the near. You can get filters to get this impulses low. Simple version is to use condensators and inductivities. But be careful, the motor may run with 230 or 380 Volts, so dont change there anything when you are not a technician for this. Then better ask one .