Hey there, I'm a newbie in electrics.

Standard Arduino Duemilanove.

relay module, the arduino brick.

serial-enabled LCD, basically an additional controller for the LCD has 3pins, Vcc, GND, S (serial input).

PROBLEM: Whenever I activate my relay using an output pin, the LCD display blinks rapidly as though the contrast is set lower (Not the backlight, backlight operates normally). When I set the output pin controlling the relay to LOW again everything reverts to normal.

Note: My sketch includes an update of the LCD every loop() cycle, but does not clear the LCD screen.

So I'm suspecting too much current draw from the arduino for the Relay?

Pls anyone, enlightenment?

Do you have a snubber diode across the relay? Edit: Forget that (well, don't forget the diode) - it happens when you energise the relay, and for as long as the relay is energised? Sounds like a power supply problem.

Yup, as long as the relay is energised.

the relay comes in a module. I assume the diode comes along in the module, because I couldn't find its datasheet.

Anyway, I tried adding an additional diode between its Vcc and GND pins. As expected, it doesn't solve the problem.

Is there a way to solve this problem? adding a transistor somewhere? I have no electrical backgrounds. :P

How were the additional diodes added? Need some picture of your setup.