trouble with lcd 1602

fist line of lcd shows a white line

i have tried hooking up the lcd and slightly different ways and using different sketches but it only shows the white line at he top. i am using a 50k pot and i think that is why i have a hard time setting the contrast

The 50K pot should work correctly. At one end the display will be blank and at the other end the row of blocks will be very dark and the second row may be visible. The correct setting is where only the first row is visible, and not too dark.

If your display is not showing any characters when your sketch is running then you have to make sure that the six wires that go between the Arduino and the LCD module are connected properly. You must also be sure that pin 5 of the LCD is connected to GND.

If you still can't get it working then we need a photo of your connections and a copy of your sketch.


i went back to the original sketch and wiring and now i don't even have the white blocks across the top row of the lcd

this is a picture

Try soldering the header to the LCD module .


A currently unrelated problem that you may run into in the future may be caused by the fact that your horizontal power busses do not run the full length of your breadboard.

You may be unaware that since the red and blue lines are not continuous neither are the corresponding bus connections. You actually have eight half-length power busses rather than four full-length ones.


As floresta says, your problem is now only too obvious. And nothing like the first - or even the sixth time we have seen it here!

You haven't even connected your display to the breadboard!

Some connections are touching, clearly others are not. No wonder it does not work - and does different things each time.

You have to actually connect the pins to the display - by soldering.

soldering helped and i didn't know that by bread board was split in half
it works now