20x4 White on Blue lcd help.

Forum 2005-2010 (read only) Hardware Troubleshooting
1

So I bought a White on Blue LCD 20x4 from Hacktronics. Using there code I hooked i up to all the pins necessary (according to them). It lights up but it doesn't display any text, Except for on lines 1 and 3 it displays white boxes all the way across. Please help me get this sorted out.

EDIT: Also, It suggest on there website to reset the board a few times I tried that with no luck.

I have the Arduino Duemilanove with the ProtoShield on top.

2

Can you post a picture of your wiring?

Someone was having a similar problem, and it turned out the Contrast was too high. Are you using a Potentiometer on the Contrast pin? If so, turn it up/down to see if anything changes.

3

Well, I have fixxed it simple issue with my wiring. I swore I wired it right.

That was taken about 3 minutes ago. I have just took the potentiometer out and replace it with a 1k resistor [Brown, black, red] and so far so good. I just didn't really look across the forums for it. My mistake

4

happens to everyone (and HELLO!!!)

5

Hello to you all, as you can see I'm very new to the Arduino I just got my first yesterday. :smiley:

6

tehbeetus:

I have just took the potentiometer out and replace it with a 1k resistor

Just curious - how do you replace a three lead potentiometer with a two lead resistor?

Don

7

Just curious - how do you replace a three lead potentiometer with a two lead resistor?

Probably +5V to one leg of resistor, the other leg to Vo pin.

8

TchnclFl

Probably +5V to one leg of resistor, the other leg to Vo pin.

I doubt it.

Don

9

No one end to Ground the other to the contrast pin is how I did it. Works nicely.

10

I doubt it.

No one end to Ground the other to the contrast pin is how I did it. Works nicely.

My mistake :P.

11

No one end to Ground the other to the contrast pin is how I did it. Works nicely.

That's what I thought. This connection is effectively the same as grounding Vo which works nicely on some displays. If you try different resistor values (within reason) you will see that they all give the same result. You might prefer the results from a properly adjusted potentiometer.

Don