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Topic: Is something wrong with my LCD screen? (Read 2 times) previous topic - next topic

AdamHorton

I just got an Arduino and an LCD screen, and I can't seem to get the LCD to display anything. I've tried getting the HelloWorld demo to work, the one that comes with the Arduino software under the LiquidCrystal library. I've made a video of my setup, and I've also taken a closer picture of my soldering.

http://www.youtube.com/watch?v=JtyFPU34K0I
http://www.adamhorton.com/files/lcd.jpg

I'm able to get the backlight to work, and it looks like the contrast is working. What could be my problem here?

thebigphish

you have an incompatible setup there.

The LCD you are using is not 16x2, as the code library you are trying to make work requires.  The one you are apparently using is 20x4  The LCD (just from looking at it has 20 pins (making it most likely a parallel data bus)...and you have 11 hooked up.  Obtain the data sheet for the LCD you are using, interface that with the arduino you are using with the required hookups, and then find a library which supports your LCD driver chip.


All you are currently doing now is powering the logic circuit and LCD backlight.
yes, have some.

AdamHorton

Thanks for your help.

The display is 20X4 instead of 16X2. I've tried adjusting the lcd.begin statement to account for that but I get the same results.

There are 16 pins on my LCD, not 20 -- I've seen LCDs with 14 pins, without the extra two on the right that control the backlight, but other than that it looks to be the same as other LCDs that I've seen examples of, and they use the LiquidCrystal library. There are even labels on the pins (underneath where the header is on the video) that match up with all of the code examples I've seen.

This is the type of LCD I have: http://www.hacktronics.com/20-x-4-White-on-Blue/flypage.tpl.html

It comes with a tutorial, but no datasheet. Here's a link to the tutorial: http://www.hacktronics.com/Tutorials/arduino-character-lcd-tutorial.html

In that tutorial, there is a code sample that uses the LiquidCrystal library to drive the LCD, it's not all that different from the HelloWorld example I've been using. I've tried using that code example and I get the same results.

Are you sure it's not a problem with the library? Even if it was, I'm not sure where I would go to find a different one...

thebigphish

please cut and paste the sketch you are working, that vid/cam resolution gives me eyestrain.
yes, have some.

AdamHorton

http://www.adamhorton.com/files/lcd_circuit.jpg

The red numbers mean that the pins go to the corresponding pins on the Arduino. "wiper" means that it goes toward the wiper of the potentiometer.

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