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Author Topic: HD44780 16x2 LCD won't work with my Uno  (Read 1528 times)
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Hi guys,

I have this HD44780 16x2 LCD and my arduino uno, im following this guide trying to wire it up with a 10k potentiometer:

http://learn.adafruit.com/character-lcds/wiring-a-character-lcd

I get the lcd backlight on but the resistor does nothing, i tried changing it with other 1K and 100K resistors and still no effect.

Help please?

Picture of the setup, sorry if its a bit messy:


Sharon
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Edmonton, Canada
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Make sure you have the same pin out as in that tutorial, take your time reading the following tutorial:

http://tronixstuff.wordpress.com/2011/01/08/tutorial-arduino-and-monochrome-lcds/
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gnusci

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I just wired up my first LCD panel today. I too could not get it to work until I followed the example at http://www.hacktronics.com/Tutorials/arduino-character-lcd-tutorial.html. The 16x4 LCD I am using is this one http://imall.iteadstudio.com/eone-high-cost-effective-1604-characters-lcd-blue.html.

Hope this helps.

Scott
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Hi Scot,
In the scheme you gave me : http://www.hacktronics.com/images/arduino_lcd_connections-lg.jpg
Why and how is the resistor connected to pin 1? what if i use a poteniometer? it seems wierd.

Gnusci,
I would rather have a picture then a sketch of the wiring, i tried the one you gave me but still no luck. its as if the resistor does nothing, and when i upload the code i cant see anything either (after i connect all the data wires)
« Last Edit: March 28, 2013, 02:34:27 pm by sharonf » Logged

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Solved,
the trimmer had to be pulled all the way
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The resistor (or pot) is to adjust the display contrast. Once you set it with a potentiometer, you can remove the pot and put in a fixed resistor instead.
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The resistor (or pot) is to adjust the display contrast. Once you set it with a potentiometer, you can remove the pot and put in a fixed resistor instead.

And how would you do that?  All of my potentiometers have three terminals but my resistors have only two.

Don
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The resistor (or pot) is to adjust the display contrast. Once you set it with a potentiometer, you can remove the pot and put in a fixed resistor instead.

And how would you do that?  All of my potentiometers have three terminals but my resistors have only two.

Don

I guess once you know the right resistence for your lcd screen you dont need 3. I think you connect the resistor between the right lcd pin (pin 3) and the ground. Someone correct me if im wrong.
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Someone correct me if im wrong.
You are wrong.  You should use a voltage divider not a single resistor.  Use either a potentiometer or two resistors.

The display may 'work' using your technique, but it will also 'work' if you just connect pin 3 to GND.  It will work best with the proper connections.


Don
« Last Edit: April 07, 2013, 09:04:17 am by floresta » Logged

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