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Topic: HD44780 16x2 LCD won't work with my Uno (Read 1 time) previous topic - next topic

sharonf

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

gnusci

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/
--

gnusci

ScottMurchison

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

sharonf

#3
Mar 28, 2013, 08:31 pm Last Edit: Mar 28, 2013, 08:34 pm by sharonf Reason: 1
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)

sharonf

Solved,
the trimmer had to be pulled all the way

ScottMurchison

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.

floresta

Quote
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

sharonf


Quote
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.

floresta

#8
Apr 07, 2013, 04:01 pm Last Edit: Apr 07, 2013, 04:04 pm by floresta Reason: 1
Quote
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

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