Absolutely Stuck - New to Arduino

Other Hardware Displays
1

So I have my Arduino and a LCD screen.

538×717 112 KB

I got jumpers in there. I have no idea how to connect it to the Arduino Uno. I have watched videos but most just show schematics in which I can't understand. I also don't want to involve a potentiometer.

I just need to know which wires plug where.

2

Welcome!

  1. I would recommend that you solder headers to the LCD as the wires poked through the holes won't be reliable enough.

  2. You will need a pot or at least a bunch of resistors as you will need to set the LCD contrast so you can read it.

  3. I would suggest you learn to read schematics as that is the way the world documents these types of circuits. It is not that hard - each line is a wire and you already know about those.

  4. Have you worked out which the power and data pins are? That is very documented in many places. The +5V goes to the +5V on the arduino and GND to GND.

  5. The rest of the pins are digital pins and they can be connected to any of the arduino digital pins. The key is to tell the loibrary what the connections are when you run the softwar and the connections will be adjusted.

Hopefully this is enough to get you going.

3

Here is an outline of what you have to do.
(1) Get your backlight working. This involves pins 15 and 16 and probably an external current limiting resistor.
(2) Get the contrast working and adjusted properly. This involves pins 1, 2, 3 and a potentiometer.
--> Do not proceed until this is working. <--
(3) Connect the signal and data lines between your LCD and your Arduino. This involves pins 4,5,6,11,12,13, and 14 of the LCD module and any available I/O pins of the Arduino.
(4) Make sure that the Arduino pin numbers in your sketch match the ones you actually used.
(5) Run your sketch.

Don

4

Thank you both! I've learned a lot from both of your replies. I now am making progress!

5

The LiquidCrystal tutorial has a pretty good diagram
of how to connect the wires to an arduino board.

What is missing on that tutorial is how to wire up the backlight.

Here is another tutorial:

--- bill

6

bperrybap beat me to it but the url http://arduino.cc/en/Tutorial/LiquidCrystal shows you step by step on what needs to be done. Upload the sketch and test it out.

7

paulsvang:
bperrybap beat me to it but the url http://arduino.cc/en/Tutorial/LiquidCrystal shows you step by step on what needs to be done. Upload the sketch and test it out.

As Bill said, this tutorial barely mentions the backlight. The problem is that some displays, particularly the 'blue' ones, may look like they are not functioning if the backlight isn't powered.

Somewhere along the line they changed this tutorial (or there is another similar one that I can't find right now) and an important problem is the fact that the tutorial has reverted back to a version that does not emphasize the absolute necessity to ground pin 5 (R/W) of the LCD.

There is one easily overlooked comment about this buried in the program code and the connection is shown on the diagram but we had lots of problems with the tutorial in the past when it didn't call attention to this requirement.

That omission was fixed several years ago but it looks like it was re-omitted somewhere along the line. Oh, well....

Don

[Edit]: A short mention of this requirement to ground R/W was added to the body of the tutorial in the Spring of 2010 by Tom Igoe but there is no mention of the change in the page history.