The LCD display is an I2C device. Make sure to read our separate I2C instructions for other important details on wiring up any I2C device.
Here are instructions on making the LCD displays work in particular. Some specific details that apply to us are:
- First install the Newliquidcrystal library, as linked in the above instructions. Specifically, download the zip file from that site somewhere onto your computer. Then, in the Arduino IDE, go to the Sketch menu, then choose Include Library, then Add .ZIP library. Find and select the zip file you downloaded.
- We seem to have "LCD Version 1." Follow the instructions and use the sample code for that LCD screen in particular.
- There's a small potentiometer (phillips shaped screw) on the back of the LCD display that controls the contrast. If it is not set correctly, you won't see anything displayed on the screen. Turning it counter-clockwise too far makes all the pixels too light to see. Turning it too far clockwise makes all of the pixels on the screen, including those that shouldn't be on, so dark that you can't distinguish anything. The right value is somewhere in between. It is fairly sensitive; a quarter turn or so seems to go from one extreme to another.