The instructions and wiring on this page is based off of ladyada's wonderful Character LCD wiring guide, but updated for Fritzing.
Some 16x2 LCDs may come assembled, meaning the header is already soldered on:
We also have some that are unassembled with an unsoldered header:
If your LCD is assembled, you can skip these next steps and proceed directly to wiring it up. Otherwise, follow along below.
Soldering is a very useful skill in the realm of electronics. It's the process of joining two metals together, using another piece of metal (also known as solder) between them. If you have never done this before, Bill Earl wrote an awesome visual guide entitled Adafruit Guide To Excellent Soldering which will get you off the ground, fast. If you would prefer to watch a video, Collin's Lab covers soldering, too:
The 16x2 LCD is not that hard to solder, but it does have a lot of pins. We have some advice for soldering these like a pro:
Start by plugging your 16x2 LCD and header into your breadboard.
Then, (with a medium-level of heat, dont make your iron too hot!) start soldering Pin 1 to the header. Next solder Pin 16. This will "tack" the header to the LCD, making soldering the rest of the pins easier.
Now, go solder all the other pins!
Messed up? Issues with your header? Soldering is very fix-able. It'll just take time. Check this guide for your mistakes, and correct them before moving on.
First, plug your LCD into the breadboard. Then, connect the +5V Pin to the power rail and the GND Pinto the ground rail.
Let's check it's power. Connect your Metro or Metro Express to power. You should see the LCD light up. Some low-cost LCDs don't come with a backlight.
If you have one with a backlight and if you don't see it lighting up, go back and check over your wiring.
Next, let's place the contrast potentiometer to the left of LCD Pin 16. You can place it anywhere on the breadboard you'd like, but the next CIRC has it placed to the left of LCD Pin 16
Connect one of the outer pins of the potentiometer to the power rail. Connect the other outer pin to the ground rail. It doesn't matter which goes where, the other pins are interchangeable as long as one goes to power and one goes to ground.
The middle of the potentiometer (the wiper) connects to LCD Pin 3
LCD Pin 1 connects to the ground rail. LCD Pin 2 connects to the power rail. These pins are the logic of the LCD.
Before moving on, we'll perform a small test to make sure the wiring is correct. Plug in your Metro or Metro express and twist the potentiometer. You should see black rectangles appear on the first line of the LCD. If you don't see this, check your wiring before moving on.
The RW Pin is not required for this guide, as we are only writing to the display. Connect LCD Pin 5 to the ground rail.
Next, we are going to connect the RS Pin. We used a blue wire to connect LCD Pin 4 to Metro Digital Pin 7
Next is the first of the data pins, DB7. We used a white wire to connect LCD Pin 14 to Metro Digital Pin 12
This is what you should have on your desk, proceed to the code section after double-checking your wiring: