Connecting an LCD to the Arduino

In this instructable we’ll be looking at how to connect a parallel LCD to an Arduino. The LCD that I am using uses the common HD44780 interface.  Many LCDs have this, you can usually tell by the 16-pin interface. You only need to solder 10 of the 16 wires to use the LCD, but this will only enable you to use the 4-bit interface.

 

Materials:

 

Arduino (with USB cable)

 

HD44780-compatible LCD screen

 

10 Jumper wires

1 10k Potentiometer

 

Tools:

 

Soldering Iron

 

Helping Hands (optional)

 

Let’s get started!

Step 1: Connecting the Jumper Wires

     The first step we need to do is connect the pins to the LCD.  For those interested, you can find the datasheet here.
    
     I got my LCD from sparkfun, and you can buy one here.
As I mentioned before, you only need to connect 10 pins.  Solder jumpers to these wires:


Pin 1 - Ground
Pin 2 - +5V
Pin 3 - Contrast Adjustment
Pin 4 - H/L Register Select
Pin 5 - H/L Read/Write
Pin 6 - H/L Enable
Pin 11 - DB4
Pin 12 - DB5
Pin 13 - DB6
Pin 14 - DB7

As shown in the picture below:

Pin 1 to GND
Pin 2 to 5V
Pin 3 to wiper
Pin 4 to Arduino pin 12
Pin 5 to GND
Pin 6 to Arduino pin 11
Pin 11 to Arduino pin 5 
Pin 12 to pin 4
Pin 13 to pin 3
Pin 14 to pin 2

Because we will only be writing, pin 5 will be dropped to ground to show that there will be no reading.  For those who wish to use the backlight, connect LCD pin 16 to GND and LCD pin 15 to +4.2V. 

Connect one side of the pot to GND, the opposite to %v, and the center to LCD pin 3.  Now you're in business.

 

Comments

[us241098]

Hi crocboy!!! I connected my lcd same way as in your instructables and it works.
now i am facing a problem i am newbie to arduino and want to use lcd as output ( actually i want to print different numbers when different tactical switches are pressed ) please help me.
THANKS

[axpence]

note: when the user put %v, he means +5V

[jdoeson]

Awesome instructable!

I was able to get everything running smoothly on my ATmega328 (Arduino Uno) and a TM204A-1 LCD screen I got from Amazon. I thought I would be spending days learning how to figure this out, but after soldering the DIP pins on the LCD I was able to get this up in 30 minutes!

I made a slight adjustment by connecting pins 15 and 16 as "The nerdling" mentioned, in order to get the backlight working. I connected pin 15 of the LCD to pin 13 on my Arduino, and made sure to open the pin (13) via IDE programming. Naturally, pin 16 went to the same ground as the rest.

I also used a mini breadboard for the LCD (the red one) to make things easier.

See the attached photo for my setup.

[irtiq7]

Hi there,

I tried everything but I am still getting those black boxes when I set my potentiometer high.

[waterlubber]

Just replace that pot with a simple wire to ground. Works for me!
(P.S. The boxes are GOOD, its supposed to happen)

[coder512]

What do you mean by the wiper part , i didn't get that !!
Pin 3 to wiper ?????

[Michael_Bell]

the middle pin of your potentometer

Connect either end to +5v and ground, and wiper will be the middle pin

[Jeff_]

followed the guide and i only get some weird signs on it but no hello world

[crocboy]

recheck your pin connections, that's usually the main cause of this issue.

[prateekk]

hi ! can u plz tell me the link to the software with the help of which i can boot a programe/code into my arduino...??
like i hav avr for atmel micro controllers.
plz help!!

[crocboy]

To upload code to the Arduino, use the Arduino IDE: http://arduino.cc/en/Main/Software

[andy70707]

Thanks, great instructable, I just got my arduino today and this was my first project!

[The nerdling]

ardino's are awesome your rate of fun projects will go up by the hundreds

[anselmi]

i wired mine just like this and the lcd wont light up or show any thing
if any one could help me i would really appreciate it

[The nerdling]

have you connected the enable pin to 5v or gnd or pin 5?

[The nerdling]

everyone pin 15 and 16 are the backlight pins.
i connected them into 5v with a 140Ω resistor
if your wondering how i got the ohm sighn i used character map in windows

[heleniovix]

i will try in proto-board.

[Robot Lover]

I set it up right but all i get are boxes. What should i do?

[crocboy]

For the people getting black boxes, you may want to try adjusting the contrast potentiometer.

[Derin]

Help! I did all you said but I only get black boxes on the LCD. What should I do?

[frollard]

May I recommend hooking the backlight led to a pwm pin via a resistor, or with a protection resistor via a transistor (if the backlight pulls too much current for the atmega pin to handle).  Variable brightness ftw!

Good writeup!

[crocboy]

Thanks for the tip!  I'll have to try that out.