Introduction: Interfacing 20x4 LCD With Arduino

Picture of Interfacing 20x4 LCD With Arduino

A liquid-crystal display (LCD) is a flat panel display, electronic visual display, or video display that uses the light modulating properties of liquid crystals. Liquid crystals do not emit light directly.
Here, in this i'ble we're going to use a monochromatic 20x4 alphanumeric LCD. 20x4 means that 20 characters can be displayed in each of the 4 rows of the 20x4 LCD, thus a total of 80 characters can be displayed at any instance of time.

Step 1: Material Required

Picture of Material Required

List of requirements is as follows:

1. Arduino/or any other clone

2. 20x4 LCD

3. Breadboard

4. 1k, 220R Resistors

5. Connecting wires

Step 2: LCD-Pinout

Picture of LCD-Pinout

The LCD we are using has 16 pins. Description of each pin is as follows:

Pin No Symbol Level Description

1 VSS 0V Ground

2 VDD 5V Supply Voltage for logic

3 VO (Variable) Operating voltage for LCD

4 RS H/L H: DATA, L: Instruction code

5 R/W H/L H: Read(MPU?Module) L: Write(MPU?Module)

6 EH H->L Chip enable signal

7 DB0 H/L Data bus line

8 DB1 H/L Data bus line

9 DB2 H/L Data bus line

10 DB3 H/L Data bus line

11 DB4 H/L Data bus line

12 DB5 H/L Data bus line

13 DB6 H/L Data bus line

14 DB7 H/L Data bus line

15 A 5V LED +

16 K 0V LED-

Step 3: Schematic

Picture of Schematic

1. Study the schematic carefully.

2. Place your LCD on the bread board.

3. Make connections as per the schematic.

4. Instead of the potentiometer, you can use a 1k resistor and connect Pin 3 of LCD to Vcc via the resistor.

5. Carefully check whether all the connections are tight and correct.

6. Power up your Arduino via USB and check whether the LCD lights up. If yes, proceed.

Step 4: Code

Picture of Code

There are two options that you can follow, either you can build up your own code, if you know how to or you can use the example code from the built-in Arduino library "LiquidCrystal.h".

I have used the HelloWorld example from the library. You can find this example in Arduino IDE following the path: File->Examples->LiquidCrystal->HelloWorld.

Now connect the Arduino to any of the USB ports and upload the code.
Once the code is uploaded, you must be able to see "hello, world" printed on the LCD.

Step 5: That's All

Picture of That's All


Birajdarnikhil made it! (author)2017-09-02

hello sir ,

i were facing some problems in this project... my lcd dint showing any thing... plzz help me... only back light is ON....

babul786 (author)2017-07-25

You are posting this instruction for 20*4 since you have used 16*2 in your program??

ScottL3 (author)2016-07-07

This is a very good instructable as I have a need to test an 20x4 LCD display that was attached to a smart reprap board.


KaranA20 (author)2016-06-05


kishorekumarr (author)2016-01-29


I am working with 4x20 LCD to select 4 lines plz helpme... i dont have proper datasheet..

Medo best (author)kishorekumarr2016-03-13

lcd.setCursor(x, y);
Set x as the charcter pos. And y for the line..

ebi86 (author)2015-10-12

hi dear

excuse me in page 3 you wrote:

4. Instead of the potentiometer, you can use a 1k resistor and connect Pin 3 of LCD to Vcc via the resistor.

there is a problem. pin 3 can be connected to GND via a resistor; not to vcc


apoorveinstein (author)ebi862015-10-31

It can be done.

The pot acts as a voltage divider, if I connect Pin3 to Vcc via a resistor, it'll still work as the Pin3 will have a floating ground. Thus, it solves the purpose of voltage division.

ebi86 (author)2015-10-12

please write a sample code in bascom version thanks

LeonardoB3 (author)2015-03-07

Estimado, lo hice y no me funciona, el diagrama es exacto.

Hasta probé modificar el

lcd.begin(20, 4);

Alguien me dijo de modificar la librería, vos lo hiciste o te anduvo de primeras?.


LeonardoB3 (author)LeonardoB32015-03-07

Ya lo resolví, le saqué el potenciómetro y le puse una resistencia de 10k.


dorgan1983 (author)2015-01-06

Save yourself some I/O pins and get an I2C version

I2C and serial versions of LCD does save pins but for beginners, I think this is better to use and understand.

About This Instructable




Bio: An electronics enthusiast... #Complexity simplified
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