How to Interface the 16×2 LCD with the Raspberry Pi 4

The LCD stands for “Liquid Crystal Display” and is used to display the characters or strings on its screen, moreover, there are different types of LCD like 16×2 and 16×4 but we will consider the 16×2 LCD in this guide as it is easily available. The 16×2 LCD is used in many applications like to display the strings for advertisement purposes and to display the time on the digital clocks.

In this write-up, we will discuss the interference of the 16×2 LCD with the Raspberry Pi 4 and also display some strings on the LCD.

How to interface the 16×2 LCD with the Raspberry Pi 4

To connect the 16×2 LCD with the Raspberry Pi 4, we will need the following electronic components:

Breadboard
1 16×2 LCD
Jumper wires
1 Potentiometer

The circuit diagram of the circuit of interfacing the 16×2 LCD with the Raspberry Pi 4 is:

First, we will place the Raspberry Pi, a potentiometer, and the 16×2 LCD on the breadboard:

Now with the help of jumper wires, we will connect the 16×2 LCD with the GPIO pins of Raspberry Pi 4 according to the table:

GPIO pins of Raspberry Pi	BCM pins of Raspberry Pi	LCD pins
GPIO 22	15	RS
GPIO 24	18	RW
GPIO 23	16	E
GPIO 9	21	D4
GPIO 25	22	D5
GPIO 11	23	D6
GPIO 8	24	D7
Ground	6	K, VSS
5V	2	VDD, A

Other than these connections, the Vo pin of the LCD is connected to the output pin of a potentiometer and the remaining two pins of potentiometer are connected to the 5V and the ground of the Raspberry Pi.

How to download the RPLCD library in the Raspberry Pi 4

To interface any LCD either its 16×2 or 16×4, we have to download the library of RPLCD which we can download by using the wget command:

$ wget -c https://github.com/dbrgn/RPLCD/archive/refs/heads/master.zip

When the command executed successfully, a zip file will be downloaded with a name of “master.zip”, to unzip it, we will use the command:

$ unzip master.zip

Now, we will go to the unzipped folder, RPLCD-master, directory using the cd command:

$ cd RPLCD-master

What is the Python code to connect the 16×2 LCD with Raspberry Pi 4

Once we are in the “RPLCD-master” directory, we will create a Python file with the name of “LCD.py” to write the Python script to interface the LCD with Raspberry Pi 4 using the command:

$ nano LCD.py

Type the following python code to display the “LinuxHint” on the 16×2 LCD:

import RPi.GPIO as GPIO
#import the RPi.GPIO library

from RPLCD.gpio import CharLCD
#import the CharLCD library from RPLCD.gpio

GPIO.setwarnings(False)
#to ignore the warnings

lcd = CharLCD(pin_rs = 15, pin_rw=18, pin_e=16, pins_data= [21,22,23,24],
numbering_mode = GPIO.BOARD, cols=16, rows=2, dotsize=8)
#declare the LCD pins with GPIO pins of Raspberry Pi 4

lcd.clear()
#clear the screen of LCD

lcd.write_string("It’s LinuxHint")
#display the text on 16x2 LCD

Explanation of code: In the above code, we have imported the libraries RPi.GPIO and RPLCD.gpio from the CharLCD. Then we set the function of set.warnings to False to ignore the warning of LCD and initialize the 16×2 LCD. Then clear the display of the 16×2 LCD and display “It’s LinuxHint”.

Note: During the initialization of the LCD, we set numbering_mode= GPIO.BOARD because we are using the BCM nomenclature of the pin number of Raspberry Pi which is mentioned in the above table.

To compile and execute the script of the file “LCD.py”, we will use the command in the terminal of Raspberry Pi:

$ python LCD.py

The hardware working of the above project of interfacing the 16×2 LCD with the Raspberry Pi 4 is

Conclusion

There are different types of LCDs that can be interfaced with Raspberry Pi. They are used to display the characters, strings, and any sensor output on its screen. In this write-up, we have configured the LCD with the Raspberry Pi 4 and displayed a string on its screen using the Python code.

How to Interface the 16×2 LCD with the Raspberry Pi 4