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Complete the build

Our own DIYKIT board was made for this — plus what it is usually wired or ordered with.

DKB-0004-B

GPIO Card for Raspberry Pi 4 & 5 - 40-Pin Pinout Reference

53 in stock

// 01

Description

This is the classic 16x2 character LCD with the I2C backpack already soldered on. Instead of 16 pins and six or more wires, it connects with four: GND, VCC, SDA and SCL. Plug it into the I2C bus of an Arduino, ESP32 or Raspberry Pi and print text with the LiquidCrystal_I2C library.

The display is the HD44780-compatible 1602A with a blue backlight and white characters. The PCF8574 backpack carries the contrast potentiometer, a backlight jumper and the A0–A2 address pads, so several displays can share one bus.

What it does

Shows sensor readings, menus, clocks and status messages in two lines of 16 characters
Frees up GPIO pins – the whole display runs on the two I2C pins
Drop-in replacement for the parallel LCD 1602 in any Arduino tutorial, with no soldering
Shares the bus with other I2C devices (RTC, sensors, OLED) on the same two wires

Specifications

Specification	Value
Display	16 columns x 2 rows, 5x8 dot characters
LCD controller	HD44780 compatible (1602A)
I2C expander	PCF8574 backpack, soldered to the LCD
I2C address	0x27 default (0x3F on PCF8574A boards); A0-A2 pads give 8 addresses
Supply voltage	5 V
Current	About 20-25 mA with backlight on
Interface	I2C (SDA, SCL), 100 kHz standard mode
Pins	4: GND, VCC, SDA, SCL
Backlight	Blue LED backlight, white characters, jumper to disable
Contrast	Potentiometer on the backpack
Module size	80 x 36 mm, about 20 mm high with backpack
Viewing area	64.5 x 16 mm
Operating temperature	0 to 50 C
Weight	About 40 g

Wiring

Pin	Connect to	What it does
GND	GND	Ground
VCC	5 V	Power for the LCD and backlight
SDA	Arduino UNO/Nano A4, Mega 20, ESP32 GPIO 21, ESP8266 D2, Raspberry Pi GPIO 2	I2C data
SCL	Arduino UNO/Nano A5, Mega 21, ESP32 GPIO 22, ESP8266 D1, Raspberry Pi GPIO 3	I2C clock

The backpack’s pull-up resistors are tied to 5 V. On a 3.3 V board (ESP32, ESP8266, Raspberry Pi) use a bidirectional I2C level shifter to keep the SDA and SCL lines within the board’s limits.

Getting started (Arduino)

Install the LiquidCrystal I2C library (Library Manager, by Frank de Brabander)
Wire the four pins as in the table above
Open File → Examples → LiquidCrystal I2C → HelloWorld, set the address to 0x27 (or 0x3F) and upload. If the screen stays blank, turn the contrast potentiometer slowly until the characters appear
Still nothing? Run an I2C scanner sketch – some batches use address 0x3F instead of 0x27

Raspberry Pi

Enable I2C in raspi-config, connect through a level shifter, then i2cdetect -y 1 shows the display at 0x27. The RPLCD Python library drives it with a few lines of code.

// 02

Specifications

Display 16 columns x 2 rows, 5x8 dot characters

LCD controller HD44780 compatible (1602A)

I2C expander PCF8574 backpack, soldered to the LCD

I2C address 0x27 default (0x3F on PCF8574A boards); A0-A2 pads give 8 addresses

Supply voltage 5 V

Current About 20-25 mA with backlight on

Interface I2C (SDA, SCL), 100 kHz standard mode

Pins 4: GND, VCC, SDA, SCL

Backlight Blue LED backlight, white characters, jumper to disable

Contrast Potentiometer on the backpack

Module size 80 x 36 mm, about 20 mm high with backpack

Viewing area 64.5 x 16 mm

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// From Displays