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LCD1602 (I2C) on a Raspberry Pi 4B: Wiring & Python

Wire an I2C-backpack 16x2 LCD to a Raspberry Pi 4B using just 4 wires, and print text to it with Python — wiring, code, and common fixes.

Try this directly in the free Raspberry Pi 4B simulator — no hardware or signup required. New to the GPIO header? Start with the interactive pinout guide.

What you’ll need

Raspberry Pi 4B
LCD1602 (I2C) — the I2C-backpack variant, not the parallel one

Step by step

Drag Raspberry Pi 4B onto the Canvas.
Drag LCD1602 (I2C) onto the Canvas.
Hover over its pins to confirm labels: GND, VCC, SDA, SCL.
Wire it up: GND → Pi's GND pin. VCC → Pi's 5V pin. SDA → Pi's SDA pin. SCL → Pi's SCL pin.

from RPLCD.i2c import CharLCD
lcd = CharLCD(i2c_expander='PCF8574', address=x27, port=1, cols=16, rows=2)
lcd.write_string("Hello ZOLB!")

What “working correctly” looks like

Text appears on the simulated 16x2 display, matching what your script wrote — same visual result as the Parallel variant.

If something’s wrong

Import error, or nothing happens at all → the library path above may need adjusting to match what this component actually expects.
Text appears garbled → check the I2C address — 0x27 is the common default; confirm against this component's settings panel.

More component tutorials are in Learn.