16x2 Character LCD (I²C)
A two-line text display; the I²C backpack drives it with just two wires.
How it works
A 16x2 character LCD (HD44780) shows two rows of 16 characters — perfect for menus, readouts, and status. Driven directly it needs about six pins, which eats up your board.
The common fix is an I²C backpack (a small PCF8574 board soldered on the back) that reduces it to four wires: VCC, GND, SDA, SCL. Talk to it with the LiquidCrystal_I2C library. The I²C address is usually 0x27, sometimes 0x3F.
Pins
- VCC
- To 5V.
- GND
- To GND.
- SDA
- I²C data — to A4 on an Uno.
- SCL
- I²C clock — to A5 on an Uno.
Ratings
- Size
- 16 columns × 2 rows
- Voltage
- 5 V
- I²C address
- 0x27 (or 0x3F)
Tips
- If you see only blank boxes or nothing, turn the little contrast pot on the backpack.
- Wrong address? Run an I²C scanner sketch to find it.