16×2 LCD with I2C Backpack (PCF8574)
by Generic
SKU: PSA-CMP-LCD1602
No reviews yetTypical India street price
₹90–₹180
Two-line character display for scores, IP address, sensor values.
Interface: I2C
16×2 backpack on the LCD I2C overlay (D2/D1).
SDA → D2, SCL → D1
Blockly: lcd_print, display_print
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Concept
A 16×2 character LCD shows two lines of text. With a PCF8574 I2C backpack, wiring collapses to SDA/SCL — ideal for scores, IP addresses, and menus.
A little theory
HD44780-compatible controllers store 5×8 character glyphs in CGROM. Data is written as 4-bit nibbles; the backpack bit-bangs those lines over I2C. Address is commonly 0x27 or 0x3F. Contrast is an analog pot on the backpack. Backlight LEDs draw noticeable current. In the classroom, treat 16×2 LCD with I2C Backpack (PCF8574) as a beginner part using I2C. Typical India street price is about ₹90–₹180. Always verify voltage and pin labels on your exact module — silk screens vary across clones. Start with a datasheet or trusted learn guide, power the part correctly, share GND with the MCU, and test with a simple blink/read sketch before building the full project. Measure voltages with a multimeter when something fails, and keep actuator current off the MCU regulator.
How it works in a project
5 V, GND, SDA, SCL. LiquidCrystal_I2C lcd(0x27,16,2); lcd.init(); lcd.print("Hello"). If blank, scan I2C address and twist contrast.
Classroom & project use
- Kit IP / status display
- Quiz scoreboard
- Sensor readout
- Simple menus
Buying in India
Precautions
- 5 V display — use level shifting with strict 3.3 V MCUs if needed
- Do not reverse VCC/GND
- Set contrast before declaring the LCD dead
Specifications
| Size | 16×2 chars |
| Bus | I2C 0x27/0x3F |
| Controller | HD44780 compatible |
| Backlight | LED |
| Category | Displays |
| Difficulty | Beginner |
| Voltage | 5V |
| Interface | I2C |
Pinout
GND | VCC | SDA | SCL (backpack); address 0x27 or 0x3F
