HW-171 PCF8574 Blue Plate PCF8574T PCF8574 Module I/OExtension ModuleI2C Techmakers

The HW-171 PCF8574 Module is an I2C-based I/O expansion board using the PCF8574T chip. It allows microcontrollers like Arduino, ESP32, ESP8266, STM32, and Raspberry Pi to add 8 additional digital I/O pins via I²C communication, conserving valuable GPIO on the main board.

Chipset: PCF8574T
I/O Pins: 8 bidirectional digital I/O pins
Interface: I2C (uses SDA & SCL lines)
Operating Voltage: 2.5V – 6V (typically 3.3V or 5V compatible)
Default I2C Address: 0x20 (can be changed with A0, A1, A2 jumpers)
Board Version: HW-171 (Blue Plate PCB)
Size	Compact,: ~20mm x 40mm
Mounting: 4x M2 holes for screw mounting
Pull-up Resistors: Onboard for SDA and SCL lines