The MCP23017 I/O Port Module adds 16 programmable I/O pins per chip and can be chained to eight devices on a single I2C bus, each with a unique address. Housed in durable ABS plastic, it delivers reliable performance across a range of environments. The module uses a simple twowire I2C interface to your main controller, reducing wiring complexity and conserving microcontroller I/O pins. Key benefits Expand I/O capacity without tying up MCU pins Scales up to 8 devices on one I2C bus with unique addresses Simple twowire I2C interface for easy wiring and fast setup Robust ABS housing for long term reliability Configurable I2C addresses for flexible system design Compatibility and build Works with common microcontrollers and SBCs that support I2C, including Arduino, Raspberry Pi, ESP32, and ESP8266 Compact, breadboard friendly form factor with standard header spacing Performance and interface Each MCP23017 provides 16 I/O pins per chip; total expansion is easily achieved by adding more chips Addresses configurable via A0 to A2 pins to support up to 8 devices on one bus Designed for low pin usage while providing dependable digital I/O control Use scenarios Arduino projects: drive LED matrices, button panels, or relay modules with minimal MCU pins Raspberry Pi home automation: expand GPIOs for sensors, relays, and displays on the I2C bus Robotics and embedded systems: add additional digital inputs/outputs for sensors and actuators without complexity on the main controller