PCF8575 IO Expander Module I2C To 16IO Integrated Circuits For arduino Features: Available library: PCF8575 Working voltage: 2.5 - 5.5VDC Working current: 100mA(MAX) I2C address: 0x20(default),can be modified by soldering A1 and A2 selection pads. 16 individually addressable pins. Each pin configurable for input or output Open-drain interrupt output pin for input change interrupt. Great for other MCU to control simple relay, buzzer, button, led.