When use Arduino to make robots or perform interactive media have you found digital IO ports are not efficient? Arduino UNO and Leonardo often face this problem. How can we make use of existing resources to expand sufficient Arduino ports? Actually we are able to solve this problem through the Arduino I2C IC GPIO Module can achieve communication through Arduino two IIC data lines (SDA / SCL) thus convert the readable and writable 16 channel digital I / O port. In addition 8 modules can be simultaneously in parallel and each module can be set to different IIC address through which you could parallel multiple modules for data acquisition and control according to the demand of project digital ports. A total of 128 digital ports are spared double of MEGA2560. If you cant use I2CSPI or other protocols it is necessary to equip with an expanded version of IO Application:Data acquisition and control Drive digital equipmentsLEDRelaysSensorsKeypad and so on