Pin Definition: Power supply pin: VIN - Power input pin. Voltage input range 3-5V; 2v8 - Output port, 2.8V output voltage generated by the on-board voltage regulator processing the input voltage of VIN; GND - Power supply ground; I2C communication pin: SCL - I2C clock pin, connected to the master SCL; SDA - I2C data pin, connected to the master SDA; Control pin: GPIO - Pin that the sensor uses to indicate the data ready. Note that the pin output is 0-2.8V high and low level. This pin may not be applied to boards such as for Arduino (These boards are 3.3 or 5V high level), need to add level conversion if applied. SHDN - Shutdown pin of the sensor. By default it is pulled high. There is a level conversion diode so you can use 3-5V logic on this pin. When the pin is pulled low, the sensor enters shutdown mode.