• Vin - this is the power pin. Since the sensor chip uses 1.8VDC, we have included a voltage regulator on board that will take 3-5VDC and safely convert it to 1.8VDC. To power the board, give it the same power as the logic level of your microcontroller - e.g. for a 5V micro like Arduino, use 5V.
• 1V8 - this is the 1.8V output from the voltage regulator, you can grab up to 100mA from this if you like
• GND - common ground for power and logic

• SCL - the I2C clock pin, connect to your microcontroller's I2C clock line.
• SDA - the I2C data pin, connect to your microcontroller's I2C data line.
• STEMMA QT - These connectors allow you to connectors to dev boards with STEMMA QT connectors or to other things with various associated accessories

INT - the interrupt pin. It is an open-drain interrupt. To use, connect the pin to a GPIO pin on your microcontroller.

Above the left STEMMA QT connector there is a small red ON power indicator LED. When the breakout is powered this LED will turn on. 

On the back of the TCS3403 breakout there is a jumper with a small trace between two pads that can be cut to disable the ON power indicator LED on the board.