The ADC breakout board extends the analog inputs to the UPOD. It uses a 10bit analog-to-digital converter to capture the analog voltage (0-5V) from 8 input channels. It can be plugged in to the backside of the UPOD at the header underneath the S100 CO2 sensor. The pinout for the 6 wires are printed on the silkscreen of both the UPOD and the ADC breakout board. Simply connect MISO, MOSI, SCK, D2,GND and V+.