The default connector as the following pin out
- +12V (not connected)
- SCL (PWM)
- SDA (I/O)
- A6 (GND)
There is the possiblity to have an internal pullup so that if we connect a LDR between the ground and A6 it should be possible to measure the light intensity.
We can also connect a one-wire temperature probe DS18B20 connected to SCL. We will also have to connect a 4.7kΩ between +5V and SCL.
Finally we can connect the power supply between the +5V and the GND. The power supply may be anything between 3.7 and 6V.