The microcontroller-based concept was chosen because I wanted to scale the sensor system later to suit other applications. Here is the diagram of my Arduino infrared close ... the D13 signal output ...

In our case Arduino is the master and 3 x TC74 sensors are the slaves. As you can see in the schematic all three TC74 sensors have their SDA and SCL pins connected in series to pin A4 and A5 on ... is ...