ESP8266
One of the supported Node MCUs in the project is the ESP8266. It only has one analog input, so to make it possible to use two analog sensors, this design uses two NPN transistors to select the sensor which is being read.
The schematic below illustrates the correct way to wire the ESP8266 Node MCU on a breadboard. The Fritzing project file can be found within the repository, if you wish to tinker with it.
Warning: the schematic uses a BEC transistor (the pins are base, emitter, and collector), while the 12V switch uses a BD243 transistor, which is BCE (the pins are base, collector, and emitter). Please make sure you connect the wires to the correct pins on your transistor.
