NodeMCU-BME280-MQTT-Energy-Saving

This sketch publishes temperature humidity and barometric pressure data from a bme280 device to a MQTT topic. It also publish the battery voltage but you have to install a voltage divider. (see https://en.wikipedia.org/wiki/Voltage_divider if needed).

    Vin <---o
          __|_
         |    |
         | R1 |
         |____|
            |                                       R2
            o-------> Vout --> A0         Vout = --------- x Vin
          __|_                                   (R1 + R2)
         |    |
         | R2 |                           Vout MUST BE < 1 V !!!
         |____|
            |                       (I choose R1 = 470 k and R2 = 100 k
           _|_                    but feel free to choose your own values!)
           /// Gnd

This sketch goes in deep sleep mode once the data has been sent to the MQTT topic and wakes up periodically. (configure SLEEP_DELAY_IN_SECONDS accordingly).

Hookup guide is in the .ino file

This sketch is the result of the compilation of some diyers and arduinoers. Thanks to them! And of course it is in public domain.

Enjoy!