Tim Mikkelsen's Arduino Projects


2016/11 Remote temp and humidity


After doing some SparkFun Thing projects, I wanted to try a  similar, but less expensive foundation - the NodeMCU.  This is a relatively simple remote temperature and humidity sensor project.  The code is derived from my remote hot tub sensor design.

The web page that gets served up has the temperature (in farenheit and celsius) and humidity (in percent).

I used the case from a broken Kidde carbon dioxide sensor.  I took out all of the guts but left the board's 5v power supply.  I used the existing red and green LEDs for 'wifi connected' (red) and 'client access' (green).

This all worked fine, except that the built in power supply and associated LM 7805  heated up the interior so the temperature was quite a bit higher than it should.   This old version are the top 2 pictures.

I updated this into a small plastic case with an external 5V wall power supply with the sensor outside of the case.  This new version is the bottom picture.  This new version are the  I also put in some extra code to make the web page a little nicer (with bar gauges).  I did not use the LEDs on this version, but they are still supported in the code.


  - HiLetgo New Version NodeMCU LUA WiFi Internet ESP8266

  - DHT11 temperature and humidity sensor

  - 2x 390 ohm resistors

  - 2x LEDs (1 red, 1 green)

  - power supply

Total parts cost: Approximately $20

NodeMCU remote temp code