Temperature and Humidity Display

This project was one of my first to combine my (then) new Arduinos and 3D printer. The Temperature and Humidity display has turned out to be a very useful project, and has been in continual use for several years.

Background: Rather than run a tumble direr, with its associated noise and expense, we prefer to hang laundry up to dry in a utility room, and make occasional use of a dehumidifier if needed. This little project lets us see drying progress at a glance, and if we need the dehumidifier to hurry things along ... and perfect for justifying the kit to SWMBO.


Straightforward, and if you have an Arduino starter kit then you probably have everything that's needed.


  • Display
    • Display SCL to A5 on theArduino Uno
    • Display SDA to A4
    • Display Gnd to any G (Gnd) pin on the Arduino
    • Display Vcc to 5V
  • DHT11
    As mentioned above, DHT11s can have different pinouts. It doesn't matter which one you have, however pay attention to what's printed on the board or data sheet.
    • VCC to any 5V on the Arduino
    • GND to any G (Ground/GND) on the Arduino
    • Data to Pin 4 on the Arduino


The code is based on THIS PROJECT .. thanks!

You can download my sketch HERE.

3D Print a Case

Apart from a few bits of code tinkering, the only real addition I've added to the Hive Mind is this enclosure.

If you have a 3D printer, you can download the STL file to print a case (right click and save as).

The display and arduino Uno fit on the pegs, and to secure you just need to flatten them a little with a soldering iron. The two parts are a friction fit.

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