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Project Notes

#343 Sensors/DHT11

Reading temperature and humidity with a DHT11 sensor and ESP-01, coding with ESP8266 core for Arduino.



The DHT11 sensor is a very cheap and common sensor that provides readings of:

  • relative humidity: 20-80% ±5%
  • temperature: 0-50°C ±2°C

I’ve used this before with an Arduino - see LEAP#301. This time I’m testing with the most basic ESP8266 board - an ESP-01, which exposes one free GPIO.

Programming Setup

I’m using a LEAP#194 DIYDevBoard to host the ESP-01 module, and a cheap CH340G-based USB to UART adapter. With the correct drivers installed, it shows up in the tty device list.

My host computer is running MacOSX.

Required Libraries

I’m using ESP8266 core with the Arduino IDE, and the Adafruit sensor library to interface with the DHT11:

These need to be installed in the Arduino IDE.

Test Sketch

The DHT11.ino sketch simply reads the sensor every 2 seconds and outputs the readings to the serial port.

Here is a test run:






Credits and References

Project Source on GitHub Project Gallery Return to the LEAP Catalog

This page is a web-friendly rendering of my project notes shared in the LEAP GitHub repository.

LEAP is just my personal collection of projects. Two main themes have emerged in recent years, sometimes combined:

  • electronics - usually involving an Arduino or other microprocessor in one way or another. Some are full-blown projects, while many are trivial breadboard experiments, intended to learn and explore something interesting
  • scale modelling - I caught the bug after deciding to build a Harrier during covid to demonstrate an electronic jet engine simulation. Let the fun begin..
To be honest, I haven't quite figured out if these two interests belong in the same GitHub repo or not. But for now - they are all here!

Projects are often inspired by things found wild on the net, or ideas from the many great electronics and scale modelling podcasts and YouTube channels. Feel free to borrow liberally, and if you spot any issues do let me know (or send a PR!). See the individual projects for credits where due.