DHT22 is a small temperature and humidity sensor, easy to use. We can use a Raspberry Pi to communicate with it, and make graphs of temperature and humidity evolution. Material We need: a Raspberry Pi (here the 3B+ version) a good quality SD card (class 10) a power supply for the Raspberry (5V between 2.5A and 3A) the DHT22 sensor a 10 kΩ resistor a breadboard another computer to connect to the RPi using SSH an RJ45 cable RPi installation SD card preparation The easiest way to install the RPi OS is to use the Raspberry Pi Imager software, which allows you to choose the right version of the OS, download it and install it on the SD card.

In a previous Devoxx France conference, Clever-Cloud had a booth where they showed how to use their platform with a small chip that controlled a LED strip, all that communicating through a websocket making the interface with the backend hosted on Clever-Cloud. This project is on Github : https://github.com/CleverCloud/wemos-statsd-example. The cool part is that the LED strip and the chip were distributed as goodies :) I recently found this LED strip in a box, and I wanted to play with it.

The two previous blog posts where about the set up of the blog. Now, I’ll add several small (or not) details, such as tags, legal pages, images, table of content, … File organization I first started by creating Markdown files directly in the content/{en,fr}/post/ directory. But while writing this post, I needed to add images. The default place for site images is in the static/ directory (in which I created the images/ sub-directory).