Co2 Detector

After reading this article (ES) I started to think about creating my own sensor board. I searched which sensor to use and the SGP30 seemed a good option to me. Then, I did a few tests, I modified the code of another project and then I designed a PCB and later on I  built two prototypes which are currently working in my house. The device uses a mqtt queue to send data to an IoT gateway (a minipc running Home Assistant in my case). In addition to that, there are three LEDs to show what is the current state of the air based on CO2 PPMs:

  • Green light is shown if there are less than 600 PPM of CO2.
  • Yellow light if there are between 600 and 800 PPM.
  • Red when the CO2 is greater than 800.

The source code and the PCB design (made in Kicad) can be found here. In January, the project was certified by as open source hardware by the OSHWA

The Power Progress Community non profit association is trying to fund a new notebook based on a NXP T208x processor. This organization is accepting donations with the objective of collecting funds to establish a contract with Acube Systems to design the laptop's motherboard. The campaign started last Friday reached a 10% of its goal in 24h.

The objective is not only to build a notebook but to promote the use of Power technologies for home computing as well. We want to create an open computer and certify it as Open Source Hardware if possible. We are commited to distribute all the work performed in the scope of the project as open source, publishing documentation, designs etc.

The circuit in a breadboard

This is a quick example of how to use websockets in an ESP8266 device. I wanted to experiment with websockets and this was a simple way to do it. The device runs the websocket server and its code is very similar to what you can find in this example. On the other side, the client is a Qt (QML) application. I think QML is an easy way of developing applications and the advantage is that you can use the same code in a smartphone or a desktop PC. If you prefer, before reading this article you can find the source code repository here.


  • This source uses Arduino IDE and its standard libraries
  • Additional libraries: arduinoWebsocket
  • QT creator IDE for the client application

Fritzing schematics

MeteoHome is yet another weather station project using a NodeMCU ESP8266 devboard with DHT22 and BMPP180 sensors. The particularity in this case is the configuration using a captive web portal and the use of MQTT to send the information to a server. Additionally the machine that gathers all the data runs Home Assistant which is the responsible of showing the current status of the sensors and historical graphs. You cab grab the source code of this project here.


  • configuration of WiFi network and MQTT through a web portal
  • Deep sleep mode included for being powered by battery
  • Temperature, humidity and air pressure measurements
  • Possibility of being used with Home Assistant
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