AirCO2ntrol Mini backplate with Wemos D1 Mini

This is a replacement backplate for a TFA Dostmann “AirCO2ntrol Mini” CO2 sensor that includes a separate compartment to hold a Wemos D1 Mini connected to the sensor's debug port through a passthrough slot. The ESP allows you to put the sensor on your network and pipe the sensor data into your existing home automation setup. 

This backplate design will probably also fit other incarnations of the same sensor housing. It was inspired by this thing by Stefan Kern, and created as in that design the heat of the ESP was negatively influencing the sensor's readings. The separate compartment seems to have solved this for me.

While it isn't the focus of this entry, in case you are wondering how to use a Wemos D1 Mini with the sensor, how to wire things together and what to flash, you can read more about this on my blog.

Part list

• 1 x Backplate
• 1 x Backplate Lid
• 2 x M3x14mm bolts
• 2 x M3 nut

Use the bolts and nuts to screw the lid to the backplate after inserting the ESP.

How this was designed

This thing was designed in FreeCAD Linkstage, version 2022.01.11, and the design process was streamed live on Twitch. Recordings of the streams are available on YouTube: