Build Log: SCD41 CO2 Sensor

CO2 concentration is a proxy for how well a space, especially an enclosed one, is ventillated. To this end I build a quick-n-dirty CO2 sensor using a SCD41 breakout board from pimoroni and bits and pieces I had in the workshop.

Took the opportunity to practice making enclosures, especially for an irregularly shaped circuit. The enclosure was designed in FreeCAD by taking a picture of the circuit then importing it as a reference image. After correct for scale the designed enclosure was reasonable accurate, needing only some small tweaks to dimensions to correct forperspective distortion. The result was then 3D printed on my FF Creator Pro.

The enclosure provides openings for a button (currently unused), a "cage" for the CO2 sensor, display and micro-USB port.

In addition to practicing painting techniques, I also wanted to try new ways of "labelling" my projects. Water-slide decals are widely used in model kits, and it turns out you can buy blank sheets with which to make your own decals with! I picked a cheap'ish option off Amazon. Just search for "water slide decal clear laser". Once they arrived it was a simple matter of designing the decals in inkscape, printing it out and cutting them to size. To complete the build, a plastic primer was applied, followed by colour coats, then a clear coat was applied, followed by the decal, followed by 2 more layers of clear coat.

Overall quite happy with the outcome! Could have done more sanding before applying paint to hide the layer lines better and the a matte coat I think would have worked better. Nonetheless the decal idea worked out well and I think it will be my goto - a big improvement over permanent markers.