IKEA Vindriktning IAQ

I just came across this alternate PCB from LaskaKit, via some 3D models on Printables.

It has an ESP32, connectors for the Vindriktning's PM2.5 sensor and fan, as well as an onboard light sensor and more connectors, eg. for I2C. It also replaces the normal LEDs with WS2812's for a customized display (as seen in some of the 3D models mentioned above).

There seem to be a few issues with the USB connector and light sensor, but I haven't yet read through all of the discussions. 

It's currently (Aug. '22) only a little over 20€, which seems like a pretty good price to me, considering the parts cost, time it would take to assemble a custom PCB and even the possible issues. Especially since this would be a solution to the overly optimistic color thresholds of the Vindriktning I mentioned in Inspirations/references

For adding more IAQ sensors to my network, I'm now strongly considering building a sensor without Ikea parts, like this one.

Issues

• The PCB was a little too thick. Mine were 1.6mm nominally so better get 1.2mm.
• BME688 reads a temperature a few degrees above ambient. I was hoping the fan of the Vindriktning would cause enough air circulation to avoid this. I don't know if the sensor in the Vindriktning requires some heating like the SGP30 does and causes this or if it's just from all the electronics in such a small space.
• Sourcing SOT23-5 voltage regulators...
• Sourcing PicoBlade connectors. In the end the compatibles ones I ordered arrived also in time.
• CCS811 vs. SGP30: I was curious about the performance of both devices so I found this comparison. I think I also read somewhere else that the CCS811 should be more stable. However, my experience was the opposite, with the CCS811 constantly drifting. 
• The SGP30 seems to be very susceptible to humidity. After running the AC and opening a door or window the humidity increases and the TVOC/eCO2 values go through the roof. After a few minutes they seem to stabilize again.

Future improvements... maybe?

• Move BME688 to the outside or up against the perforated back wall of the sensor. Or just set a tempoffset in Tasmota.
• I wanted to modify the 3D printed mounts for the LED breakouts to be a mask showing the type of measurement, such that the LED light would project "CO2" or "VOC" in different colors through the Vindriktning front plate. Unfortunately, the writing would be too small for my printer, so maybe I'll have to order them somewhere or get a smaller nozzle.

This nicely shows the effect I was going for with the modified LED mounts.

When researching ways to go about modifying an IKEA Vindriktning I found these links quite helpful:

• Sören Beye's original mod on GitHub
• @lond's #IKEA Vindriktning PCB 
• Michi Lehr's build including a CCS811 sensor
• Blakadder's build with all the sensors, especially the tip to use the tasmota-allsensors build in order to not have to build a custom Tasmota version
• Usage of WS2812s with Tasmota
• List of Tasmota compatible sensors

Just now I came across @Catalin Sanda's #IKEA Vindriktning Daughterboard... if only I had found this sooner...

On the software side I used

• Tasmotizer to flash tasmota-allsensors (see above)
• and followed Jon Oxer's instructions on setting up MQTT, NodeRed, InfluxDB and Grafana

I read somewhere that Apparently the Vindriktnings color thresholds are a bit optimistic so I tried to find more reliable ones for PM2.5, VOC and CO2 but I'm not very happy with the results:

• PM2.5: https://blissair.com/what-is-pm-2-5.htm 
• PM2.5: https://en.wikipedia.org/wiki/Air_quality_index#CAQI
• VOC, CO2: https://cdn.hornbach.de/data/shop/D04/001/780/491/871/060/10176848_Doc_03_DE_20201103134757.pdf
• CO2: https://www.breeze-technologies.de/blog/calculating-an-actionable-indoor-air-quality-index/

If you have a good source, please leave a comment.

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Edit 2022-06-22: Added link about Vindriktning color thresholds.

Edit 2022-08-29: Just came across this thread on home-assistant.io with a list of even more builds.