I already have SEN66 and SFA30 in hands, which cover PM, RH/T, VOC, Nox, CO2, and HCHO. Do you think I should add more sensor (e.g. CO), if so, which one?
I am also considering SEN68 and SFA40, but they have not been released yet.
I planned to use ESP32-S3 as the MCU and build the project on a solderless breadboard. There will be a 3-inch display like the QingPing gen2 I have. I will 3d print the case, and likely it won’t be as small as Apollo AIR-1 to increase the expandability and reduce the difficulty of building it yourself.
The total cost is approximately $100-300. I will try to build it with only high-quality sensors, which is the whole point of starting this project (I am not completely satisfied with QingPing for the sensor quality and lack of HCHO and CO)
And of course, if the project is implemented successfully, I will make everything open source (3d printing STL, Arduino code, etc.)
Thanks for joining the forum. It’s very cool to hear about your project! Please keep us up-to-date with how everything goes!
This sounds like quite a solid sensor arrangement already. I haven’t seen many tests of the SEN66 since it’s so new, but the SEN55 performed well, so I’m sure this will also perform well. It’s definitely easier to use an all-in-one component like the SEN66 to decrease complexity.
From what I can tell, the SEN68 has an HCHO sensor included (in place of a CO2 sensor). Do you perhaps mean a SEN68 and something like an SCD40 instead? As long as power consumption is not a concern (I am assuming this will be USB-powered?), the SEN66 + SFA30/SFA40 sounds like a great choice, but either way, the stated accuracies look like they will be the same with either configuration.
I think that a CO sensor would also be a useful addition, and it’s always one of the most requested sensors on air quality monitors. Unfortunately, it’s quite hard to find a low-cost sensor that performs well and, to be honest, I haven’t been particularly impressed with any of the low-cost CO sensors that I’ve tried so far. Perhaps someone else has a suggestion in this regard. Are you currently looking at any CO sensors?
Based purely on specifications (because many of these sensors are still unreleased), the SEN68 + SCD43 looks to be a great combo. You get the same HCHO accuracy as the dedicated sensor, and you get better CO2 performance. The SCD43 actually looks to be very impressive based on the specifications.
As for the CO sensor, the SEN0132 (MQ7) appears to have several cross-sensitivities, and it also only has a detecting range of 20ppm - 2000ppm carbon monoxide. 20ppm is already enough to have health consequences (over longer periods).
The SEN0466 (electrochemical) looks to perform much better in both cross-sensitivities and detecting range. Of course, it is much more expensive, but I think this would definitely be the sensor to go for if you don’t mind the extra cost.
