We actually have a sample of the Bosch in our office but haven’t come along to test it yet. Maybe with this call, I will get our team onto it.
The form factor has pros and cons in my opinion. The size and lower energy consumption definitely opens new applications but the problem is that it needs a clear field of view to do the measurements.
This could in turn restrict the applicability, eg as a wearable sensor.
In general I think it’s great to see innovations in the PM sensor field but often minimizations go on costs of accuracy.
We saw that for example with the Sensirion photo acoustic CO2 SCD4x sensor that is tiny but needs more black box algorithms to compensate for certain environmental conditions that then limits the range of applications.
> Laser light is emitted from the sensor and focused by the sensor lens at approximately 5 mm from the top of the sensor’s lens surface.
> Particles traveling in free space due to the natural ambient airflow are detected when passing through the laser focal (sensitive) region.
> Due to the interaction between particles and light, the light scatters in different directions; a fraction is back-scattered towards the sensor, where the integrated photo-detectors detect it.
> The back-scattered signal is processed by unique algorithms (based on particle counts, particle relative velocity, probed air volume during measurement) to derive the particulate matter mass concentration.
Curious if there are any maintenance requirements for the bosch sensor.
How does this model deal with this?
You can detrend for high humidities, but once water condenses, the only way round this would be to add a drying instrument.
It's that fog is being detected as a particle. This distorts the measured values.
This is great for flexibility but very impractical especially for DIY space. Hopefully small fully integrated modules on something like edgeconnector PCB come out soon enough.
Sparkfun sell a module with a ground plane + thermal pad as heat sink. This is suggested as OK by Bosch, though adding a small heatsink is probably a good idea, or just mount the enclosure on a metal surface.
https://www.sparkfun.com/sparkfun-air-quality-pm1-pm2-5-pm10...
https://www.bosch-sensortec.com/media/boschsensortec/downloa...
arnejenssen•4h ago
mjs•3h ago
progbits•1h ago
Cost is one, but this isn't something you can measure quickly on demand, you want to keep averaging multiple measurements over time. So unless you want to hold out your phone for minutes to get a measurement it doesn't seem practical.