Forum Sensor.Community

What sensors can be used?

You suggest to use the BME280 and SDS011.

Is it possible (or will it be) to use also a way cheaper (and similar good measurs) GP2Y10 for dust or a DHT22 for Temp/Humidity?

We had the best long term experience with those sensors (BME280 and SDS011). In an old version of the kit we used the DHT22. But after a short while it always showed 99% humidity all the time.

You can find a list of sensors supported by our firmware. The DHT22 is supported, but not recommended. If you want to use the GP2Y10, then you have to create your firmware by forking ours.

Sharp GP2Y10 use infrared LED instead of a laser. This sensor is in fact cheaper, but also less precise. NovaFitness SDS011 isn’t the best dust sensor on market, but it’s a very good compromise between price and measuring capabilities.

There is other cheap infrared based solution that is supported by current Sensor.Community firmware: Shinyei PPD42.

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Hi.
I am preparing a measuring station in my location (Asturias-Spain), I only have to receive the SDS011 sensor and connect, because I already have nodeMCU v3 working in tests with the BME280 sensor.
I am also planning to buy another unit and I wanted to ask you about the Sensirion SPS32 sensor, which according to technical characteristics has better precision than the SDS011, what do you think? Is the connection and firmware similar to how it is done with the sensor SDS011 in the kit1 tutorial (Sensor Community)?
Greetings and thanks for your response.

Yes, SPS30 (not SPS32 which does not exist… yet?) is supported by firmware. It is more precise then SDS011. You can use it for sure! Connection schematics is here:

Regarding SPS30 vs SDS011 there is little difference for PM2.5 as long as humidity is not extremely high. In those cases, the SDS011 reports higher levels. The SPS030 output is smoother. At least this is my experience with my setup.

Both sensors are located next to each other.

And as I was not allowed to show two plots… here is the same period for PM10. The SPS30’s PM10 is virtually identical with the PM2.5 output.

Yes. SPS30 should be treated as very good mCert Certified PM2.5 sensor. And it works nice up to 80% RH which is no small feat.

However SDS011 is still a very nice sensor. You need to have a couple things in mind:

  • It requires voltage above 4.75V (below this measured values will be significantly lower than actual).
  • Relative humidity above 70% is no go for this sensor. Measured values will be way higher. You may compensate this in software using hand crafted algorithms, but keep in mind that high RH% may also shorten lifespan of sensor due to internal water vapor condensation. Electronics and water usually don’t mix very well.
  • Using SDS011 below -10C is not recommended. We got many reports that measured values are significantly lower than actual values. For now it’s not clear if it’s connected with fan performance or laser diode low temperature wavelength drift (band gap change). My climate chamber doesn’t got that low to make a proper test.

I live in Poland. Our weather conditions are far from perfect for SDS011. At least 5 months in year we got constant RH>70%. Sometimes in winter outdoor temperature drops below -20C. Just take a look at last week:

That’s why in December 2018 to address those 3 problems (supply voltage, RH% and low temperatures) we started development of NAM 0.3. NAM units are equipped with PTC heating element controlled by HECA board (SHT30+mosfet). Unit shown on graphs above has PTC heater enabled 24/7. So this is maximal performance of this design (usually HECA turns off heating below 60%RH or above 5C). Warm air is directed to SDS011, than via SDS’s fan exhaust to the enclosure with electronics. Thanks to this SDS011 works in it’s designed temperature specs. Both internally in measurement chamber and outside due to design of NAM enclosure.

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This is really interesting - thanks for sharing! I wasn’t aware of this but seriously consider getting one of these kits, too. Do you by change have tried the Tera NextPM sensor which also has internal heating? Funny to see that the price of the 0.3.3 kit is similar to the NextPM sensor.

I have succeeded about one year ago to make the NextPM work on the beta version of the firmware (and on an ESP32) but now my code derivated to much from the current master and I am quite bored of getting no feedback from Tera which I was in contact with (the guy contacted me first, sent me a sensor, ask me to adapt the code and after a while he stopped to answer my mails. I think SC is not bankable enough…). Someone tried to make it work again a few months ago though: Next PM Sensor enablement · Issue #794 · opendata-stuttgart/sensors-software · GitHub
I still have the doc but I miss the motivation. I someone succeed to change my mind I can help and explain my code.

The “someone”… that’s me :slight_smile: Greetings!

The short times the NextPM worked I did not see a significant improvement in high humidity. The results were close to the other sensors with no heating. Hence the NextPM will sit in the shelf until something happens.

Oh, and I just ordered the NAM 0.3.3 kit.

:slight_smile: There is a function to monitor if the heater started (a kind of 8 bytes code). I think I found my old working codes again. We could continue if other people want it. But in that case we have to communicate thu a direct system (EMail, Whatsapp, Jitsi or something).

Just want to say thank you for your enthusiasm in developing NAM.

Are you planing to update NAM 0.3 soldering instructions with english versions?
I was wondering (I’m a DIY newbie) is it possible to add a H2S sensor to NAM 0.3?

Yes. I’m working on it as we speak.

Everything is possible. But I’m not familiar with that sensor (yet).

NB! Sensor.community currently does not support air heated sensors (NAM and similar). It is not a big deal to add support for hardware. But the problem is how to distinguish sensors with heaters from other sensors of the same type. We need some additional metadata for that.

Basically, we need the following data:

  1. SHT30 sensor’s data (both temperature and humidity) - to see the inlet temperature.
  2. External temperature and humidity data - to monitor external temperature
  3. PM sensor data with a mark that this is sensor with heater.
  4. heater trigger value to see when heater is ON or OFF

I don’t want to be rude… But I’ve been hearing “the metadata” phrase for 2 years now… Yet we continue to send data to Sensor.Commumity. We are still waiting for specification what should we implement to make S.C. happy.

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Lets discuss metadata problem internally as here it will be offtopic…

Hi I would be grateful if you could share your sources of information you have that says that the SPS30 is more precise than the SDS011 please. I am interested as we have both but looking at the SPS30 information sheet the operational temperature range is not so good as the SDS011. Or perhaps I am mistaken?

I’ve been running the default setup SDS011+BME280 for awhile now and the BME280 is pretty accurate but the PM10 of the SDS011 is sometimes way off. Because of this and the comment that the SPS30 is more accurate I bought a SPS30 and created a second node with SHT35 and SPS30. The SHT35 is way off (could be the casing) and SPS30 shows a lot of times the same values for PM1 to PM10 while it’s almost sitting outside the cage. The same issue for SPS30 is described in SPS30 PM10 no difference to PM2.5 · Issue #673 · opendata-stuttgart/sensors-software · GitHub

Where do I find the mearurements of the sps30 on the map?
I only saw PM2.5 and PM10
Wim