I just discovered that .25" shrink tube fits the inlet nipple of the SDS011. Prior to this i used a .25" ID automotive tubing, which had a thick wall and which I had to wedge in against the circuit board. And so it fell off.
the .25" shrinkfit works perfectly, even without heating. Now to find a cheap 90degree angle that is .25" OD.
Remember that the SDS spec sheet calls for [gravity] fan side down. Remember that the spec allows a fairly long tube but they suggest black, which absorbs light. I have not exceeded 10cm tubing length.
that’s probably preferred to shrink tube. can you get 90 degree elbows? thing is, SDS factory instructions say mount fan down, horizontally. The tube should be black to reduce light but - probably doesn’t matter.
I have built about 34 of these, maybe 15 enclosures of this type which have the schnauz (nose). I think it is important to separate inlet and discharge. This has a course inlet filte on the PVC, and a fine filter on the tube. Purple air has them within 1cm. Probably in the end doesn’t make much difference on this grade of equipment. I have upgraded all of the sytems to BME280 - but most are on a bench now and i need to distribute them.
The other thing i read was that the fan on sds goes down (read instructions - gravity down). I think this is to keep particles moving through the chamber thus increasing the life (average 3 years) of the SDS.
The SDS is a venerable sensor. It’s used widely in commercial equipment. The Plantronics PM2.5 family has a minute air flow capacity, tiny laser chamber, and no inlet hose capability. Perhaps the small fan size dictates not allowing external tubing.
Cool enclosure!
I have built about 30 sensors with the sds011 and the bme280. The sds’s still work, but I had a few nodemcu ‘s that failed after some time.
At the moment I only build combineert meters with the noise meter.I just started using the sensirion.
I am also soldering my own microphones. That’s quite a challenge.
what do you need to add to airRohr to sense sound? I don’t know if their mapping system even handles sound. Would you consider selling mic assemblies? Also, what continent are you on? I am in California.
For the sound meter you need to check out the github from hbitter. You need a Teensy 4.0 and the usual NodeMCU 3.0. I live in the Netherlands in Europe.
I might consider selling mems microphones as soon as I am more skilled at making them. Helmut Bitter , the German developer of the sound meter will be very pleased if his meter will be used in the USA as well. I have email contact with him and have received some microphones to test from him.
This is the link where my sensors are at. https://maps.sensor.community/?nowind#16/52.1003/5.1159
impressive! i am overwhelmed with other projects right now. interestested in doing sound next year sometime. i still have parts for ten airRohr that i should finish assembling.
would be good to have a regimen for testing and calibrating. one of the products offered sensors that could be removed with a simple click, and sent in for factory recalibration. - dave
As a matter of fact I do have ways to calibrate my meters. I have several friends who are sound experts. And the RIVM, a Dutch government institute that does a lot of things, including sound measuring, is going to test two of my meters.
A couple of months ago one of my meters has been tested in a sound lab. I have the official test report and the sensor community meter came out very good.
