Cheap particle counter for clean bench. Is it good enough? - Page 1
Forum section: electronics / general

author: masterpj55
author_rank: Contributor
timestamp: March 14, 2021, 10:11:00 pm
content: There are 2 particle counters I found which are cheap which is the- Ebay chinese handheld particle counter for 169 USD delivered (without import taxes)https://www.ebay.com/itm/Handheld-Particle-Counter-PM2-5-PM10-Air-Quality-Detector-USB-Port-Air-Tester/143884576751?hash=item21803067ef:g:pz0AAOSwr15f1OcU- the Dylos DC1100 which is 220 USD delivered (without import taxes)https://www.ebay.com/itm/Dylos-DC1100-Standard-Laser-Air-Quality-Monitor-With-AC-Adaptor-and-Manual-NEW/401682138600?epid=3024666334&hash=item5d861f05e8:g:muoAAOSwoTlgQoH5What niche do these particle counters fill? Would either of these particle counters be able to suffice for measuring the particle count in a clean bench (laminar flood hood) to see if it's still adequate and the filters are in need of replacement or not?Very interested in hearing peoples opinions on them and if they are usefull at all for the application or where their application and limit lies.Use for my clean bench is handling some semiconductors (exposed) and working on optics so this is why I have been considering to verify the quality of older (used) clean benches.

author: ace1903
author_rank: Regular Contributor
timestamp: March 15, 2021, 01:27:20 pm
content: I am guessing that you made that youtube series with a fume hood for dealing HF.Great content, Thanks!I haven't experience with those two units but I have the cheapest unit from aliexpress ~50$. I think that most of them are based on the same sensor(clone of some Sharp sensor).During winter here is extremely polluted (Skopje is in the top 10 cities in the world by pollution regularly) and I am using my unit to verify that the air purifier does its job.I am satisfied that I can observe pollution by pm2.5 and pm10 and take corrective actions with the air purifier.One point that is important to note that my units measure correctly in still air. I am not sure that you will use it in still air or laminar flow?Also not sure how you can relate the quality of the bench with the number of particles? Maybe you want to check the effectiveness of the inbuilt HEPA filter?Sure I haven't helped with my comment but wanted just to say thanks for your educational videos.

author: thm_w
author_rank: Super Contributor
timestamp: March 15, 2021, 08:25:09 pm
content: Those might be overkill.Sharp sensor (LED based) is not very good. Laser based sensors are <$30 and work very well. You will find them inside various high end air filters (Dyson, xiaomi, etc.).Cheapest way is to buy SDS011 or similar and hook it up to your PC, monitor it manually.More convenient would be a portable style unit like this:https://www.aliexpress.com/item/4000890026809.htmlI think you can test your system by lighting a match, let it smoulder, and monitor the particle count.

author: masterpj55
author_rank: Contributor
timestamp: March 15, 2021, 11:43:05 pm
content: Quote from: ace1903 on March 15, 2021, 01:27:20 pmNo that wasn't me.I would love a cheaper option then the ones I linked since it really only serves me one application being that one.The handheld ones are most certainy said to be laser source based.I absolutely love your advice of the SDS011.. great price and for sure acceptible to use a pc or single board computer or arduino etc to measure as I didn't feel like spending the prices for the handheld one! Thank you!!

author: DrG
author_rank: Super Contributor
timestamp: March 16, 2021, 12:25:16 am
content: Quote from: masterpj55 on March 14, 2021, 10:11:00 pmI have a Panasonic SN-GCJA5 Particulate Matter Laser Sensor. I interfaced it to a Teensy 4.0 and a 1.8" TFT. I also added a visual and auditory alarm. Some day I may even put it in an enclosure.It has a readout in counts x size and density and also a check on the laser diode, photo diode and fan (see the screens). It seems to work well enough and if you put it near burned match smoke (or a solder iron fume trail), it most certainly shows huge increases, as expected.Very interested in hearing peoples opinions on them and if they are usefull at all for the application or where their application and limit lies.Here in lies the "rub"; I have no standard to validate the measures. I can't understate the importance of that aspect with regard to potential utility. It behaves as I would, in general, expect, but that is very different than validating the measures.This has come up in a thread before. It was suggested to compare them to a nearby "official" stations that track PM. I like that suggestion, if you can manage it easily.It may be possible to find some lab that has high end equipment and maybe some standard aerosols with certain PM concentrations (they must exist somewhere, but I have never seen them for sale) and use them to do some calibrations and testing.I like this Panasonic (I also have a Honeywell here) and especially the status check on the micro fan. I would think that this is an important part of the system and they talk about a compensation mode in the datasheets. Of course, these things are not explained as well as I would like.Hope it helps.

author: masterpj55
author_rank: Contributor
timestamp: March 16, 2021, 12:50:49 am
content: it looks great! i bought the particle laser sensor listed above through amazon (should arrive in 2 days) which i can interface with a pc.The only thing I struggle to find out is a good set of reference how particle size corrilates to cleanlyness.. say in a clean box of clean bench what is a good number (to for example know if your filters need changing).Say for laser optical work or some rough semiconductor or open hard drive work as reference!I noticed your display also shows PM1.0 this is something that isn't to be found on the other laser particle counter (says PM10 and 2.5). is this an advantage of the sensor you bought?

author: DrG
author_rank: Super Contributor
timestamp: March 16, 2021, 03:29:58 pm
content: Quote from: masterpj55 on March 16, 2021, 12:50:49 amThanks, but I was aiming at indoor air quality. For example, I am alerting based on USEPA 24h limits.Code:// Levels for alarm based on EPA 24h limitsunsigned long PM2_5alarm = 35.0;unsigned long PM10_0alarm = 150.0;I don't know squat about clean rooms and the like but a quick search looks like there are all sorts of "standards" e.g.,https://www.americancleanrooms.com/cleanroom-classifications/. I have no idea how suitable your device will be for such purposes (again the validation issue previously mentioned).Edited to add: as for the 1.0 um - well, yeah, I like that, but it may be included in other sensors. You have to look at the datasheet. For example, it should say something about "smallest particle size detected" or something similar. It is then "assumed" that a measure reporting, for example, <2.5 um is including the smallest size particles the sensor can measure.BUT, and I know I keep coming back to this, I have no way of validating or calibrating these sensors. I am basically basing whatever utility mine has (and it is more experimental interest than anything very important) on the data sheet and gross empirical observation (like the measures in response to some smoke that I mentioned earlier).These are very important questions and I would be very concerned to find the answers, if the application is also very important - you know what I mean?

author: David Hess
author_rank: Super Contributor
timestamp: March 16, 2021, 04:47:48 pm
content: Quote from: masterpj55 on March 14, 2021, 10:11:00 pmI would use them to verify that a laminar flow bench is operating correctly.

author: GodIsRealUnless DefinedInt
author_rank: Contributor
timestamp: March 16, 2021, 11:54:07 pm
content: I've seen laser light scattering sensors on Ali for about $14 Inc shipping. Usually these styles of units bin data into size categories <1um, to 10um and in between. How much worth they are depends on your filters and their specification. Usually HEPAs run around 0.3um. So it would be pushing it with a unit like I've seen. Question I would have is what does <1um mean, where does the particle size limit get reached for deflection against a sensor. These deflection sensor based units also have a shelf life so consider them consumables. I would use them for sure in a home setting or in a garage workshop. They'll definitely spike when you fire up a soldering iron and vaporize solder/Flux. But for a commercial operation you'd want something certified as to performance specifications.Edit: sensor only intended to hook up over serial to get the data.Data is in per deciliter or cubic meter so with most scientific gear you have to convert yourself to local units.

author: masterpj55
author_rank: Contributor
timestamp: March 17, 2021, 02:10:11 am
content: Quote from: David Hess on March 16, 2021, 04:47:48 pmExactly what I bought mine for !However is the SDS011 sufficient for that you think?