Shinyei Model PPD42NS Particle Sensor

Hi,

I would like to get some input on using the Shinyei Model PPD42NS particle sensor.

Basically, its data is read by measuring the proportion of time a low pulse is sensed out of a 30 second window duration. An example sketch is here: http://www.seeedstudio.com/wiki/Grove_-_Dust_sensor

On my sensors (yes, tested several), I could find long periods of time (say 3 minutes) where my Arduino Uno doesn't even measure a single low pulse. Yes, I know, perhaps the there's really no dust particles to sense? I think not. Because, occasionally, the sensor does register an appreciable count that's nowhere near to zero.

Now, I've found that if I move the sensor, or if I gently encourage some air to flow through/around the sensor, the sensor does register an appreciable count too.

This gets me thinking. Is it necessary for some air flow to be encouraged through the sensor? I know there's already a heat resistor in it, and that's supposed to create some convection air flow. But somehow I get the sense that it's not causing enough flow for me.

If you've also worked with this particle sensor, I would greatly appreciate some input on using it! Thank you :)

zitseng: Hi,

I would like to get some input on using the Shinyei Model PPD42NS particle sensor.

Basically, its data is read by measuring the proportion of time a low pulse is sensed out of a 30 second window duration. An example sketch is here: http://www.seeedstudio.com/wiki/Grove_-_Dust_sensor

On my sensors (yes, tested several), I could find long periods of time (say 3 minutes) where my Arduino Uno doesn't even measure a single low pulse. Yes, I know, perhaps the there's really no dust particles to sense? I think not. Because, occasionally, the sensor does register an appreciable count that's nowhere near to zero.

Now, I've found that if I move the sensor, or if I gently encourage some air to flow through/around the sensor, the sensor does register an appreciable count too.

This gets me thinking. Is it necessary for some air flow to be encouraged through the sensor? I know there's already a heat resistor in it, and that's supposed to create some convection air flow. But somehow I get the sense that it's not causing enough flow for me.

If you've also worked with this particle sensor, I would greatly appreciate some input on using it! Thank you :)

The same issues :( described it in another topic, still looking for help... http://forum.arduino.cc/index.php?topic=155509.msg1328748#msg1328748

I have faced the same problem. If there is any one who can help us that will be great.

check this video : https://www.youtube.com/watch?v=v25owuUboxI can't remember exactly when but he shows that the sensor is a particule counter calibrated for a given air flow.

you'll see as well on other website that the ppd42ns has a resistor to create a convection air flow.

I just got my sensor and after checking it as is, I am planning to block the "front" openning , open one at the bottom and put a fan to accelerate the particule count.

Check this webpage as well : http://indiaairquality.com/2014/09/28/building-pickle-the-networked-pm2-5-monitor-part-1/

and actually most links from a google search on "ppd42ns arduino" have very informative informations.

... if you had some progress on your problem over the last months, please post them !!

links to datasheets of the sensor and code tried sofar are helpful to get things started ,

please post them...

A common problem with the PPD42NS and its cousins the DSM501 and the Sharp GP2Y1010 is that they give a bunch of zeros even when there are air particles.

I modified the sensor to add a fan and also increased the sensitivity by changing the threshold of the voltage. The modified PPD42NS is a lot more responsive. I have shared this information on my blog the day before yesterday (Dec 14).

http://indiaairquality.com/2014/12/14/measuring-the-pickle-jr-a-modified-ppd42-with-an-attached-fan/

Would love your comments!

A.J.

Hi aj8uppal !

I had seen your website during my searching around on the internet. Your posts are well written and very informative. Thanks a lot for taking the time to make those measurements, tests, tinkerings, etc. and writing them down ! It's being read and very usefull. (at least to 1 french reader over all the internet people ;))

On my side I've received my PPD42NS. I can confirm having a bunch of zero values. I have put in front a 5cm fan (but without any tubing ... just blowing towards the entry port) and I have closed the side window (the one that might let light enter the measurement area). I can confirm the zero count goes down even though not completely.

Once I have a fan properly mounted, the plan is to connect the arduino to a raspberry pi and let it record data for a while and make some graphs available "online". ... the downside : I don't have a PPD60PV-T2 or a Dylos to compare :/

As well as you I would rather not play with the 2 potentiometers ... but I need to find a way to calibrate my measurement.