@lukács-attila check wiring first, seems there are several sub version around thay may need other values from datasheet

@ambuj please see the begining of the discussion regarding MQ like reliability

@gohan I would have too much work going to 2.0 on every node I have, but I have to do this as a background task since I'll have to upgrade all my sketches first...

swapping hardware is an option, recabling everything is not my cup of tea

Hello,

I am trying to get my sensors back, and I have one that goes off the road several time...

board is a uno, with long antennae, mysensors lib is 1.5.

send: 3-3-0-0 s=255,c=0,t=17,pt=0,l=5,sg=0,st=fail:1.5.1
send: 3-3-0-0 s=255,c=0,t=17,pt=0,l=5,sg=0,st=fail:1.5.1

sometime resetting the uno button is enough, other not, and unpowering several times is the only way to make it work. BTW is is less than 1m from the controller.

sometimes, it goes well for 2h, then I have a 'fin parent' message on console and hten everything fail after.

any idea ?

@jumping see just above on power regressin curves, this is the result from a power regression based on the data sheet provided by one maker. Sometime I leave the data points in the sketch, sometime not (based on history

@jumping you will need to scale down the script obviously, in term of power it will be too short to have more than one.

@bezeefly said:

@epierre I obtained the following equation by polynomial fit the low ratio vs particle (pcs/283ml) graph in the DSM501 datasheet.

concentration = (0.1 * pow(ratio, 2)) + (619 * ratio) + 50;

Please help to check whether the equation is correct.

looks correct for the red curve

using http://www.xuru.org/rt/PR.asp with:
4 2500
8 5000
12 7500
16 10000
20 12500
22 15000
gives =7,613212955POWER(B3;2) + 467,3617082B3 + 631,9862425

a bit better

and on the previous one datasheet http://www.mouser.com/ds/2/744/Seeed_101020012-838657.pdf:
2 1000
3.9 2000
5.8 3000
7.2 4000
9 5000
10 6000
11.3 7000
12.6 8000
y = 19.09464953 x2 + 383.1041412 x + 174.9189116

@bezeefly said:

Samyoung DSM501A and Shinyei PPD42NS

This is formula for Shinyei, you're right, I'searched back but don't know if a formula was made out : https://groups.google.com/forum/#!topic/airqualityegg/A1F9padoW10

strangely here it is used too : http://learn.linksprite.com/arduino/shields/use-dust-sensor-dsm501-with-arduino/

a formula by Chris Nafis here: https://github.com/OSBSS/Samyoung_Dust_Sensor/blob/master/Samyoung_Dust_Sensor.ino

@AtmosCheme said:

I was going off of the SainSmart website that says the range for their module is 10 ppb to 200 ppm. That would cover 10 ppb to 200,000 ppb.

check their datasheet (or ask for it !)

The values keep dropping down as more and more ozone is added, I'm not thinking it is a problem with range as much as a problem with resolution. I have gone as high as around 50,000 ppb and continue to get response from the sensor.

yes it should be possible but you don't know from the datasheet the value. On a power regression you make an estimation with error, but that may change outside of know datapoints.

Ive thought of using mapping functions in my code as well as resolution functions. But I just wasn't sure if there was a component I could add to the circuit to improve resolution.

some as the Particle Photon has a better ADC that goes up to 4096

@AtmosCheme the datasheet gives the MQ131from 1 to 1000 ppb, so you reach the limit obviously

http://eph.ccs.miami.edu/precise/GasSensorSpecs/Ozone.pdf