Air Quality Sensor
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@Yveaux and there's worse : if you don't have the environment to calibrate it with real gas, it is just an indication... that is maybe why some projects that may have taken such sensor may hae a production process issue at the moment... In fact despite my researches, I've never found someone that said it made it to mesure correctly with gas sensors, mostly theory or just analog reading only...
An example: my MQ135 was silencious, I put its nose in the Aceton bottle:
Before:
Q2 :LPG :11ppm CO :0ppm SMOKE :18ppm
MQ6 :LPG :3ppm CH4 :36ppm
MQ131 :CL2 :2ppm O3 :3ppm
TGS2600:H2 :7602ppm C2H5OH:13706ppm C4H10 :26350ppm
MQ135 :CO2 :0ppm CO :0ppm CH3 :0ppm NH4 :0ppm
Dust :raw : 18 Voltage: 0.09 - Dust Density: -85.06After:
MQ2 :LPG :208ppm CO :0ppm SMOKE :832ppm
MQ6 :LPG :44ppm CH4 :172ppm
MQ131 :CL2 :16ppm O3 :17ppm
TGS2600:H2 :7774ppm C2H5OH:13818ppm C4H10 :27274ppm
MQ135 :CO2 :999ppm CO :0ppm CH3 :484ppm NH4 :1904ppm
Dust :raw : 58 Voltage: 0.28 - Dust Density: -51.86The MQ135 has reacted, but all others around...
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@Yveaux and there's worse : if you don't have the environment to calibrate it with real gas, it is just an indication... that is maybe why some projects that may have taken such sensor may hae a production process issue at the moment... In fact despite my researches, I've never found someone that said it made it to mesure correctly with gas sensors, mostly theory or just analog reading only...
An example: my MQ135 was silencious, I put its nose in the Aceton bottle:
Before:
Q2 :LPG :11ppm CO :0ppm SMOKE :18ppm
MQ6 :LPG :3ppm CH4 :36ppm
MQ131 :CL2 :2ppm O3 :3ppm
TGS2600:H2 :7602ppm C2H5OH:13706ppm C4H10 :26350ppm
MQ135 :CO2 :0ppm CO :0ppm CH3 :0ppm NH4 :0ppm
Dust :raw : 18 Voltage: 0.09 - Dust Density: -85.06After:
MQ2 :LPG :208ppm CO :0ppm SMOKE :832ppm
MQ6 :LPG :44ppm CH4 :172ppm
MQ131 :CL2 :16ppm O3 :17ppm
TGS2600:H2 :7774ppm C2H5OH:13818ppm C4H10 :27274ppm
MQ135 :CO2 :999ppm CO :0ppm CH3 :484ppm NH4 :1904ppm
Dust :raw : 58 Voltage: 0.28 - Dust Density: -51.86The MQ135 has reacted, but all others around...
doing the same on my basic sketch here what I have:
2014-08-03 11:29:57 3 0 1 24 -28393looks like my old sketch needs some update...
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Doing the same on the basic sketch :
Vrl / Rs / ratio:4.21 3731.17 0 CO ppm :infThen:
Vrl / Rs / ratio:4.21 3731.17 0 CO ppm :inf -
and now ethanol/isopropylène (bike chain cleaning product):
MQ2 :LPG :247ppm CO :0ppm SMOKE :1053ppm MQ6 :LPG :3527ppm CH4 :2160ppm MQ131 :CL2 :10ppm O3 :12ppm TGS2600:H2 :7891ppm C2H5OH:14279ppm C4H10 :27751ppm MQ135 :CO2 :0ppm CO :0ppm CH3 :0ppm NH4 :0ppm Dust :raw : 206 Voltage: 1.01 - Dust Density: 71.00 -
and now eveyone through aceton:
MQ2 :LPG :25ppm CO :0ppm SMOKE :48ppm MQ6 :LPG :19677ppm CH4 :3010ppm MQ131 :CL2 :71ppm O3 :51ppm TGS2600:H2 :8448ppm C2H5OH:15007ppm C4H10 :28738ppm MQ135 :CO2 :840ppm CO :0ppm CH3 :400ppm NH4 :1474ppm Dust :raw : 728 Voltage: 3.55 - Dust Density: 504.30remark that dust sensor goes up ! and TGS2600 goes down afterward:
MQ2 :LPG :8ppm CO :0ppm SMOKE :11ppm MQ6 :LPG :1264ppm CH4 :1194ppm MQ131 :CL2 :27ppm O3 :24ppm TGS2600:H2 :4966ppm C2H5OH:8407ppm C4H10 :16227ppm MQ135 :CO2 :840ppm CO :0ppm CH3 :400ppm NH4 :1474ppm Dust :raw : 165 Voltage: 0.81 - Dust Density: 36.96 -
@hek I now have the netatmo CO2 xml and json, they are based on the generic sensor.
But I don't have mysensors running on my vera...
I would need from you:
- the device and variable type
- an icon, but maybe I can reuse the other one
maybe
CO2 = {22, "urn:schemas-micasaverde-com:device:CO2Sensor:1", "D_CO2Sensor.xml", "CO2 "}
CO2 = {36, "urn:micasaverde-com:serviceId:CO2Sensor", "Concentration", "396" },S_CO2Sensor.json D_CO2Sensor.xml D_CO2Sensor.json
P.S. there's the icon from Nest plugin too: http://cocu.la/vera/nest/nest_co.png
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About initial calibration, just a warning from this graph:
you can see high levels around july 21 then dropping in august... the sensor has been restarted... that is what the call clean air...
this automatic reading at the start should be stored in the sketch and not reclaculated at each reboot or you would loose all reference on your data...
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@epierre did you just post the same reply 3 times or is the forum software showing yet another bug?
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I wanted to get acquainted with the MQ2 AirQuality Sensor so I took a look at the sketch from github.
One thing I noticed was that there is some sleep-time defined, is this just to make the sensor report the value every 30 seconds?
I guess it is not for saving power so you can run it on batteries because my understanding is that it needs to be hot in order to function correctly and that will drain the battery fast.Does not look like the calibration during setup takes in account the preheating time either, maybe it is a good idea to add a delay before the calibration so the sensor gets hot enough.
Please correct me if I'm wrong.
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@hek Here is a first list from the most commons:
- Carbon Monoxide – CO
- Carbon Dioxide – CO2
- Oxygen – O2
- Methane – CH4
- Hydrogen – H2
- Ammonia – NH3
- Isobutane – C4H10
- Ethanol – CH3CH2OH (aka C2H5OH or C2H60)
- Toluene – C6H5CH3
- Hydrogen Sulfide – H2S
- Nitrogen Dioxide – NO2
- Ozone – O3
- Hydrocarbons – VOC
- Chlorine CL2
- Ammonium NH4
- Ethanol CO2H50H
- Methyl CH3
- Acetone CH3_2CO
- LPG (both C3H8 C4H10)
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I wanted to get acquainted with the MQ2 AirQuality Sensor so I took a look at the sketch from github.
One thing I noticed was that there is some sleep-time defined, is this just to make the sensor report the value every 30 seconds?
I guess it is not for saving power so you can run it on batteries because my understanding is that it needs to be hot in order to function correctly and that will drain the battery fast.Does not look like the calibration during setup takes in account the preheating time either, maybe it is a good idea to add a delay before the calibration so the sensor gets hot enough.
Please correct me if I'm wrong.
@korttoma said:
Does not look like the calibration during setup takes in account the preheating time either, maybe it is a good idea to add a delay before the calibration so the sensor gets hot enough.
Please correct me if I'm wrong.
I see your point, but from experience I don't see a difference on heating... I should have a closer look. This one does not need a special pre-heating as some other (MQ-7).
Clearly this cannot run on battery on MQ/TGS/MICS series, so surely removing the sleep and adding a wait would do the trick the same way.
If you want to play and see something, the MQ135 is much better for it reacts to CO2, so having someone in a room or not you could see it easily changing.
A current weakness on the sketches is to take into accound humidity and temperature to correct the value, that will come too.
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I was looking for some other gas sensor, but these have no shield ready to connect to arduino :
Sensor Operating Voltage Heater Power MiCS-2710 (NO2) 2.5 V 43 mW MiCS-5525 (CO) 5.0 V 76 mWdo I need a dedicated 2.5 V linear regulator such as Microchip TC1071VCT713 ?
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@hek about initial calibration, how would I do check if there is a value in the eeprom or not, and if not run an initial calibration ?
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Hi,
First of al I'm a novice in all of this. I can read some code but the whole arduino thing is new to me.I tried to get the MQ135 working on my uno with tearing apart the : https://github.com/empierre/arduino/blob/master/1.3/MQ135dgi.ino.
I tried to pull out the bits and parts to get a accurate reading on my serial monitor.It sometimes read 1 or 2, but most of the time it is 0.
Can it have something to do with it being mounted on its own PCB? (I ordered the one suggested in the store..)
Can someone help me out?Groetjes Mark
