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  3. Air Quality Sensor

Air Quality Sensor

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calibrationaqigas sensorhchoair quality
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  • epierreE epierre

    @alexsh1 said:

    Also how do you connect it if it comes on the board like this?
    http://i.ebayimg.com/00/s/NjAwWDYwMA==/z/vMIAAOxycD9TTOVW/$_1.JPG

    easy here, the AOUT is the one you will put on an analog one.

    the DOUT (Digital OUT) is just an alarm linked to a level you could change on the board)

    alexsh1A Offline
    alexsh1A Offline
    alexsh1
    wrote on last edited by
    #223

    @epierre said:

    the DOUT (Digital OUT) is just an alarm linked to a level you could change on the board)

    So DOUT is not used. Just AOUT?

    epierreE 1 Reply Last reply
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    • alexsh1A alexsh1

      @epierre said:

      the DOUT (Digital OUT) is just an alarm linked to a level you could change on the board)

      So DOUT is not used. Just AOUT?

      epierreE Offline
      epierreE Offline
      epierre
      Hero Member
      wrote on last edited by
      #224

      @alexsh1 said:

      @epierre said:

      the DOUT (Digital OUT) is just an alarm linked to a level you could change on the board)

      So DOUT is not used. Just AOUT?

      yes !

      z-wave - Vera -> Domoticz
      rfx - Domoticz <- MyDomoAtHome <- Imperihome
      mysensors -> mysensors-gw -> Domoticz

      1 Reply Last reply
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      • alexsh1A Offline
        alexsh1A Offline
        alexsh1
        wrote on last edited by alexsh1
        #225

        @epierre For the air quality purpose which sensor would you recommend TSG-2600 or TS2602? They are slightly different, but both detect aiir contaminants (based on ppm of H2 and EtOH).

        So far, I got MH-Z14A and the Dust sensor working with OLED screen and Domoticz and I just want to add 1-2 sensors to finish the project.

        1 Reply Last reply
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        • epierreE Offline
          epierreE Offline
          epierre
          Hero Member
          wrote on last edited by
          #226

          @alexsh1 well any I would think for they are similar technology

          z-wave - Vera -> Domoticz
          rfx - Domoticz <- MyDomoAtHome <- Imperihome
          mysensors -> mysensors-gw -> Domoticz

          alexsh1A 1 Reply Last reply
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          • epierreE epierre

            @alexsh1 well any I would think for they are similar technology

            alexsh1A Offline
            alexsh1A Offline
            alexsh1
            wrote on last edited by
            #227

            @epierre What about MICS-4514 or MICS-5524?

            I am thinking ordering this board:
            https://sgx.cdistore.com/ProductDetail/MICSVZ86F-SGX-Sensortech-Limited-formerly-e2v/556306/#.V2Bw7jVUmec

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            • Tore André RosanderT Offline
              Tore André RosanderT Offline
              Tore André Rosander
              wrote on last edited by Tore André Rosander
              #228

              How do i get the Airquality sensor to show in domoticz? I use the AirQuality example from the library and MQ2.
              I can see that it works in the serial, and it shows as a node under the mysensors hardware, but nothing in log or the device list when i expose it for gas.

              0_1466081228162_upload-0f9ebe47-10d5-446c-a3bd-24c1649c94c1

              epierreE 1 Reply Last reply
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              • Tore André RosanderT Tore André Rosander

                How do i get the Airquality sensor to show in domoticz? I use the AirQuality example from the library and MQ2.
                I can see that it works in the serial, and it shows as a node under the mysensors hardware, but nothing in log or the device list when i expose it for gas.

                0_1466081228162_upload-0f9ebe47-10d5-446c-a3bd-24c1649c94c1

                epierreE Offline
                epierreE Offline
                epierre
                Hero Member
                wrote on last edited by
                #229

                @Tore-André-Rosander said:

                ut nothing in log or the device list when i expose it for gas.

                huh you're on which version of mysensors ? have you tried the console (in arduino programmer) to see if there are some readings or a good wiring ?

                z-wave - Vera -> Domoticz
                rfx - Domoticz <- MyDomoAtHome <- Imperihome
                mysensors -> mysensors-gw -> Domoticz

                1 Reply Last reply
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                • Tore André RosanderT Offline
                  Tore André RosanderT Offline
                  Tore André Rosander
                  wrote on last edited by Tore André Rosander
                  #230

                  @epierre Hi! The dev branch (v 2) and the raspberry pi gateway (nrf24 directly connected to RPi GPIO). This is what i get in the serial console when i test with gas from a lighter:

                  Starting sensor (RNNNA-, 2.0.0-beta)
                  Radio init successful.
                  find parent
                  send: 255-255-255-255 s=255,c=3,t=7,pt=0,l=0,sg=0,st=bc:
                  find parent
                  send: 255-255-255-255 s=255,c=3,t=7,pt=0,l=0,sg=0,st=bc:
                  read: 0-0-255 s=255,c=3,t=8,pt=1,l=1,sg=0:0
                  parent=0, d=1
                  req id
                  send: 255-255-0-0 s=255,c=3,t=3,pt=0,l=0,sg=0,st=ok:
                  req id
                  send: 255-255-0-0 s=255,c=3,t=3,pt=0,l=0,sg=0,st=ok:
                  read: 0-0-255 s=255,c=3,t=4,pt=0,l=2,sg=0:5
                  
                  send: 5-5-0-0 s=255,c=3,t=15,pt=0,l=2,sg=0,st=ok:
                  send: 5-5-0-0 s=255,c=0,t=17,pt=0,l=10,sg=0,st=ok:2.0.0-beta
                  send: 5-5-0-0 s=255,c=3,t=6,pt=1,l=1,sg=0,st=fail:0
                  id=5
                  Init complete, id=5, parent=0, distance=1
                  0
                  LPG:0ppm    CO:0ppm    SMOKE:0ppm
                  0
                  LPG:8ppm    CO:47ppm    SMOKE:18ppm
                  send: 5-5-0-0 s=0,c=1,t=37,pt=2,l=2,sg=0,st=ok:95
                  0
                  LPG:0ppm    CO:0ppm    SMOKE:0ppm
                  send: 5-5-0-0 s=0,c=1,t=37,pt=2,l=2,sg=0,st=ok:0```
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                  • epierreE Offline
                    epierreE Offline
                    epierre
                    Hero Member
                    wrote on last edited by
                    #231

                    @Tore-André-Rosander said:

                    t=37

                    I don't know, would it be possible to have someone knowing the difference of the gateway with domoticz for 2.0 ? here it seems correct to me, some value are well seend from the sensor, so it is between the gateway and domoticz for me.

                    z-wave - Vera -> Domoticz
                    rfx - Domoticz <- MyDomoAtHome <- Imperihome
                    mysensors -> mysensors-gw -> Domoticz

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                    • tuimansoT Offline
                      tuimansoT Offline
                      tuimanso
                      wrote on last edited by
                      #232

                      @epierre I am attempting to apply this code to work with the MQ-8. I am trying to get rid of all of the radio and gw stuff that is in the code. Do you have anything that just calibrates the sensor and reads out the value without of all these other libraries?

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                      • tuimansoT Offline
                        tuimansoT Offline
                        tuimanso
                        wrote on last edited by
                        #233

                        @epierre Also, what is the purpose of #define MQ135_MAXRSRO 2.428 //for CO2
                        #define MQ135_MINRSRO? I don't see them being referenced after they're defined?

                        epierreE 1 Reply Last reply
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                        • tuimansoT tuimanso

                          @epierre Also, what is the purpose of #define MQ135_MAXRSRO 2.428 //for CO2
                          #define MQ135_MINRSRO? I don't see them being referenced after they're defined?

                          epierreE Offline
                          epierreE Offline
                          epierre
                          Hero Member
                          wrote on last edited by
                          #234

                          @tuimanso said:

                          @epierre Also, what is the purpose of #define MQ135_MAXRSRO 2.428 //for CO2
                          #define MQ135_MINRSRO? I don't see them being referenced after they're defined?

                          Datasheet defines min and max values they should guarantee, this is an application of it.

                          if(validinterval<MQ135_MAXRSRO && validinterval>MQ135_MINRSRO) {
                          

                          z-wave - Vera -&gt; Domoticz
                          rfx - Domoticz &lt;- MyDomoAtHome &lt;- Imperihome
                          mysensors -&gt; mysensors-gw -&gt; Domoticz

                          1 Reply Last reply
                          0
                          • tuimansoT Offline
                            tuimansoT Offline
                            tuimanso
                            wrote on last edited by
                            #235

                            Your previous message

                            Hello,

                            I have a question about the MQ-8 sensor module . The potentiometer that is soldered onto the board, is it to control the sensitivity of the LED light or for the sensor itself? According to the datasheet for the sensor, the RL (load resistance) for the sensor should be at minimum 10k Ohm, yet I only see an SMD 102 resistor on the board, which is a 1K Ohm resistor. I have used a multimeter to connect the 5V pin and the AOUT pin, and I get precisely a measurement of about 1K Ohm... Does that mean that I should connect a load resistor to this?

                            This value seems very important since it is referenced in the code, the RL is part of the calculations, yet it is already pre-written 10K ohms...

                            Please Clarify
                            Thanks

                            ysinhY 1 Reply Last reply
                            0
                            • AtmosChemeA Offline
                              AtmosChemeA Offline
                              AtmosCheme
                              wrote on last edited by
                              #236

                              Hello everyone,

                              I have a few of these sensors, but lately I have been concentrating on a MQ131 ozone sensor module from SainSmart. I am building an array utilizing MQ gas sensors and an Arduino that can be attached to a drone to measure vertical concnentration profiles of ground level ozone.

                              I am using an ozone generator and a 2B Technologies Ozone Monitor for the calibration of the sensor.

                              I have done the 24 hour burn in period on my sensors.
                              I have warmed them up to get steady values on my serial monitor.

                              The problem that I am having is that I am creating nearly 20,000 ppb O3 and the analog output is only around 25 to 30 units. It works out to around 922 ppb per unit.

                              Example before ozone is added the sensor reading is steady at 41. After raising the concentration of O3 to 18,727.5 ppb the reading drops to around 17-18.

                              Recently I have added a 22,000 ohm resistor in series with the analog output so that my readings start out at 971. But I am still only dropping around 20 units to 951 when ozone levels rise to nearly 20,000 ppb.

                              My question is how do I use a larger range of the units. There are 1023 possible values and I would like to see my reading drop from 971 to maybe the 200 area so that I am using more of the range. I would like each unit to be worth about 0.5 ppb. Ambient outdoor concentrations very rarely go higher than maybe 150 ppb so with the setup I have that would not even register on the serial output.

                              Thank you in advance for any help.

                              epierreE 1 Reply Last reply
                              1
                              • AtmosChemeA AtmosCheme

                                Hello everyone,

                                I have a few of these sensors, but lately I have been concentrating on a MQ131 ozone sensor module from SainSmart. I am building an array utilizing MQ gas sensors and an Arduino that can be attached to a drone to measure vertical concnentration profiles of ground level ozone.

                                I am using an ozone generator and a 2B Technologies Ozone Monitor for the calibration of the sensor.

                                I have done the 24 hour burn in period on my sensors.
                                I have warmed them up to get steady values on my serial monitor.

                                The problem that I am having is that I am creating nearly 20,000 ppb O3 and the analog output is only around 25 to 30 units. It works out to around 922 ppb per unit.

                                Example before ozone is added the sensor reading is steady at 41. After raising the concentration of O3 to 18,727.5 ppb the reading drops to around 17-18.

                                Recently I have added a 22,000 ohm resistor in series with the analog output so that my readings start out at 971. But I am still only dropping around 20 units to 951 when ozone levels rise to nearly 20,000 ppb.

                                My question is how do I use a larger range of the units. There are 1023 possible values and I would like to see my reading drop from 971 to maybe the 200 area so that I am using more of the range. I would like each unit to be worth about 0.5 ppb. Ambient outdoor concentrations very rarely go higher than maybe 150 ppb so with the setup I have that would not even register on the serial output.

                                Thank you in advance for any help.

                                epierreE Offline
                                epierreE Offline
                                epierre
                                Hero Member
                                wrote on last edited by
                                #237

                                @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

                                z-wave - Vera -&gt; Domoticz
                                rfx - Domoticz &lt;- MyDomoAtHome &lt;- Imperihome
                                mysensors -&gt; mysensors-gw -&gt; Domoticz

                                AtmosChemeA 1 Reply Last reply
                                0
                                • epierreE epierre

                                  @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

                                  AtmosChemeA Offline
                                  AtmosChemeA Offline
                                  AtmosCheme
                                  wrote on last edited by
                                  #238

                                  @epierre

                                  Thank you for the reply epierre.

                                  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.

                                  http://www.sainsmart.com/sensors/eco/sainsmart-mq131-gas-sensor-ozone-module-for-arduino-uno-mega2560-r3-raspberry-pi.html

                                  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.

                                  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.

                                  In my latest sketch I have used a calibration code that analog reads the sensor for 6 minutes, and then remaps the min and max values observed during that time. I though this would get a broader range of values. The problem is that the longer the sensor is on it becomes stable so the min and max values become the same and there is nothing to map. So the longer it runs the smaller the range of values in the serial monitor.

                                  epierreE 1 Reply Last reply
                                  0
                                  • AtmosChemeA AtmosCheme

                                    @epierre

                                    Thank you for the reply epierre.

                                    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.

                                    http://www.sainsmart.com/sensors/eco/sainsmart-mq131-gas-sensor-ozone-module-for-arduino-uno-mega2560-r3-raspberry-pi.html

                                    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.

                                    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.

                                    In my latest sketch I have used a calibration code that analog reads the sensor for 6 minutes, and then remaps the min and max values observed during that time. I though this would get a broader range of values. The problem is that the longer the sensor is on it becomes stable so the min and max values become the same and there is nothing to map. So the longer it runs the smaller the range of values in the serial monitor.

                                    epierreE Offline
                                    epierreE Offline
                                    epierre
                                    Hero Member
                                    wrote on last edited by
                                    #239

                                    @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

                                    z-wave - Vera -&gt; Domoticz
                                    rfx - Domoticz &lt;- MyDomoAtHome &lt;- Imperihome
                                    mysensors -&gt; mysensors-gw -&gt; Domoticz

                                    1 Reply Last reply
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                                    • jnewton957J Offline
                                      jnewton957J Offline
                                      jnewton957
                                      wrote on last edited by
                                      #240

                                      Hi,

                                      I just try to connect 7 sensors to an nano.
                                      MQ-2, MQ-3, MQ-4,MQ-6, MQ-7,MQ-9, MQ-135

                                      With sketch form robosensor https://forum.mysensors.org/topic/1595/mq2-sensor-w-airquality-sketch/2

                                      I get data like MQ-7:1020 ,MQ135: 294, MQ-2:191

                                      So it looks really good.
                                      As i would like to have also the correct names an value names of the sensor and a correct calibration I think I should use a sketch like AirQuality-Multiple_Gas_Sensor1_4.ino
                                      But I only see 3 of my 7 sensors in this sketch.

                                      What would be a good sketch for my 7 sensors ??

                                      Thanks
                                      Jorg

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                                      • walk_portoW Offline
                                        walk_portoW Offline
                                        walk_porto
                                        wrote on last edited by
                                        #241

                                        Hello everybody,

                                        I am working with an Arduino Uno and a MQ135 module arduino : http://www.sainsmart.com/sainsmart-mq135-sensor-air-quality-sensor-hazardous-gas-detection-module-arduino.html

                                        I can get back data from this sensor, I got 100 ppm when I launched serial terminal after compiling and uploading this code below.

                                        int sensorValue;
                                        
                                        void setup()
                                        {
                                          Serial.begin(9600);      // sets the serial port to 9600
                                        }
                                        
                                        void loop()
                                        {
                                          sensorValue = analogRead(0);       // read analog input pin 0
                                          Serial.println(sensorValue, DEC);  // prints the value read
                                          delay(100);                        // wait 100ms for next reading
                                        }
                                        

                                        But, I would like to get back data from gases like NH3, NOx, alcohol, benzene, smoke and CO2 . I read a lot of topics and the datasheets of the sensor but I don't see how to do.

                                        If someone could help me, it will be great.

                                        Thanks.

                                        AtmosChemeA 1 Reply Last reply
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                                        • walk_portoW walk_porto

                                          Hello everybody,

                                          I am working with an Arduino Uno and a MQ135 module arduino : http://www.sainsmart.com/sainsmart-mq135-sensor-air-quality-sensor-hazardous-gas-detection-module-arduino.html

                                          I can get back data from this sensor, I got 100 ppm when I launched serial terminal after compiling and uploading this code below.

                                          int sensorValue;
                                          
                                          void setup()
                                          {
                                            Serial.begin(9600);      // sets the serial port to 9600
                                          }
                                          
                                          void loop()
                                          {
                                            sensorValue = analogRead(0);       // read analog input pin 0
                                            Serial.println(sensorValue, DEC);  // prints the value read
                                            delay(100);                        // wait 100ms for next reading
                                          }
                                          

                                          But, I would like to get back data from gases like NH3, NOx, alcohol, benzene, smoke and CO2 . I read a lot of topics and the datasheets of the sensor but I don't see how to do.

                                          If someone could help me, it will be great.

                                          Thanks.

                                          AtmosChemeA Offline
                                          AtmosChemeA Offline
                                          AtmosCheme
                                          wrote on last edited by
                                          #242

                                          @walk_porto

                                          I think that the only way you are going to be able to distinguish between different gases is to have a known concentration of that gas and adjust load resistance. This sensor will detect all of these gase because of cross sensitivity to the gases mentioned in the filament. You can not use just one MQ135 sensor and get readings for all of the gases.

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