MQ 131 when detecting ozone

Other Hardware Sensors
1

sorry for my english... :confused:

When detecting ozone should the voltage increase or decrease?
I bought a sensor "SainSmart MQ131 Gas Sensor Ozone Module For Arduino " https://www.sainsmart.com/sainsmart-mq131-gas-sensor-ozone-module-for-arduino-uno-mega2560-r3-raspberry-pi.html
For the moment i just measure the voltage (tension) : without ozone at the begining it was more than 4V, 3 hours later 3,3V and 24 h after about 2 V. More than 24h (but less than 48h) I produce ozone generating sparks with an induction coil...and the voltage is going down!

Is it logical? I thought the voltage will increase...

Thanks for your answers...

2

The minimum preheat time is 48 hours.

Useful data sheet http://www.winsen-sensor.com/d/files/semiconductor/mq131-low.pdf

3

Thank's i will try again, as if i have to wate because i will not be home for 4 days.

I have the same results than https://forum.arduino.cc/index.php?topic=447393.0: Anyways, whenever I try testing the sensor by exposing it to some ozone producing equipment, the value decreases, instead of increasing as if he like me heated the sensor less than 48h!

4

I have tried again after 4 days. The voltage was about 2.3V , i put some ozone but nothing happenned the voltage was the same!

5

Perhaps there was not enough ozone to detect.

If you want to understand the output, you must calibrate the sensor against one or more known concentrations of ozone gas.

You should ask the manufacturer for operating instructions and a circuit diagram of the module.

6

Hi,
There is two ways of using the MQ131:

  • directly the sensor itself (bare / naked sensor)
  • via a module
    I used to have a module and I remove the sensor from the module because the documentation doesn’t exist.
    The two important things are:
  1. You have to preheat the sensor for 48h at 5V to have consistent result.
  2. In order to compute the ppm/ppb, you have to calculate the Rs/R0 and apply the sensitivity curve on it.
    Just check my lib on GitHub - ostaquet/Arduino-MQ131-driver: Arduino driver for gas sensor MQ131 (Ozone / O3), you will find useful information in the code :wink:
    Kind regards,
    Olivier
7

Hii,
Ostaquet, I used your GitHub code, and I upload that in my board but its only showing " Calibration in progress..... " for a long time, do I have to leave it for 48 hours to calibrate or there is something wrong with my board or wiring.
please, ans.