MQ 131 when detecting ozone

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...

The [u]minimum[/u] preheat time is 48 hours.

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

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!

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!

Perhaps there was not enough ozone to detect.

If you want to understand the output, you [u]must[/u] 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.

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 doesnโ€™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 https://github.com/ostaquet/Arduino-MQ131-driver, you will find useful information in the code ;-) Kind regards, Olivier

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.