I've been using my mq131 low concentration module for a while, and I burn it out for like 48 hours before using. After that, i got normal values ( 22 micrograms/m3). But a few day ago i tried to use it with the Bluetooth hc-05 and suddenly i couldn't see any changes on my Bluetooth app on android). After that, i tried to check it up on my serial monitor and i only get ovf or very big values. I have no idea what happens, i always power it up on 5V and I've been using this code:
/*******************************************************************************
* Sample the ozone concentration every 60 seconds
*
* Example code base on low concentration sensor (black bakelite)
* and load resistance of 1MOhms
*
* Schematics and details available on https://github.com/ostaquet/Arduino-MQ131-driver
******************************************************************************
* MIT License
*
* Copyright (c) 2018 Olivier Staquet
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*******************************************************************************/
#include <MQ131.h>
void setup() {
Serial.begin(115200);
// Init the sensor
// - Heater control on pin 2
// - Sensor analog read on pin A0
// - Model LOW_CONCENTRATION
// - Load resistance RL of 1MOhms (1000000 Ohms)
MQ131.begin(2,A0, LOW_CONCENTRATION, 1000000);
Serial.println("Calibration parameters");
Serial.print("R0 = ");
Serial.print(MQ131.getR0());
Serial.println(" Ohms");
Serial.print("Time to heat = ");
Serial.print(MQ131.getTimeToRead());
Serial.println(" s");
}
void loop() {
Serial.println("Sampling...");
MQ131.sample();
Serial.print("Concentration O3 : ");
Serial.print(MQ131.getO3(PPM));
Serial.println(" ppm");
Serial.print("Concentration O3 : ");
Serial.print(MQ131.getO3(PPB));
Serial.println(" ppb");
Serial.print("Concentration O3 : ");
Serial.print(MQ131.getO3(MG_M3));
Serial.println(" mg/m3");
Serial.print("Concentration O3 : ");
Serial.print(MQ131.getO3(UG_M3));
Serial.println(" ug/m3");
delay(60000);
}
What could have happened? I observe that the R0 now is low, around 1900 ohms, compared to very big values that had a few days ago.