- More than 400 PPM of ozone from my product.
- Hardware Configuration
- Arduino Uno + Arduino Uno Compatible I2C Shield + Ozone Gas Sensor 12-Bit (MQ131)
- Connect the power for 3 days and heat the sensor.
- The wrong amount of ozone is measured.
- As the amount of ozone increases, the measured value of MQ131 decreases.
- What is it? Ask for help.
- Attachment (code, photo)
#include <Wire.h>
#include <ADC121C_MQ131.h>
ADC121C_MQ131 mq131;
void setup(void)
{
Serial.begin(9600);
// The address can be changed making the option of connecting multiple devices
mq131.getAddr_ADC121C_MQ131(ADC121C_MQ131_DEFAULT_ADDRESS); // 0x50, 1010000
// mq131.getAddr_ADC121C_MQ131(ADC121C_MQ131_ADDRESS_FLGND); // 0x51, 1010001
// mq131.getAddr_ADC121C_MQ131(ADC121C_MQ131_ADDRESS_FLVA); // 0x52, 1010010
// mq131.getAddr_ADC121C_MQ131(ADC121C_MQ131_ADDRESS_GNDFL); // 0x54, 1010100
// mq131.getAddr_ADC121C_MQ131(ADC121C_MQ131_ADDRESS_GNDGND); // 0x55, 1010101
// mq131.getAddr_ADC121C_MQ131(ADC121C_MQ131_ADDRESS_GNDVA); // 0x56, 1010110
// mq131.getAddr_ADC121C_MQ131(ADC121C_MQ131_ADDRESS_VAFL); // 0x58, 1011000
// mq131.getAddr_ADC121C_MQ131(ADC121C_MQ131_ADDRESS_VAGND); // 0x59, 1011001
// mq131.getAddr_ADC121C_MQ131(ADC121C_MQ131_ADDRESS_VAVA); // 0x5A, 1011010
// The Automatic Conversion Mode, Alert Hold, Alert Flag Enable,
// Alert Pin Enable and ALERT pin Polarity
// can be changed via the following functions
mq131.setCycleTime(CYCLE_TIME_32); // Tconvert x 32, 27 ksps
// mq131.setCycleTime(AUTOMATIC_MODE_DISABLED); // Automatic Mode Disabled, 0 ksps
// mq131.setCycleTime(CYCLE_TIME_64); // Tconvert x 64, 13.5 ksps
// mq131.setCycleTime(CYCLE_TIME_128); // Tconvert x 128, 6.7 ksps
// mq131.setCycleTime(CYCLE_TIME_256); // Tconvert x 256, 3.4 ksps
// mq131.setCycleTime(CYCLE_TIME_512); // Tconvert x 512, 1.7 ksps
// mq131.setCycleTime(CYCLE_TIME_1024); // Tconvert x 1024, 0.9 ksps
// mq131.setCycleTime(CYCLE_TIME_2048); // Tconvert x 2048, 0.4 ksps
mq131.setAlertHold(ALERT_HOLD_CLEAR); // Alerts will self-clear
// mq131.setAlertHold(ALERT_HOLD_NOCLEAR); // Alerts will not self-clear
mq131.setAlertFlag(ALERT_FLAG_DISABLE); // Disables alert status bit in the Conversion Result register
// mq131.setAlertFlag(ALERT_FLAG_ENABLE); // Enables alert status bit in the Conversion Result register
mq131.setAlertPin(ALERT_PIN_DISABLE); // Disables the ALERT output pin
// mq131.setAlertPin(ALERT_PIN_ENABLE); // Enables the ALERT output pin
mq131.setPolarity(POLARITY_LOW); // Sets the ALERT pin to active low
// mq131.setPolarity(POLARITY_HIGH); // Sets the ALERT pin to active high
mq131.begin();
// Calibrate your Sensor to Obtain Precise Value
mq131.Calibration();
// We Deduce Resistance of the Sensor in Clean Air (Ro) in the Serial Port
// Serial.print("Ro = ");
// Serial.println(mq131.Measure_Ro());
}
void loop(void)
{
byte error;
int8_t address;
address = mq131.ADC121C_MQ131_i2cAddress;
// The i2c_scanner uses the return value of
// the Write.endTransmisstion to see if
// a device did acknowledge to the address.
Wire.beginTransmission(address);
error = Wire.endTransmission();
if (error == 0)
{
uint16_t result;
Serial.println("Getting Gas Readings from ADC121C_MQ131");
Serial.println(" ");
// Serial.print("Rs/Ro Ratio: ");
// Serial.println(mq131.Measure_RatioRsRo());
// The Graph at fig of datasheet (sensitivity characteristics of the MQ-131)
// seems a power function y = a*x^b
// so ppm = a*(Rs/Ro)^b
// Using Power Regression, you can obtain Slope (a), and Logarithmic Value of ppm (b) for Ozone (O3)!
// From the graph, we get points for O3: (5.0, 6.0), (100.0, 0.4)
Serial.print("Concentration of Ozone in ppb is: ");
float ppmO3 = mq131.Measure_Ozone(-0.90, 0.69);
Serial.print(ppmO3, 3);
Serial.println(" ppm ");
Serial.print("Concentration of Ozone in ppm is: ");
Serial.print(ppmO3*1000, 3);
Serial.println(" ppb ");
Serial.println(" ");
Serial.println(" *************************** ");
Serial.println(" ");
}
else
{
Serial.println("ADC121C_MQ131 Disconnected!");
Serial.println(" ");
Serial.println(" ************ ");
Serial.println(" ");
}
delay(1000);
}
