The sensor starts up seemingly properly and for a short time records about 400 ppm. Then it goes to a high voltage and returns large fluctuations. Does not respond to increases or decreases in CO2. Have checked with a more expensive sensor.
Code used to monitor is provided below. I have commented out some lines so I coudl use the serial plotter. Image of plot after startup is attached, no difference after some hours. Note sensor was placed in a glass jar to buffer against large CO2 fluctuations. I have had some experience with CO2 monitoring.
There is no other sensor attached to the Arduino.
/***************************************************
- Infrared CO2 Sensor0-5000ppm
- GNU Lesser General Public License.
- See http://www.gnu.org/licenses/ for details.
- All above must be included in any redistribution
- ****************************************************/
int sensorIn = A0;
void setup(){
Serial.begin(9600);
// Set the default voltage of the reference voltage
analogReference(DEFAULT);
}
void loop(){
//Read voltage
int sensorValue = analogRead(sensorIn);
// The analog signal is converted to a voltage
float voltage = sensorValue*(5000/1024.0);
if(voltage == 0)
{
Serial.println(“Fault”);
}
else if(voltage < 400)
{
Serial.println(“preheating”);
}
else
{
int voltage_diference=voltage-400;
float concentration=voltage_diference*50.0/16.0;
// Print Voltage
//Serial.print(“voltage:”);
//Serial.print(voltage);
//Serial.println(“mv”);
//Print CO2 concentration
Serial.println(concentration);
//Serial.println(“ppm”);
}
delay(1000);
}
