Electrochemical Gas Sensors – Single sensor measurement example

Connections for this example

ℹ️

When using a single sensor, make sure to connect the LMPEN pin to the GND pin on the board. This ensures that the pin is set to LOW and that the LMP91000 is always enabled. For more information, look here.

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Initializing the sensor

To initialize the sensor, we must first include the library and create an instance of the sensor object with a configuration for the appropriate type (for this example, we are using an ammonia sensor). You can find all of the pre-defined configurations here.

// Include the library
#include "Electrochemical-Gas-Sensor-SOLDERED.h"

// Create the sensor object with the according type
ElectrochemicalGasSensor sensor(SENSOR_NH3);

Next, in the setup() function, we initialize the serial communication as well as the breakout board itself:

void setup()
{
    // Initialize serial communication
    Serial.begin(115200); 

    // Initialize the breakout
    if (!sensor.begin())
    {
        // Can't initialize? Notify the user and enter an infinite loop
        Serial.println("ERROR: Can't init the sensor! Check connections!");
        while (true)
            delay(100);
    }

    Serial.println("Sensor initialized successfully!");
}

sensor.begin()

Initializes the LMP91000 and ADS1115 on the board and establishes an I2C connection

Returns value: Boolean value, returns true if it was successful, false if it failed

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Taking a measurement

Finally, in the loop() function, we get the reading from the breakout board and print it to serial:

void loop()
{
    // Make the reading
    double reading = sensor.getPPM();

    // Print the reading with 5 digits of precision
    Serial.print("Sensor reading: ");
    Serial.print(reading, 5);
    Serial.println(" PPM");

    // Wait a bit before reading again
    delay(2500);
}

Serial monitor

sensor.getPPM()

Makes a measurement with the ADS1115 ADC and calculates the PPM value of the measured gas

Returns value: Double value, gas measurement in PPM (parts per million)

sensor.getPPB()

Make a measurement with the ADS1115 ADC and calculate the PPB value of the measured gas

Returns value: Double value, gas measurement in PPB (parts per billion)

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Full example

See the full example here:

// Include the required library
#include "Electrochemical-Gas-Sensor-SOLDERED.h"

// Create the sensor object with the according type
ElectrochemicalGasSensor sensor(SENSOR_NH3);

void setup()
{
    Serial.begin(115200); // For debugging

    // Initialize the breakout
    if (!sensor.begin())
    {
        // Can't initialize? Notify the user and enter an infinite loop
        Serial.println("ERROR: Can't init the sensor! Check connections!");
        while (true)
            delay(100);
    }

    Serial.println("Sensor initialized successfully!");
}

void loop()
{
    // Make the reading
    double reading = sensor.getPPM();

    // Print the reading with 5 digits of precision
    Serial.print("Sensor reading: ");
    Serial.print(reading, 5);
    Serial.println(" PPM");

    // Wait a bit before reading again
    delay(2500);
}