A simple arduino library for MH-Z19 by using SoftwareSerial

Example

#define CO2_PWM_PIN 5
#define CO2_UART_TX_PIN 9
#define CO2_UART_RX_PIN 10

MH_Z19 mhz19(CO2_PWM_PIN, CO2_UART_TX_PIN, CO2_UART_RX_PIN);

void setup() {
    // ...

    mhz19.setup();

    // ...
}

void loop(void) {
    // ...

    Serial1.println(mhz19.read_pwm_value());
    Serial1.println(mhz19.read_uart_value());

    // ...
}

Links

1. MHZ19 Spec on Rev Space