NAME

    Device::Chip::SCD4x - chip driver for SCD40 and SCD41

SYNOPSIS

       use Device::Chip::SCD4x;
       use Future::AsyncAwait;
    
       my $chip = Device::Chip::SCD4x->new;
       await $chip->mount( Device::Chip::Adapter::...->new );
    
       await $chip->start_periodic_measurement;
    
       while(1) {
          await Future::IO->sleep(1);
    
          my ( $co2, $temp, $humid ) = await $chip->maybe_read_measurement
             or next;
    
          printf "CO2 concentration=%dppm  ", $co2;
          printf "Temperature=%.2fC  ", $temp;
          printf "Humidity=%.2f%%\n", $hum;
       }

DESCRIPTION

    This Device::Chip subclass provides specific communication to a
    Sensirion SCD40 or SCD41 attached to a computer via an I²C adapter.

    The reader is presumed to be familiar with the general operation of
    this chip; the documentation here will not attempt to explain or define
    chip-specific concepts or features, only the use of this module to
    access them.

MOUNT PARAMETERS

 addr

    The I²C address of the device. Can be specified in decimal, octal or
    hex with leading 0 or 0x prefixes.

METHODS

    The following methods documented in an await expression return Future
    instances.

 read_config

       $config = await $chip->read_config;

    Returns a HASH reference containing the compensation values from chip
    config.

       temperature_offset # in degrees C
       sensor_altitude    # in metres
       ambient_pressure   # in hPa

 start_periodic_measurement

       await $chip->start_periodic_measurement;

    Starts periodic measurement mode.

 read_measurement

       ( $co2concentration, $temperature, $humidity ) = await $chip->read_measurement();

    Returns the latest sensor reading values. Returns a 3-element list,
    containing the COâ‚‚ concentration in PPM, temperature in degrees C, and
    humidity in %RH.

 maybe_read_measurement

       ( $co2concentration, $temperature, $humidity ) = await $chip->maybe_read_measurement();

    If the sensor has a new measurement ready, returns it. Otherwise,
    returns the last successful measurement reading. After initial startup,
    this will return an empty list before the first reading is available.

 get_serial_number

       $bytes = await $chip->get_serial_number;

    Returns a 6-byte encoding of the chip's internal serial number.

AUTHOR

    Paul Evans <leonerd@leonerd.org.uk>