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 IｲC 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 IｲC 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 CO竄� 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>