NAME

       sense_rec - Sense HAT data recorder

       Records  sensor  readings  from  the  Raspberry  Pi Sense HAT in real time, outputting the
       results to a file for later playback or  analysis.  This  is  most  useful  for  preparing
       records  of experiments for use with the Sense HAT emulator. For example, a recording of a
       Sense HAT being dropped, a recording of  a  HAB  flight,  a  recording  of  the  cycle  of
       temperature over a few days, etc.

SYNOPSIS

          sense_rec [-h] [--version] [-q] [-v] [-l FILE] [-P] [-c CONFIG]
                    [-d DURATION] [-f] output

DESCRIPTION

       -h, --help
              show this help message and exit

       --version
              show this program's version number and exit

       -q, --quiet
              produce less console output

       -v, --verbose
              produce more console output

       -l FILE, --log-file FILE
              log messages to the specified file

       -P, --pdb
              run under PDB (debug mode)

       -c FILE, --config FILE
              the Sense HAT configuration file to use (default: /etc/RTIMULib.ini)

       -d SECS, --duration SECS
              the  duration  to  record  for  in  seconds  (default: record until terminated with
              Control-C)

       -i SECS, --interval SECS
              the delay between each reading in  seconds  (default:  the  IMU  polling  interval,
              typically 0.003 seconds)

       -f, --flush
              flush  every record to disk immediately; reduces chances of truncated data on power
              loss, but greatly increases disk activity

EXAMPLES

       To record an experiment with the Sense HAT, simply execute sense_rec with the filename you
       wish to record the results:

          $ sense_rec experiment.hat

       By  default,  the  recording  will continue indefinitely. Press Control-C to terminate the
       recording. If you want to record for a specific  duration,  you  can  use  the  --duration
       option to specify the number of seconds:

          $ sense_rec --duration 10 short_experiment.hat

       This tool can be run simultaneously with scripts that use the Sense HAT. Simply start your
       script in one terminal, then open another to start sense_rec. Alternatively, you  can  use
       the shell's job control facilities to start recording in the background:

          $ sense_rec experiment.hat &
          $ python experiment.py
          ...
          $ kill %1

       WARNING:
          Be  aware  that  other  scripts  attempting to use the HAT's sensors will likely obtain
          different readings than they would have if run standalone.  Some of the  HAT's  sensors
          are  affected  by  their query-rate, and sense_rec drives all sensors at close to their
          maximum rate.

       If - is specified as the output file, sense_rec will write its output to stdout. This  can
       be  used  to reduce the disk space required for long output by piping the output through a
       compression tool like gzip:

          $ sense_rec - | gzip -c - > experiment.hat.gz

       When compressed in this manner the  data  typically  uses  approximately  3Kb  per  second
       (without  gzip  the  recording  will use approximately 10Kb of disk space per second). Use
       gunzip to de-compress the data for playback or analysis:

          $ gunzip -c experiment.hat.gz | sense_play -

       Another method of reducing the data usage is increasing the interval between readings (the
       default  is  the IMU polling interval which is an extremely short 3ms). Obviously a longer
       interval will reduce the "fidelity" of the recording; you will only see the sensors update
       at  each  interval  during  playback,  however  it  can  be extremely useful for very long
       recordings. For example, to record with a 1 second interval between readings for 24 hours:

          $ sense_rec -i 1 -d $((24*60*60)) one_day_experiment.hat

       Finally, you can use pipes in conjunction with sense_csv to produce CSV output directly:

          $ sense_rec - | sense_csv - experiment.csv

       Be warned that CSV data is substantially larger than the  binary  format  (CSV  data  uses
       approximately 25Kb per second at the default interval).

AUTHOR

       Raspberry Pi Foundation

COPYRIGHT

       2016-2021 Raspberry Pi Foundation