3.6
Ancillary Sensors
All SoundTraps include temperature and accelerometer sensors. Logging of these is enabled by
selecting the corresponding checkbox in the deployment screen of the SoundTrap Host software.
Note that logging can only take place while the recorder is awake, meaning that sensor logging is
subject to the same duty cycle as that configured for audio recording.
Sensor data is offloaded alongside audio data, and is decompressed into CSV format files, one file
per sensor, per audio recording.
Temperature data is recorded in degrees Celsius. Note
that these measurements are only valid when the
instrument is fully submerged, and that
measurements made in air will be incorrect due to
internal heat build-up, particularly when connected to
USB and recharging the battery.
Accelerometer data is recorded as unscaled 16 bit
values r/- 32768. The full scale sensitivity of
the accelerometer is +/- 2 g, meaning each count
represents 61 ug. The orientation of the
accelerometers axis for the ST300 is shown in the
adjacent diagram. Older ST200 models have the X and
Y axis transposed. Note that the X & Y axis are not
easily discerned as the rotation of the sensor within
the housing varies. This is generally of little
consequence for inclination and cable strum
applications, but where required can be measured by placing the recorder in a known static
orientation, observing the resultant measurements and solving for gravitational acceleration. For
those wanting more detailed information on the accelerometer sensor characteristics, please refer
to the datasheet for the Kionix KXTI9.
Figure 4 - Accelerometer axis for ST300
