Recordings and Files¶

Audio file ”xxxxxxxx.wav”¶

Under the file name “xxxxxxxx.wav”, the recorded data is saved in a standardized audio file, a so-called WAVE file, on the microSD card. (Example 10160435.wav) The first 4 digits are the device number of the BATLOGGER and the other 4 digits are a consecutive numbering of the recording files on the inserted microSD card. The example above is therefore the 435th recording on this microSD card from the BATLOGGER with the device number 1016. The .wav file essentially contains the entire measured values as “raw data” (without compression) and a format-specific “header” which, among other things, also contains the sampling frequency. Additionally, the file contains another sub-chunk for GUANO metadata (see below). At the same time as this recording data, an information file (.xml) with all recording data is saved under the same file number (see below). The recordings can optionally be saved in subfolders (daily, weekly, monthly, per start). The .wav files can be read with various audio programs or with bat-specific sound analysis software and displayed as time signal or spectrogram. The latter is the most reliable way to determine the species.

GUANO metadata¶

GUANO is a cross-device standard for storing bat detector metadata directly in the .wav file. Further information can be found at https://guano-md.org. The guano subchunk is at the end of the file. BATLOGGER-specific data is stored under the namespace “BATLOGGER”.

Example:

GUANO|Version: 1.0
Make: BATLOGGER
Model: S2
Firmware Version: 1.0.0
Serial: 1001
Original Filename: 10010003.wav
Timestamp: 2019-01-21T22:14:29
Length: 7.02
Samplerate: 312500
Temperature Ext: 23
BATLOGGER|Trigger|Frequency: 52

Recording information file ”xxxxxxxx.xml”¶

For each “xxxxxxxxxx.wav” file stored, an additional information file “xxxxxxxxxx.xml” is stored with the same number with various metadata on recording time, date, location, temperature and device settings (parameters).

Example of the content of an .xml info file.:

<BatRecord Model="S2" Rev="1">
  <Firmware>0.1.3</Firmware>
  <SN>0004</SN>
  <Filename>00040000.wav</Filename>
  <DateTime>06.05.2020 21:01:39</DateTime>
  <Duration>1.5 Sec</Duration>
  <Samplerate>384000 Hz</Samplerate>
  <Temperature>24.0 C</Temperature>
  <BattVoltage>4.1 V</BattVoltage>
  <GPS>
    <Valid>yes</Valid>
    <Position>47.04678 8.30131</Position>
    <Altitude>438 m</Altitude>
    <SatsUsed>4</SatsUsed>
  </GPS>
  <Microphone>
    <MicChannelNo>0</MicChannelNo>
    <Gain>2 dB</Gain>
  </Microphone>
  <TrgSettings>
    <MinFreq>15000</MinFreq>
    <MaxFreq>192000</MaxFreq>
  </TrgSettings>
  <TrgValues>
    <Event>sound</Event>
    <PeakFreq>32250</PeakFreq>
    <CrestFactor>12.63</CrestFactor>
    <Level>28138.9 dB SPL</Level>
  </TrgValues>
</BatRecord>

Log file “BATREC.log”¶

The batrec.log file gives you an overview on what happened with the device. It helps you to troubleshoot or to make sure that your device recorded during the times you wanted it to.

Example of the content of an .xml info file.:

SN0016 ??.??.???? ??:??:?? I BATLOGGER S2 21170016 power on (SWRev: 0.3.1/Alpha HWRev: 2 PN: 025326030 BLE: 0.5.0)
SN0016 ??.??.???? ??:??:?? I BLE Connected
SN0016 06.10.2021 12:39:17 I Updated RTC Date/Time to 06.10.2021 10:39:17 UTC. Difference: 38341875 ms
SN0016 06.10.2021 12:40:04 I Updated location to 47.052999/8.257651
SN0016 06.10.2021 12:40:04 I Recording session started
SN0016 06.10.2021 12:40:14 I BLE Disconnected
SN0016 06.10.2021 12:40:15 I Sleeping until 18:42
SN0016 06.10.2021 18:42:41 I Record mode started
SN0016 06.10.2021 19:00:00 I State: T[°C]=17.6, VB[V]=4.02 (20.7°C 83.0%), VU[V]=0.00
SN0016 06.10.2021 20:00:00 I State: T[°C]=17.9, VB[V]=4.01 (21.2°C 82.0%), VU[V]=0.00
SN0016 06.10.2021 21:00:00 I State: T[°C]=17.8, VB[V]=4.00 (21.2°C 81.0%), VU[V]=0.01
SN0016 06.10.2021 22:00:00 I State: T[°C]=17.8, VB[V]=3.99 (20.9°C 80.0%), VU[V]=0.01
SN0016 06.10.2021 23:00:00 I State: T[°C]=17.6, VB[V]=3.98 (20.9°C 78.0%), VU[V]=0.00
SN0016 07.10.2021 00:00:00 I State: T[°C]=17.5, VB[V]=3.97 (20.7°C 77.0%), VU[V]=0.00
SN0016 07.10.2021 01:00:00 I State: T[°C]=17.3, VB[V]=3.96 (20.7°C 76.0%), VU[V]=0.00
SN0016 07.10.2021 02:00:00 I State: T[°C]=17.3, VB[V]=3.95 (20.7°C 75.0%), VU[V]=0.01
SN0016 07.10.2021 03:00:00 I State: T[°C]=17.2, VB[V]=3.94 (20.4°C 74.0%), VU[V]=0.00
SN0016 07.10.2021 04:00:00 I State: T[°C]=17.2, VB[V]=3.93 (20.4°C 73.0%), VU[V]=0.01
SN0016 07.10.2021 05:00:00 I State: T[°C]=17.2, VB[V]=3.92 (20.4°C 72.0%), VU[V]=0.01
SN0016 07.10.2021 06:00:00 I State: T[°C]=16.9, VB[V]=3.92 (20.4°C 71.0%), VU[V]=0.00
SN0016 07.10.2021 07:00:00 I State: T[°C]=17.2, VB[V]=3.91 (20.4°C 70.0%), VU[V]=0.00
SN0016 07.10.2021 07:48:14 I Record mode stopped
SN0016 07.10.2021 07:49:37 I Sleeping until 18:40