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: C2
Serial: 23240008
Firmware Version: 0.0.19
Timestamp: 2023-07-05T21:44:52
Length: 1.50
Temperature Ext: 19.7
Loc Position: 47.046829 8.301089
BATLOGGER|Trigger|Frequency: 23.6

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.:

<?xml version="1.0" encoding="utf-8"?>
<BatRecord Model="C2" Rev="1">
      <Firmware>0.0.19</Firmware>
      <SN>23240008</SN>
      <Filename>00080000_CH1.wav</Filename>
      <DateTime>05.07.2023 21:44:52</DateTime>
      <Profile>C2_0008</Profile>
      <Duration>1.5 Sec</Duration>
      <Samplerate>384000 Hz</Samplerate>
      <Temperature>20 C</Temperature>
      <BattVoltage>4.1 V</BattVoltage>
      <GPS>
              <Valid>yes</Valid>
              <Position>47.04683 8.30109</Position>
      </GPS>
      <Microphone>
              <WavTrackNo>1</WavTrackNo>
              <ChannelNo>1</ChannelNo>
              <SerNo>22101023240020</SerNo>
              <Manufactured>24/2023</Manufactured>
              <LastCalib>15/2023</LastCalib>
              <HasTriggered>1</HasTriggered>
              <Gain>+18 dB</Gain>
      </Microphone>
      <TrgSettings>
              <MinFreq>16125</MinFreq>
              <MaxFreq>150000</MaxFreq>
              <CrestFactor>7.00</CrestFactor>
              <PeriodTrig>150.0</PeriodTrig>
              <MinSoundLevel>1.0 %</MinSoundLevel>
              <MinFFTVal>5.00</MinFFTVal>
              <MinPeakArea>10.00</MinPeakArea>
              <MaxPeakDiffVar>30.00</MaxPeakDiffVar>
              <TriggerType>2</TriggerType>
              <TriggerVer>1</TriggerVer>
              <PreTriggerTime>500</PreTriggerTime>
              <PostTriggerTime>1000</PostTriggerTime>
              <MaxDuration>10000</MaxDuration>
      </TrgSettings>
      <TrgValues>
              <Event>sound</Event>
              <PeakFreq>23625</PeakFreq>
              <CrestFactor>10.11</CrestFactor>
              <SoundLevel>3.6 %</SoundLevel>
              <PeriodTrig>199.7</PeriodTrig>
              <FFTVal>2.74</FFTVal>
              <PeakArea>6.04</PeakArea>
              <PeakDiffVar>0.56</PeakDiffVar>
              <TriggerCond>2</TriggerCond>
      </TrgValues>
      <Sensor>
              <ChannelNo>1</ChannelNo>
              <SerNo>22101023240020</SerNo>
              <Temperature>20 C</Temperature>
              <Humidity>63 %r.H</Humidity>
      </Sensor>
      <Spectrum>0,0,0,0,0,0,3,0,7,2,2,6,8,6,8,13,11,21,15,16,15,12,26,14,30,15,15,23,18,25,38,175,18,11,32,20,26,24,13,9,11,16,16,20,7,15,23,11,12,0,13,23,23,14,23,31,11,6,19,33,8,18,23,30,17,22,21,18,15,34,23,12,27,32,27,20,18,12,10,29,10,15,13,21,36,17,22,22,10,22,15,22,27,34,18,23,9,31,14,46,15,38,34,32,30,34,26,46,32,27,33,32,27,59,48,24,38,35,35,27,18,38,26,19,12,23,21,20,20,28,13,45,23,27,7,34,16,16,20,19,21,15,16,25,25,15,18,20,14,13,14,26,21,16,18,10,13,15,9,20,6,14,15,20,24,10,23,24,14,22,13,6,18,18,26,12,14,14,11,8,20,2,10,16,14,17,18,10,24,18,10,27,10,16,12,8,13,7,20,11,9,18,2,9,3,15,20,16,18,8,6,6,8,7,4,8,2,9,4,6,4,6,6,7,7,0,2,7,0,6,0,2,0,2,0,3,0,3,2,0,2,2,2,2,0,0,0,0,0,0,0,0,0,0,0,0</Spectrum>
      <Calls>
              <Call pos="0.501" freq="23625" dur="3" int="2.736" lev="3.6" />
      </Calls>
      <PosS>0.501</PosS>
</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.:

SN0008 05.07.2023 19:29:16 I BATLOGGER C2 23240008 power on (SWRev: 0.0.19/ALPHA HWRev: 0 PN: 000000000 BLE: 1.3.87 Ana: 0 ExtP: 1)
SN0008 05.07.2023 19:29:17 I CH0: 2, CH1: 0
SN0008 05.07.2023 19:29:17 I BLNC: 1 (FW: 0.1.0 Modem: mfw_nrf9160_1.3.5 IMEI: 351516179784483 ICCID: 89882280666074847603)
SN0008 05.07.2023 19:29:25 I BLE Connected
SN0008 05.07.2023 19:29:27 I Connected to: Pixel 6; App: 1.4.0
SN0008 05.07.2023 19:29:28 I Updated RTC Date/Time to 05.07.2023 17:29:28.4 UTC. Difference: 837 ms
SN0008 05.07.2023 19:31:21 I Microphone Test CH1 (221.010-23240020) SNR @40kHz: 51.1dB
SN0008 05.07.2023 19:39:17 I Updated location to 47.046829/8.301089
SN0008 05.07.2023 19:39:17 I Recording session started
SN0008 05.07.2023 19:41:23 I BLE Disconnected
SN0008 05.07.2023 19:41:24 I Sleeping until 21:09
SN0008 05.07.2023 21:09:33 I CH0: 2, CH1: 0
SN0008 05.07.2023 21:09:34 I Record mode started
SN0008 05.07.2023 22:00:00 I State: T[°C]=20, VB[V]=4.13 (95%), VU[V]=0.0, EP[W]=0.0
SN0008 05.07.2023 23:00:00 I State: T[°C]=20, VB[V]=4.13 (95%), VU[V]=0.0, EP[W]=0.0
SN0008 06.07.2023 00:00:00 I State: T[°C]=20, VB[V]=4.13 (95%), VU[V]=0.0, EP[W]=0.0
SN0008 06.07.2023 01:00:00 I State: T[°C]=20, VB[V]=4.12 (94%), VU[V]=0.0, EP[W]=0.0
SN0008 06.07.2023 02:00:00 I State: T[°C]=20, VB[V]=4.12 (94%), VU[V]=0.0, EP[W]=0.0
SN0008 06.07.2023 03:00:00 I State: T[°C]=19, VB[V]=4.12 (94%), VU[V]=0.0, EP[W]=0.0
SN0008 06.07.2023 04:00:00 I State: T[°C]=18, VB[V]=4.12 (93%), VU[V]=0.0, EP[W]=0.0
SN0008 06.07.2023 05:00:00 I State: T[°C]=18, VB[V]=4.11 (93%), VU[V]=0.0, EP[W]=0.0
SN0008 06.07.2023 05:53:30 I Time window 1 done
SN0008 06.07.2023 05:53:31 I Record mode stopped
SN0008 06.07.2023 05:53:31 I Sleeping until 21:09