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: A2
Serial: 25600003
Firmware Version: 1.0.0
Timestamp: 2025-08-20T12:03:59
Length: 15.02
Temperature Ext: 25.8
Loc Position: 47.052968 8.257644
BATLOGGER|Trigger|Frequency: 62.6

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="A2" Rev="1">
      <Firmware>1.0.0</Firmware>
      <SN>25600003</SN>
      <Filename>00030000_CH1.wav</Filename>
      <DateTime>20.08.2025 12:03:59</DateTime>
      <Alias>A2_0003</Alias>
      <Profile>BLC2-Profile</Profile>
      <Duration>15.0 Sec</Duration>
      <Samplerate>384000 Hz</Samplerate>
      <Temperature>26 C</Temperature>
      <BattVoltage>4.1 V</BattVoltage>
      <GPS>
              <Valid>yes</Valid>
              <Position>47.05297 8.25764</Position>
      </GPS>
      <Microphone>
              <WavTrackNo>1</WavTrackNo>
              <ChannelNo>1</ChannelNo>
              <ChAlias>Channel 1</ChAlias>
              <SerNo>22101025110219</SerNo>
              <Manufactured>11/2025</Manufactured>
              <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>1500</PostTriggerTime>
              <MaxDuration>15000</MaxDuration>
      </TrgSettings>
      <TrgValues>
              <Event>sound</Event>
              <PeakFreq>62625</PeakFreq>
              <CrestFactor>8.15</CrestFactor>
              <SoundLevel>7.5 %</SoundLevel>
              <PeriodTrig>100.2</PeriodTrig>
              <FFTVal>5.97</FFTVal>
              <PeakArea>13.99</PeakArea>
              <PeakDiffVar>1.45</PeakDiffVar>
              <TriggerCond>1</TriggerCond>
      </TrgValues>
      <Sensor>
              <ChannelNo>1</ChannelNo>
              <SerNo>22101025110219</SerNo>
              <Temperature>26 C</Temperature>
              <Humidity>59 %r.H</Humidity>
      </Sensor>
      <Spectrum>0,0,0,0,0,0,0,0,0,0,1,1,1,1,2,2,2,2,3,3,4,4,4,4,4,4,5,6,6,6,6,6,7,7,8,9,14,18,53,54,99,69,57,40,54,36,31,34,22,12,12,12,13,15,16,16,18,23,80,33,17,14,13,12,11,12,12,10,10,12,10,10,11,11,10,11,16,19,20,35,34,44,31,46,42,32,22,28,35,47,41,49,71,55,52,28,23,10,9,9,10,10,10,11,12,11,12,13,14,22,22,20,16,17,20,32,27,26,27,31,33,36,30,32,26,29,34,37,34,19,22,22,25,40,41,29,39,49,28,28,34,25,22,25,20,14,11,11,10,10,10,10,10,11,11,10,10,10,10,10,11,10,11,10,10,9,9,10,10,10,10,9,9,8,8,8,7,7,7,6,6,6,5,5,5,5,4,4,4,4,4,4,3,3,3,3,3,3,3,3,2,3,3,2,2,2,2,2,2,2,2,2,2,2,3,3,3,3,3,3,3,3,3,3,3,3,3,2,2,2,2,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0</Spectrum>
      <Calls>
              <Call pos="2.824" chan="0" freq="28875" dur="11" int="6.073" lev="8.1" />
              <Call pos="2.853" chan="0" freq="43500" dur="3" int="4.975" lev="5.4" />
              <Call pos="2.867" chan="0" freq="103125" dur="3" int="6.449" lev="7.1" />
              <Call pos="2.883" chan="0" freq="30375" dur="3" int="5.104" lev="7.2" />
              <Call pos="2.904" chan="0" freq="70125" dur="3" int="4.710" lev="8.0" />
              <Call pos="2.915" chan="0" freq="30375" dur="11" int="6.606" lev="6.8" />
              <Call pos="2.941" chan="0" freq="70500" dur="3" int="6.198" lev="6.9" />
              <Call pos="2.957" chan="0" freq="30375" dur="3" int="6.145" lev="6.9" />
              <Call pos="2.979" chan="0" freq="95625" dur="8" int="6.914" lev="7.5" />
              <Call pos="3.011" chan="0" freq="28875" dur="3" int="4.871" lev="6.2" />
              <Call pos="3.032" chan="0" freq="30375" dur="19" int="7.116" lev="8.6" />
              <Call pos="3.059" chan="0" freq="30375" dur="3" int="4.913" lev="6.5" />
              <Call pos="3.069" chan="0" freq="28875" dur="8" int="6.951" lev="6.9" />
              <Call pos="3.091" chan="0" freq="28875" dur="3" int="4.781" lev="6.8" />
              <Call pos="3.101" chan="0" freq="31500" dur="3" int="4.819" lev="5.7" />
      </Calls>
      <PosS>3.032</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.:

SN0003 20.08.2025 12:00:48 I BATLOGGER A2 25600003 power on (SWRev: 1.0.0/BETA HWRev: 1 PN: 027677027 BLE: 1.5.0 Ana: 1 ExtP: 0)
SN0003 20.08.2025 12:00:49 I CH1: 2 (Mic: 22101025110219 Sens: 22101025110219 FW: 104)
SN0003 20.08.2025 12:01:09 I BLE Connected
SN0003 20.08.2025 12:01:18 I Connected to: Pixel 6; App: 2.0.6
SN0003 20.08.2025 12:01:36 I Updated RTC Date/Time to 20.08.2025 10:01:36.6 UTC. Difference: 15776 ms
SN0003 20.08.2025 12:03:54 I Updated location to 47.052968/8.257644
SN0003 20.08.2025 12:03:54 I Recording session started as A2_0003 with profile: BLC2-Profile
SN0003 20.08.2025 12:03:54 I CH1: Channel 1 (Mic: 22101025110219 Sens: 22101025110219 FW: 104)
SN0003 20.08.2025 12:03:57 I Microphone Test CH1 (221.010-25110219) SNR @40kHz: 46.5dB
SN0003 20.08.2025 12:03:59 I Record mode started
SN0003 20.08.2025 12:04:34 I Connected to: Pixel 6; App: 2.0.6
SN0003 20.08.2025 12:04:37 I Updated RTC Date/Time to 20.08.2025 10:04:37.8 UTC. Difference: 581 ms
SN0003 20.08.2025 12:04:39 I Record mode stopped
SN0003 20.08.2025 12:04:39 I Recording session aborted
SN0003 20.08.2025 12:05:00 I BLE Disconnected