WA002 Generating Files with No Data

    Generating Files with No Data #

    Problem ID Manufacturer Affected Firmware Affected hardware Status
    WA002 Wildlife Acoustics Unknown SM4, SM3 Major problem

    At some point during a deployment, the SM4s start generating small files, each about 128KB, each filled with NUL bytes. Probable cause: SD card full.

    We now believe the cause is low power from the main batteries.

    Update: For one deployment of 8 sensors we saw this problem a lot.

    Details: #

    TL;DR: there are two weeks of good data, and the third week is a write-off.

    • All the corrupt files happen towards the end of the deployment
    • There are 5121 corrupt files and 1608 valid files
    • The corrupt files did not take up too much space (only 380MB across all of the sensors)
    • Data collection is good for all sensors from Monday 12th November through to Monday 26th of November
    • The first sensor fails on the 26th
    • The last sensor fails on the 2nd of December
    • The last valid recording is 12:00 on the
    • Naively I would guess the sensors are running out of storage space
    • However, after failures start occurring some successful files still get recorded
    • The sensor tries to repeatedly record again when a file fails to record
    • If these sensors were running off solar power this behaviour would make sense.

    Examples: #

    sm4_failures_empty_file.png

    Example files

    Status #

    Major Problem

    Status with vendor #

    Not yet contacted WA

    Effects of the problem on common tools #

    Acoustics Workbench (Ecosounds, A2O): #

    • FFMPEG reports the file has having invalid data. “Invalid data found when processing input” so data can’t be harvested

    Workarounds #

    Filter out small files (less than 500KB) when analysing data.