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: #


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.