This design is the hardware for the Caracal Evo (2021) board variant. This is an acoustic array, specifically targetted towards unattended bioacoustic monitoring.

Specific features include:

• 8 bottom port MEMS microphones
• USB-DFU capable (can be easily flashed/programmed over USB)
• Power from USB or external (6-12V)
• Small, circular board (8.4 cm radius)
• Low cost BOM (~USD30 per unit in 100 qty)

An earlier version (shown in the left image below) has been trialled in Zimbabwe and Kenya.

This is a multichannel audio recorder, which allows for:

• precise, GPS-aided, timing between stations for Time Difference of Arrival (TDoA)
• the capability of estimating bearing/Angle of Arrival (AoA) from a single station

The plot below shows a hyena call recorded on two stations - top four plots are from Station A, bottom four plots are from Station B. Note the time delay between Station A and Station B.

This work has been published in:

Wijers, Matthew, Andrew Loveridge, David W. Macdonald, and Andrew Markham. "CARACAL: A versatile passive acoustic monitoring tool for wildlife research and conservation." Bioacoustics 30, no. 1 (2021): 41-57.

Check here for the full repository:

https://github.com/OpenWild/CaracalEvo_HW