Teensy USB Development Board
From Wildsong
I have a Teensy 3.2 USB Developmnent Board from PJRC, along with the audio adapter for it.
I have yet to fire it up. Sigh. Got it just before we moved to Cotati.
The intention was to build a device to record NFS (noctural flight calls) of migrating birds when we had our house in Corvallis.
It uses an ARM Cortex M4 processor and it costs < $20.