AC hum monitoring tool.

In summary, this listens to an ALSA PCM capture interface and holds a memory
buffer. If a power event happens, this utility will automatically dump
the in-memory buffer into the disk.

The goal of this project is to learn a little more on DSP and provide a
monitoring tool for power events (flunctuation, brownout, or blackout).
Needless to say, a laptop (or other battery-powered device) should be used.

The code is in a bit of a rough shape, don't expect too much out of it.

TODO:
- Support hw: (and stereo) interfaces
- Improve algorithm (currently unusable)
  - Increase FFT window, find peak, etc...
- Do external action(s) on an event
  - ie, execute program/script in a new thread
  - $1: path to recorded event
  - $2: state (up/down)
  - $3: event type (when able...)
  - or do inline json (via stdio) with newline
- Detect brownout and flunctuation events
- Recover after sleep modes / interruptions

LICENSE: CC0 1.0 Universal
THANKS: pelp3;, cool_lantern, syncpulse

#
# Usage
#

Invoke with `--help` for usage.

First, you can to list available capture devices:
  powerwatch list

Then, use device to listen to:
  powerwatch listen --device=plughw:CARD=Generic,DEV=0 --verbose --binsize=128K

#
# Hacking
#

REQUIREMENTS:
- DUB
- A D compiler (dmd, gdc, or ldc)
- ALSA static library
  - libasound2-dev (Ubuntu)