ev_bell

Ev_bell is a software project that enables the execution of external programs upon sound events initiated by the Linux kernel. This powerful software tool has the ability to call external programs triggered by simple sound events such as the bell signal from the console. Ev_bell is designed to identify sound events on /dev/input/event*, parse them, and execute the external program immediately after.

One of the most remarkable features of Ev_bell is the ability to incorporate the event packet's fields into the argument string of the external program executed. This file is a comprehensive source code with a precompiled version for x86 computers. However, it's essential to exercise caution while using it since the creator disclaims any responsibility for any harm caused by the binary or any other binary compiled from the source, even if it doesn't run.

Ev_bell's usage is pretty straightforward: it listens to sound events on (usually /dev/input/event0) and executes the specified program by passing all remaining parameters. Such parameters might include a timestamp of the event, two long integers in decimal representation separated by a ".", the first representing the tv_sec and the second the tv_usec field of a struct timeval (seconds and microseconds since the unix epoch). Another parameter precedes the event code or sound types, with only SND_CLICK (0) and SND_BEEP (1) being specified currently. Finally, "%3" is substituted by the event value.

For example, suppose you want to execute esdplay beep.wav upon detecting a sound event on /dev/input/event0. In that case, you'd simply execute the following command: ev_bell /dev/input/event0 esdplay beep.wav.

Building this software is as easy as modifying the INSTALL_DIR in the Makefile, if you need the binary to exist elsewhere than /usr/local/bin. Then, you only run "make" and follow it up with "make install" (as root).