savetheclocktower

Using a rotary encoder as a volume control

On my RetroPie machine I wanted a hardware volume knob — the games I play use a handful of emulators, and there's no unified software interface for controlling the volume. The speakers I got for my cabinet are great, but don't have their own hardware volume knob. So with a bunch of googling and trial and error, I figured out what I need to pull this off: a rotary encoder and a daemon that listens for the signals it sends.

Rotary encoder

A rotary encoder is like the standard potentiometer (i.e., analog volume knob) we all know, except (a) you can keep turning it in either direction for as long as you want, and thus (b) it talks to the RPi differently than a potentiometer would.

I picked up this one from Adafruit, but there are plenty others available. This rotary encoder also lets you push the knob in and treats that like a button press, so I figured that would be useful for toggling mute on and off.

graymouser

/* 
After purchasing a humble book bundle, go to your download page for that bundle. 
Open a console window for the page and paste in the below javascript
*/ 
$('a').each(function(i){
   if ($.trim($(this).text()) == 'MOBI') {
      $('body').append('<iframe id="dl_iframe_'+i+'" style="display:none;">');
      document.getElementById('dl_iframe_'+i).src = $(this).data('web');
   }
});

sr105

#! /bin/bash
# Description: show dependency tree
# Author: damphat

if [ $# -lt 1 ]; then
	echo 'Usage: apt-rdepends-tree [-r] <package>'
	echo 'Required packages: apt-rdepends'
	exit 1  
fi

damphat

#! /bin/bash
# Description: show dependency tree
# Author: damphat

if [ $# != 1 ]; then
	echo 'Usage: apt-rdepends-tree <package>'
	echo 'Required packages: apt-rdepends'
	exit 1  
fi