Alex Meub meub

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.

Launch Sublime Text 2 from the Mac OS X Terminal

Sublime Text 2 ships with a CLI called subl (why not "sublime", go figure). This utility is hidden in the following folder (assuming you installed Sublime in /Applications like normal folk. If this following line opens Sublime Text for you, then bingo, you're ready.

open /Applications/Sublime\ Text\ 2.app/Contents/SharedSupport/bin/subl

You can find more (official) details about subl here: http://www.sublimetext.com/docs/2/osx_command_line.html

Installation

Launch Sublime Text 2 from the Mac OS X Terminal

Sublime Text 2 ships with a CLI called subl (why not "sublime", go figure). This utility is hidden in the following folder (assuming you installed Sublime in /Applications like normal folk. If this following line opens Sublime Text for you, then bingo, you're ready.

open /Applications/Sublime\ Text\ 2.app/Contents/SharedSupport/bin/subl

You can find more (official) details about subl here: http://www.sublimetext.com/docs/2/osx_command_line.html

	#!/usr/bin/env python

	import math
	import sys
	from moviepy.editor import AudioClip, VideoFileClip, concatenate_videoclips



	# Get average RGB of part of a frame. Frame is H * W * 3 (rgb)
	# Assumes x1 < x2, y1 < y2

	# -- coding:utf-8 --
	'''
	Simplistic script to parse the detailed AWS billing CSV file.

	Script displays cost of S3 operations broken down per region, bucket and usage
	type (either storage or network). It also sums up the amount of storage used per bucket.
	Output is filtered wrt to costs < 1$.

	See http://docs.aws.amazon.com/awsaccountbilling/latest/about/programaccess.html for
	how to set up programmatic access to your billing.

	import socket
	import sys
	import threading
	import queue
	import time

	common_ports = {
	"21": "FTP",
	"22": "SSH",
	"23": "Telnet",

	# Released by rdb under the Unlicense (unlicense.org)
	# Based on information from:
	# https://www.kernel.org/doc/Documentation/input/joystick-api.txt

	import os, struct, array
	from fcntl import ioctl

	# Iterate over the joystick devices.
	print('Available devices:')

	# -- coding:utf-8 --
	'''
	Simplistic script to parse the detailed AWS billing CSV file.

	Script displays cost of S3 operations broken down per region, bucket and usage
	type (either storage or network). It also sums up the amount of storage used per bucket.
	Output is filtered wrt to costs < 1$.

	See http://docs.aws.amazon.com/awsaccountbilling/latest/about/programaccess.html for
	how to set up programmatic access to your billing.

	import random as r
	import math as m

	# Number of darts that land inside.
	inside = 0
	# Total number of darts to throw.
	total = 1000

	# Iterate for the number of darts.
	for i in range(0, total):