Build an Airplay Receiver Using Raspberry Pi

If you’re like me, you have tons of music on your computer but usually end up listening to it on headphones. If you want to use real speakers, you either run an audio cable to your stereo (tripping hazard, low-quality sound) or drag out an audio interface ($$, lots of cables). Bluetooth is an option, but the sound quality is ok at best. Apple’s Airplay goes over wifi and gives much higher-quality audio, but you’ll need some way to get that signal to your receiver or amplifier. There are lots of options on the market, but if you have a Raspberry Pi lying around, it makes a great and very cheap solution!

I decided to use the HDMI out for audio, which gives way better quality, and to include a power button and LED inside a nice laser-cut case. So far, it’s worked great for music as well as movies and podcasts!

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Acoustic Locator



Really want to build one of these on the Stevens campus: acoustic locator devices from the 1920s and 30s, built to help detect incoming aircraft.

Racal MA-4204 Time Division Voice Scrambler


Another device using random acoustic noise for cryptographic purposes. This device from the early 1970s randomly rearranges the audio signal every half-second; a corresponding unit puts the audio back in the correct order on the other end. While not very secure (the three 8-position switches only provide 512 possible combinations), this device’s operation and style have a nice mix of of functionality and poetics.

Via Cryptography Museum.

Antiaircraft Sound Locator


An acoustical device used before the invention of radar to detect incoming planes by sound. The stereo horns ran right into the operators ears, like gigantic headphones. To the right is a spotlight for nighttime operation.

Via Wikipedia

Long-String Guitar Documentation


Documentation of the long-string guitar, a single-string electric instrument designed using extruded aluminum beams to be completely adjustable and customizable.

Above, the bridge section, which is attached to the wall using aluminum brackets. The string is attached to an eyebolt, then across a lasercut acrylic bridge and over a humbucker pickup. The electronics include a tone knob and 1/4″ output. The pickup is not soldered to the electronics but connected with a terminal block, making it easy to swap different pickups.

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Door “Oof” In Doom And Thoughts On UX Design

When the PC game “Doom” came out in 1993, my dad brought a copy home from work. I don’t think he realized how violent and full of satanic imagery the game was (to my happy surprise) and I spent way too many hours playing the game. Not having much access to videogames as a kid, Doom and a few others (Super Mario Brothers for NES, Tetris on the original Game Boy, Sonic the Hedgehog, Mattel Football, Pitfall for Intellivision) remain my reference points when I think about games.

Early experiments toward a series of haptic and non-visual games have led to a realization: a single type of feedback in a game generally results in a flat, non-immersive experience. An animation of a gun firing with no gunshot sound is still believable and playable, but with that extra feedback of the gunshot sound the game becomes realistic, and we suspend disbelief and fall into the game. But another type of feedback has struck me as deeper, effecting not just the enjoyment of a game but actually driving the UX design and clarity of the gamespace and its rules.

A case study can be found in Doom: in the game there are two types of doors, ones that you can open any time and ones that require keys (picked up elsewhere in the level). Upon reaching a door of either type, the player presses a key on the keyboard to try to open the door. If you have the key or the door doesn’t require one, it opens with a satisfying “swoosh” – like a gunshot, this sound adds to our immersive experience. However, when the player attempts to open a door without the proper key, nothing happens visually but the character emits a loud “OOF!” sound.

The “oof” is key: without it nothing would happen at all and we would be left wondering “did I press the right key on the keyboard? Is this a door at all?” The above videos demonstrate this in the game – the first is normal gameplay, the second with the sound modified so there is no “oof”. While this translates in video, actual gameplay is really required to fully appreciate the difference a single sound effect can make on an interaction.

This question originally arose while developing the badge for the 2012 Games++ event, where the only feedback for navigating a dungeon space was a vibrating motor. With each tile-type (sand, stone, etc) as a unique vibration pattern, the question became: what about walls? Should there be a vibration when you can’t move in a particular direction? What does no vibration signify? We decided on no vibration, which gives the added possibility that someone might invert the level in their mind’s eye, seeing walls as pathways and other tiles as walls.

Curiosity Rover Animation

This 11-minute animation from NASA shows the Curiosity rover landing on and traversing across Mars.  It is nearly silent, save some realistic but oddly empty foley sound, making the rover seem very much alone.