DIY Projects

DIY ambisonic microphone

DIY ambisonic microphone

First up is Dan Hemingson’s “ambisonic” (Wikipedia) recording work. Shown above is the tetrahedral microphone array Dan uses to record his soundscapes, three of which he played back on the ACTlab’s surround-sound system. The tetrahedral microphone arrangement makes it possible to mathematically derive any number or spatial arrangement of surround-sound channels from the raw audio. Professional ambisonic microphones cost thousands of dollars; Dan put his together for nine bucks. He played amazing recordings of a babbling river, a clowder of feeding cats, and a pipe organ recital at UT’s Bass Concert Hall, while the audience milled about the room to experience the spatial simulation of sound. The realism was absolutely uncanny.

Beautifully minimal LED Advent wreath circuit and device

Beautifully minimal LED Advent wreath circuit and device

An “Advent wreath” is a horizontal wreath, traditionally with four candles which are lit successively to mark each of the four weeks of Advent in the liturgical calendar of some western-tradition Christian churches. Alexander Weber has produced a beautiful little electronic version which uses 4 LEDs, a coin cell, a coin cell holder, a paperclip, and an 8-bit microcontroller chip. It is light-responsive, and uses one of the LEDs in “reverse” mode as a photodiode to detect darkness. The LEDs flicker, and the number of LEDs lit at any point is cycled by briefly cutting the power. Awesome design.

Holding round-head screws for trimming

Holding round-head screws for trimming

Neil sent me this link to a cool trick for holding round-head screws while you cut the threads shorter. Cut a thin slit in a correspondingly-threaded nut, through one of the points. A rotary tool with an abrasive disk is probably a good tool for this. Then you can thread the screw in and grip the nut across the flats with pliers or a vise. Compression across the width of the slit will hold the screw firmly in place, and you can use the flat side of the nut to guide the saw.