Circuit bending is the art of creatively short circuiting low voltage hardware to create interesting and unexpected results. It’s generally applied to things like Furbys, old Casio keyboards, or early consoles to create audio and video glitches for artistic effect. It’s often practiced with a random approach, but by bringing in a little knowledge, you can get astounding results. [r20029] decided to apply her knowledge of CD players and RAM to create this glitched out Sony Discman.
Portable CD players face the difficult problem of vibration and shocks causing the laser to skip tracks on the disc, leading to annoying stutters in audio playback. To get around this, better models feature a RAM chip acting as a buffer that allows the player to read ahead. The audio is played from the RAM, giving the laser time to find its track again and refill the buffer when shocks occur. As long as the laser can get back on track fast enough before the buffer runs out, the listener won’t hear any audible disturbances.
[r20029] soldered wires to the leads of the RAM chip, and broke everything out into banana jacks to create a patch bay for experimenting. By shorting the various leads of the chip, this allows both data and addressing of the RAM to be manipulated. This can lead to audio samples being played back out of sync, samples being mashed up with addresses, and all manner of other weird combinations. This jumbled, disordered playback of damaged samples is what creates the glitchy sounds desired. [r20029] notes that certain connections on the patchbay will cause playback to freeze. Turning the anti-skip feature off and back on will allow playback to resume.
The write up highlights the basic methodology of the hack if you wish to replicate it – simply find the anti-skip RAM on your own CD player by looking for address lines, and break out the pins to a patch bay yourself. This should be possible on most modern CD players with antiskip functionality; it would be interesting to see it in action on a model that can also play back MP3 files from a data CD.
Circuit bending is a fun and safe way to get into electronics, and you can learn a lot along the way. Check out our Intro to Circuit Bending to get yourself started.