[sdiy] Extreme DIY?

[The Old Crow]

  In 1974, on the Altair 8800 (Intel 8080 machine), there was a little 
program you could toggle in to play *the* singing computer song using 
modulated RFI made audible on an AM radio.  The idea was to use delay 
loops to access certain memory locations, and the difference 
between successive address and data switching actions (glitch noise) was 
demodulated on AM.  The carrier spectrum was quite wide, though there were 
node points on the AM dial that were strong than others. 

  The song was, of course, 'Daisy.'

  It worked pretty much interchangably on other 8080 systems, too.  I 
tried it out on an Imsai 8080 in 1977 or so.  I even got a cosmac elf 
(www.cosmacelf.com) to do it with handwritten code.

Crow
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On Wed, 20 Aug 2003, Fdi wrote:

> In the 80s, when I was about 15 years old, I  used an HP calculator as an
> impredictable  complex sound generator by calculating long sqaring roots
> with the device near the antenna of my radio. I may have some tape somewere.
> It was a delicious experience!
> Cheers,
> Fernando