Robot voice changer kit found

[Byron Jacquot]

>"...this device allows you to adjust three major sound factors: VCO, VCF, 
>and VCA.  Four pushbutton controls give you the option to add 
>vibrat., raise or lower your voice seven tones (seven up or down) or 
>to sound like a robot."
>
>I don't know what they mean by the VCO, VCF, VCA; I seriously doubt 
>that this kit is actually a VCO, VCF, and VCA, but for $9.95, it's 
>worth a shot... the main IC on the board looks like a "MT8950A", any 
>one heard of it?

The IC is the Holtek Ht8950.  There is more info about the part at
www.holtek.com.  Their site is down right now, but the chip should be listed
with the other musical toy chips.

The description from the catalog is a little misleading, as it doesnt have a
VCO, VCF or VCA.  From that I can tell, it's a set of A/D and D/A
converters, with a bit of RAM in between.  The rate at which the RAM is read
back and played can differ from the rate at which new samples are written,
for pitch shifting FX.  I'm not exactly certain how the Robot mode is created.

I built one of that exact kit last fall, and since then I've wired up
several more perfboard circuits around the 8950.  The kit comes nearly
verbatim from the data sheet.  There was also an article in ETI sometime in
the last year covering it.

For the money, they're fun little devices.  Not exactly an Eventide for
pitch shifting, but still a lot of fun...good for drum machines, too!  I've
got some samples of one on a spartan page at
http://w3.uwyo.edu/~thescum/changer.html

Byron