June
2000, Issue 119
The
Chips are Alive with the Sound of Music
Imitatiing
the Dead Melody IC
by
Jeff Bachiochi
The
Von Trapp family may have made some great music, but
try fitting them all into a birthday card and you’ll
see why Holtek’s Melody Generator ICs were such
a hit.
I
used to make an annual pilgrimage to New Jersey for
the Trenton Computer Fair. It wasn’t like today’s
computer fairs where John Q Public roams the aisles
for the cheapest Taiwanese clones. Most of the products
were made by hand for the elite who knew what a computer
was before Macintosh and Microsoft.
Outside,
hackers (back when a hacker was a good guy) and hams
sold the electronic stuff that had been collecting dust
since they bought it the previous year. I picked up
the first singing birthday card I ever saw at a fair.
"Wow," I thought, "How did they get all
that into a card?" I plunked down five bucks and
ogled at the little bits inside the folded paper greeting.
I
had to search high and low for an old Digikey catalog.
I learned not to throw out an old databook when the
new one arrives, but didn’t think I’d need
an old Digikey catalog. However, I knew I had seen these
things in there, the Holtek Melody Generator ICs, a
TO-92 device with connections for a battery and a piezo
output device (see Figure 1). They cost less than $1
and were available in a selection of melodies. But,
Digikey no longer lists them. A trip to Holtek’s
web site confirmed my fears that they were discontinued.
|
|
| Figure 1-Holtek
melody generators were popular, but they have since
been discontinued. |
