A
Al
Many, many years ago I built a little circuit from my much-loved copy of
Forrest Mims Engineer's notebook. It was based on 555/556 timers, and had
a couple of pots on it which when twiddled caused the thing to generate some
pretty spaced out sound effects. Recently, I remembered this great little
device and decided to make one again. Can I find the book?! I turned my
house and my parents house inside out, no luck :-(
I thought I'd stumbled across the very circuit on the net:
http://www.jesush.com/peasej/archives/000422.php
This looked like it was it! However, after building it I'm not so sure this
was the circuit after all. This one just adjusts the frequency of the main
oscillator with another oscillator, giving police siren or vibrato type
noises. As you tweak one pot the main frequency varies, tweaking the other
pot alters the modulating frequency.
From memory (bearing in mind it was around 20 years ago) the project I built
just emmitted a single continuous tone when the pots weren't touched. But
while you were actually twiddling them it made all sorts of crazy whooping
noises, which changed depending on direction and speed that you turned the
pots. Fantastic!
Here's where I start asking favours. If anyone's got a copy of the book to
hand (in the UK it was an A4 sized yellow paper back, from Tandy
(RadioShack)), would they mind just looking through it, and putting me out
of my mysery - is there another sound-effects generator circuit, not the
above one, that possible uses a couple of 556 dual timers?
Just knowing whether or not my memory is playing tricks on me or not would
encourage me to search harder for the book, but (and here's the really
cheeky bit) if anyone out there is feeling really kind, perhaps they'd care
to scan in the schematic and email it to me?
That book was great by the way. What reminded me of the whole thing in the
first place was finding the 10x10 LED array oscilloscope that I built from
the book. Not the most useful bit of test gear in the world, but it really
did work! I really want to find my copy again. I did look on Amazon but
it's a bit expensive as it only seems to be available on import from US.
Anyway, thanks for your time!
al
*********************************************
[email protected]
To reply, just take the upper case
SPAM out of both parts of the address
**********************************************
Forrest Mims Engineer's notebook. It was based on 555/556 timers, and had
a couple of pots on it which when twiddled caused the thing to generate some
pretty spaced out sound effects. Recently, I remembered this great little
device and decided to make one again. Can I find the book?! I turned my
house and my parents house inside out, no luck :-(
I thought I'd stumbled across the very circuit on the net:
http://www.jesush.com/peasej/archives/000422.php
This looked like it was it! However, after building it I'm not so sure this
was the circuit after all. This one just adjusts the frequency of the main
oscillator with another oscillator, giving police siren or vibrato type
noises. As you tweak one pot the main frequency varies, tweaking the other
pot alters the modulating frequency.
From memory (bearing in mind it was around 20 years ago) the project I built
just emmitted a single continuous tone when the pots weren't touched. But
while you were actually twiddling them it made all sorts of crazy whooping
noises, which changed depending on direction and speed that you turned the
pots. Fantastic!
Here's where I start asking favours. If anyone's got a copy of the book to
hand (in the UK it was an A4 sized yellow paper back, from Tandy
(RadioShack)), would they mind just looking through it, and putting me out
of my mysery - is there another sound-effects generator circuit, not the
above one, that possible uses a couple of 556 dual timers?
Just knowing whether or not my memory is playing tricks on me or not would
encourage me to search harder for the book, but (and here's the really
cheeky bit) if anyone out there is feeling really kind, perhaps they'd care
to scan in the schematic and email it to me?
That book was great by the way. What reminded me of the whole thing in the
first place was finding the 10x10 LED array oscilloscope that I built from
the book. Not the most useful bit of test gear in the world, but it really
did work! I really want to find my copy again. I did look on Amazon but
it's a bit expensive as it only seems to be available on import from US.
Anyway, thanks for your time!
al
*********************************************
[email protected]
To reply, just take the upper case
SPAM out of both parts of the address
**********************************************
