[LAU] Re: [linux-audio-user] Create high-pitch noises like the mosquito device

[Ken Restivo]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On Tue, Apr 03, 2007 at 03:58:48PM +0200, Robin Gareus wrote:
> 
> 
> listreader wrote:
> > Robin Gareus wrote:
> >> listreader wrote:
> >>> [..]
> >>> Whats good software in linux to generate certain frequencies?
> >>
> >> judging from your motivation I can't say if it's /good software/, but
> >> "xmms" is avail. for many linux-distros:
> >> [..]
> > 
> > My motivation?!  What?  I didn't say anything about why I wanted to copy
> > that device.  I think it's a cool exercise.
> 
> sorry, if my comment was a ambiguous. If you've got some more time to
> exercise, it's easy to do a hardware implementation - it's called
> "astable multivibrator" take a battery, two Transistors a Cap and few
> Resistors,... - eg. http://en.wikipedia.org/wiki/Multivibrator - for a
> more professional approach, follow the NE555 IC idea. radio-shack sells
> those..
> 

I had good luck using Schmidt triggers to make quick-and-dirty square-wave oscillators for testing purposes:

http://en.wikipedia.org/wiki/Schmitt_trigger

Very cheap and simple: one chip, a resistor, and a cap, IIRC.

- -ken
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.1 (GNU/Linux)

iD8DBQFGEouwe8HF+6xeOIcRAsADAJwILYYa9uERy/0n1/kgalvYEjGNqACgsjKO
C2MoE5zS9BXqk1NLGoXScVw=
=2M/c
-----END PGP SIGNATURE-----