sub-audio pickups (not wholly OT)

[Martin Czech]

Why not use barometric pressure? Most mailorder stores carry a few
barometric sensors. Or light falling into your window?  That would make
a chaotic oscillator with about 24h cycle time ;-> Some people messure
the level of some see, or the tides. Was all done before. There are
measurement cards for PC, another good thing would be a multimeter with
RS232 interface. Hey, I have that.  Smapling time is about 1s I think,
resolution 50000 digit.  Far better then most sensors I could think of.
Maybe I should really put a phototransistor or diode or LDR into my
window for some days....  86000 samples per day, does not sound too bad.

Good idea, Paul. I thought I was running out of ideas...


Oh, I forgot: this would mean that Windooze would have to be stable
for more than 24 hours, I never dared to try that...

;->>>


m.c.



:::X-Sender: pfperry at popa.melbpc.org.au
:::Date: Wed, 25 Oct 2000 01:05:18 +1000
:::To: synth-diy at node12b53.a2000.nl
:::From: Paul Perry <pfperry at melbpc.org.au>
:::Subject: sub-audio pickups (not wholly OT)
:::
:::http://www.seismicnet.com/info/psnl96q3.txt
:::
:::is a ref to work on detecting/measuring sub audio
:::sounds in the atmosphere. (I guess where I live it would
:::mostly pick up car doors slamming).
:::
:::Over on AH people were asking, what kind of sound is there
:::below 20Hz? this is the sort of gear you would use.
:::As for actually HEARING it, if you took a sub-audio 
:::signal and ran it into a DC-coupled ring modulator, you could
:::modulate it with an audible tone & get an output that 
:::increased adn decreased as the absolute value of the sub-audio
:::waveform waxed and waned.
:::
:::Or, what I would rather do, is modulate a VCO with it.
:::Much more fun & easier to hear.
:::
:::paul perry (Frostwave analgo fx) Melbourne Australia