Re: Glass breaks, thunderstorms and HA (was Re: Help with 7 Circuit Project?)

[Marc F Hult <MFHult@xxxxxxxxxxxxxxxxxxxxx>]

On Sat, 23 Jul 2005 09:09:19 -0400, "Robert Green"
<ROBERT_GREEN1963@xxxxxxxxx> wrote in message
<b7-dnWZ9LvjZ33_fRVn-uQ@xxxxxxx>:

>"Marc F Hult" <MFHult@xxxxxxxxxxxxxxxxxxxxx> wrote in message
>
><stuff snipped>
>
>> As long as you don't need to do numerical computations on the analog
>inputs,
>> and simply use the controller's software to detect a threshold (i.e., a
>> specific value that when exceeded triggers an effect; "IF volt > x THEN
>etc
>> ")  you can accomplish the same thing in hardware _externally_ with a
>simple
>> voltage divider formed by two fixed resistors or a pot and an opamp (or
>> transistor, comparator or TTL or CMOS digital IC) to shift the level to
>the
>> desired on/Off values (0 or 5vdc; 0 or 12vdc etc.). The usefulness of the
>> analog input depend in large part on the software/firmware of the
>> controller.
>
>If I understand you correctly, I can set up a network of directional,
>skyward pointing, weather-proof microphones, balance their output at a
>central junction box also containing a small circuit board with logic to
>trigger a relay if all microphones hear a very loud event simultaneously.
>
>While it's likely the thunder would be directional and generate large
>"pulses" from each microphone, some would be louder than others.  It would
>be interesting to mount microphones on all four corners of the roof and
feed
>them into a digital multi-track recorder and the superimpose the wave forms
>to see if they correlated with my own estimates of the direction.

That's an interesting idea too. Sound travels ~1150 feet/second so (eg) a 20
hz wave is about 56 long. So sounds from the same source reaching locations
~28 feet apart cancel. So as you suggest, I'd think you'd still need to
identify the entire 'signature' and not just compare instantaneous
amplitude.

Which is what I was referring to, namely,  using software to identify a
characteristic sound from a single microphone. Savoy's Cyberhouse's
Listen.exe can do this. There are also commercial, scientific, and freeware
programs to do this that might be adapted. Google on "sound recognition"

http://www.merl.com/projects/SoundRecognition/

As I noted previously, the sound of lightning-induced thunder is complex and
variable.

See: http://freesound.iua.upf.edu/tagsViewSingle.php?id=951

HTH ... Marc
Marc_F_Hult