I have a number of alarms in a multi-unit basement crawl space.
Smoke, CO , Explosive Gas
When a battery goes dead , it is annoying to find out which device is  
the problem.

I am looking for creative ( and cheap ) suggestions about how to make  
these tweeters distinctive.
I would be thrilled to come up with a way to report the results via  
the internet.

for example:  if I could have a different tone for each one and detect  
that, I could
use a smart ethernet adapter ( PIC based of course ) to report the  
problem.
Would different length tubes make the beeps distinctive ?

I guess I could run cheap microphones to each tweeter.

( Olin    Please don't give me another award )

Gus
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