Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!usc!brutus.cs.uiuc.edu!ux1.cso.uiuc.edu!ux1.cso.uiuc.edu!m.cs.uiuc.edu!irwin
From: irwin@m.cs.uiuc.edu
Newsgroups: sci.electronics
Subject: Re: power from phone line
Message-ID: <21000051@m.cs.uiuc.edu>
Date: 28 Dec 89 01:38:45 GMT
References: <14230@jumbo.dec.com>
Lines: 57
Nf-ID: #R:jumbo.dec.com:14230:m.cs.uiuc.edu:21000051:000:2669
Nf-From: m.cs.uiuc.edu!irwin    Dec 27 15:45:00 1989


/* Written 10:21 pm  Dec  4, 1989 by murray@jumbo.dec.com in m.cs.uiuc.edu:sci.electronics */
/* ---------- "power from phone line" ---------- */
>Suppose you have some remote instrumentation, like a seismometer, 
>or weather station, and you are transmitting that data back to a 
>central collection point via a phone line.

>Can you scrounge any power from the phone line? I'm not thinking of 
>many watts, just enough to run a few slow CMOS chips.

>Is there an obvious book I should know about that answers things like 
>this?
/* End of text from m.cs.uiuc.edu:sci.electronics */

A few years a go, the University of Illinois was doing some research
on tracking wild animals, in Northern U.S. and in Canada. They would
locate them by aircraft, fly low over them, shoot them with a stun
gun dart, then land in a clearing, hike back and tab the animal with
an ear tag. They also mounted a collar with a radio transmitter on
it.

They had phone pairs ran up to the top of high ground, spaced some
50 miles apart. Connected to the phone pair was an RCA 1802 CMOS
microprocessor, with ROM, RAM and a few CMOS radio receivers. They
put the transmitters on various frequencies, based on the type of
animal. A Bear was on one frequency, Elk on another, Moose on another,
Deer on another, etc.

During idle time, the RAM and radio receivers were powered down, just
a minimum amount of circutry was active. This would allow the phone
pair to recharge the nicads. When they called the phone pair, it would
activate the 1802, with the small amount of ROM and stack memory, they
would tell the 1802 to output to an I/O port, which would enable the
main RAM and they would then download software to it. They could then
with the software in RAM, activate various I/O port configurations,
which would enable a given receiver. If the receiver was receiving
a signal, they would know that Mr. Bear was within radio distance,
if he wasn't, they would disable that receiver and go on to the next
one.

With a grid of phone/microprocessor stations, they could track the
animals. By finding which stations were receiving a given frequency,
they could plot a vector to figure quite closely where they were.

Though I was not involved with this, I know the person who was, that
built the hardware and wrote the software for the project. He even
went into the "wilds" on a few occasions, to help with the stations
being set up and bagging the animals to tag/collar them. He still
lives locally and I could put anyone in contact with him that might
desire to talk with him via phone.

Me, I thought it was a very neat project.

Al Irwin
Univ of Illinois
Dept of Comp Sci
irwin@m.cs.uiuc.edu