[oclug] RFID water readings

[Rod Giffin]

Quoting Brad Barnett <lists at l8r.net>:

> On Wed, 16 Aug 2006 16:19:32 -0400
> Rod Giffin <rgiffin at xplornet.com> wrote:
> 
> > Quoting miden <miden at travel-net.com>:
> > 
> > > the meter directly. Radio metering would be welcomed by him/her
> I'm
> > > sure. Power for the unit? How about Solar? My calculator has
> been
> > > running on a little solar cell (under room lights) for many
> years.
> > > Can't
> > > require much more power than that.
> > 
> > Power requirement for RFID devices is very very low.  In fact, they
> 
> > usually work without any external electrical connection, instead,
> they 
> > can use power extracted from the radio signal from the reader
> itself, 
> > and they've been developing RFID devices for the oil & gas industry
> 
> > for a while.
> > 
> 
> 
> Sure, but that's not going to be very effective if you're reading
> from
> 100M away... or 20M away, but through a house.
> 
> We don't want a nuclear level EMP sent out, just to read the gas
> meter at
> each house! ;)

Try *450 feet at 500 micro Watts. (*Mfg's claim)  And you know that 
Satellite and cell phone signals can penetrate a building made of 
concrete and steel with a fraction of that power.  It's a function of 
the RFID reader's sensitivity, not a function of the RFID device.  
With this technology, it would also be a trivial exercise to mount the 
RFID device on the front of the house.  It's not like we're looking at 
huge devices here.  The actual RFID device itself is about the size of 
a grain of rice.

Rod.