RFID-(
ar ef i dee) -
Radio Frequency Identification (sometimes Identification
Device). A
small device which can be
contained in a
glass capsule to be placed in
pets,
carried in
cards,
worn in
clothing or a
multitude of other
places.
Used by the
US postal service (
USPS) to
track mail bags,
etc.
These devices
respond to a
low-frequency radio field from a
transmitter(usually lower than the
AM radio
band)
storing energy until they have enough to send an
id back to the transmitter. Thus they need no
batteries, and are small enough to be contained in cards just barely thicker than a
credit card, or
buttons, or inside glass capsules the size of a large
hypodermic needle.
Ford uses them in
Dearborn,
Detroit on their
employee ID cards. Many employees carry them in their
planners (or wallets), and simple pass their planners (or
shimmy their
behind-which is very
peculiar to
observe)
close to the
reader. Most RFID devices have ranges of 10-20
inches (25-50
cm) but can be
further depending on the
antenna and
transmitter configuration. Typically the RFID antenna is so small that it has to be within
several inches of the transmitter to work well, so don't get all
paranoid about it,
eh?I want to
attach one to my
watch for my
home automation system so the system can be more
intelligent.