- Much has been said about the miracle abilities of
chip technology. It is widely claimed to track people and items, and it's
time to set the record straight. As someone who has designed and built
miniature transmitters, I can tell you there are many exaggerations about
this technology. I'll leave the tech talk out of this as much as possible
to make it more readable.
- There are basically 3 types of technologies:
- 1. PASSIVE - These are found in rental tape labels
Kind Please Rewind") and other similar labels. Also, a small strip
inserted into the spine of a library book operates the same way. These
are activated and deactivated with a powerful magnet on the checkout
All of these function by using a resonant circuit to operate at one
radio frequency. When this type of label passes through a portal's radio
frequency field, a sensitive receiver connected to the portal detects the
resonance of a particular label and sounds the alarm. Since these receivers
are very sensitive, and sometimes other unrelated objects can trip the
alarm, too. These devices do NOT have any ID chips, and are intended only
as an alarm to detect an object of value being removed from a given area.
These are also used inside the white plastic clips used in stores to
shoplifting, as well as inside the packages of some products. This is also
similar to the strip found embedded in today's currency.
- Range - There is no real range to this type of RFID
other than inside a portal or near a wand that can power it and read it.
This device cannot transmit any signals on it's own, contrary to public
- 2. SEMI-PASSIVE - These are the type of interest to
and others. This consists of a small chip connected to an antenna. The
simple chip contains a simple power rectification circuit, a few bytes
of memory to store a serial number and very small transmitter circuit.
This is also the same type used in the implantable chips for humans and
animals. The chip is powered by an external field such as a wand or a
Once powered up by receiving energy from the small antenna (such as the
tiny coil inside the Digital Angel device) the transmitter circuit operates
and transmits the serial number. A receiver detects the signal from the
device and sends the data to a computer. Don't be fooled by press release
pictures from Hitachi and other companies that show how tiny the chip is.
A antenna is always required for it to work - which is hundreds of times
larger than the chip.
- Range - As these devices can only use a very small
of the RF energy from the field that powers them, and distance is limited
to a few feet. It is virtually impossible for someone at the street to
point an antenna at your home and detect an RFID device. The reason: radio
frequency energy falls off the square of the distance in BOTH directions,
just like light from a flashlight. This also includes the RF power used
to power the device. Power transmitted from the device is measured in
or less which therefore limits range. Data collision is a problem, too.
This occurs when more than one device attempts to transmit it's data at
the same time. It is one of the engineering problems being worked on for
the proposed shopping portals in stores. When fully implemented, you will
wheel your shopping cart through past a portal and it will automatically
read all the items in the cart.
- 3. ACTIVE - This is where RFID becomes seriously
This consists of systems such as Northstar and similar "help"
systems used in vehicles, and covert hidden technology used in cordless,
speakerphones and cell phones. This was illustrated in the film "Enemy
of the State." Most of the technology shown in the film is real or
is possible. Active technology far surpasses transmitting only serial
- these devices can be silently activated by intelligence agencies via
satellite command signals. Not only can agencies determine where you are
on the globe, but they can also to listen in on your conversations at will.
The movie was wrong about flushing a tracking device and showing it still
working. Even if it survives immersion in water, it will quickly become
undetectable. This is caused by the shielding of the water, the metal
of the sewer pipe and/or earth around the pipe even if made of PVC. Active
technology requires use of a battery or other power source to transmit
with sufficient power over distance. This is also why it works so well
with cordless and cell phones. People should be more concerned about the
current use of this technology in vehicles and telephones. Rather than
passive or semi-passive devices described above which are much more limited
and cannot eavesdrop.
- Personally, I don't support any spying or surveillance
of people. This always leads to a paranoid state of mind, like that endured
by the people of East Germany for decades. But with this new technology
- it has the potential to be far worse than anything the Stasi organization
imagined and it will be far more invasive.
- Tracking people and objects clearly implies mistrust,
and has little or nothing to with preventing terrorism.