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■ BY LOUIS E. FRENZEL
SHORT-RANGE
WIRELESS EXPLOSION
Cypress Semiconductor’s Wireless USB
chips are a popular but non-standard
wireless method for short range
applications like computer peripherals,
consumer products, and industrial
monitoring and control. It is an
alternative to ZigBee, Bluetooth, and
ISM radios. It operates in the 2.4 GHz
band and has a data rate of 62. 5 kbps.
WIRELESS EVERYTHING. If it seems like you are hearing and
seeing more about wireless devices every day, it’s not just
your imagination. Over the past few years, there has been a
virtual explosion of new wireless devices and services. And I
am not just talking about our cell phones which have become
our all-purpose, go anywhere, do everything communicating
Swiss Army knife equivalents. There really has been a premeditated effort to make anything and everything wireless.
Of course, we have had wireless
devices for decades. Our TV,
VCR/DVD, stereo remote controls are
the main example. But garage door
openers have also been around for
years. Cordless phones now account for
the majority of home phones sold. More
recently, almost every new car has a
remote keyless entry feature. Wireless
toy cars and remote controlled planes
and boats have been around for years,
too. But today, wireless is replacing
cables and showing up in lots of unexpected places. Thanks to a bundle of
new wireless standards and cheap radio
chipsets, it is possible to incorporate a
wireless feature into almost anything.
Wireless is clearly addictive as it
makes things more convenient. No
one wants to fuss with a cable.
Besides, we appreciate the freedom of
mobility. Wireless liberates us from
our tethered past.
Here is an overview to familiarize
you with the current hot wireless
technologies.
BLUETOOTH
Bluetooth was originally developed
by Ericsson — the Swedish cell phone
company — as a cable replacement
between a headset and a cell phone.
20 February 2006
When I first heard of this I asked how
much of a problem could a short, three-foot cable between a cell phone and the
headset be? Does it really make sense to
replace a 25 cent cable with a complicated digital microwave two-way radio?
The answer turned out to be a big yes.
Now nearly 50% of all cell phones contain a Bluetooth transceiver that communicates with a companion headset. It
is a common sight these days to see a
person talking on a wireless headset.
They even make a version for hands-free
operation of a cell phone in a car.
When you put an electronic part in
a cell phone, you generate horrendous
volume. Over 800 million cell phones
were sold last year and if almost half of
them contain a Bluetooth chip, that’s
big volume. Over 500 million
Bluetooth chips were sold to date and
the ship rate has now increased to
nearly 10 million a week. Most of these
go into cell phones, of course, but
there are many other uses, as well.
When a chip achieves that volume,
it means that the price drops to a very
low level. Today, a Bluetooth chip sells
for less than $5. That makes it attractive for other applications. Other common uses are wireless links between a
laptop and a cell phone for Internet
access. Bluetooth chips also show up
in wireless computer interfaces like
keyboards, mice, and printers. No need
to buy, string, or worry about a cable.
Bluetooth is a radio standard
developed and blessed by the
Bluetooth Special Interest Group (SIG).
They promote the standard and develop new applications called Profiles.
The SIG also conducts testing and certification to ensure that all Bluetooth
products interoperate with one another. This ensures that the Bluetooth
product from one manufacturer talks to
that of any other manufacturer.
Bluetooth operates in the 2.4 GHz
unlicensed Part 15 FCC band. It uses
frequency hopping spread spectrum
with FSK modulation. It is a digital
radio with a maximum data rate of
1 Mb/s. A new version 2.0 of the
standard is called Enhanced Data
Rate (EDR) and transmits data at up
to 3 Mb/s. The transmission range is
about 10 meters max, depending
upon the environment. A higher
power version can also be used to
achieve a range up to 100 meters with
clear line-of-sight between antennas.
One of the key features of
Bluetooth is its ability to automatically
link up with other nearby Bluetooth
devices to form what is called a piconet.
One Bluetooth transceiver acts as a
