In 2017, Belgian researchers built a printed
plastic near-field communication (NFC) chip out
of indium, gallium, zinc and oxygen. Essential for
contactless payment systems and other proximity-
based technologies, the researchers aim to make their
chips refined enough for high-volume manufacturing
that they can be produced to the tune of around 1¢ per
square centimetre.
As similar research to manufacture IoDT devices
using inexpensive materials continues, it will further
drive the price down and make sensors available
for ever cheaper uses (and using safer, more benign
materials) – from T-shirts and bananas to skin and
body parts.
TELEMETRY
Getting the data is half the job; reporting it to a
computer or app that can make sense of it is the
other. Your ubiquitous mobile or tablet is an obvious
candidate to receive and synthesise all the new IoDT
data, but mobile phones understand GSM, UMTS
and LTE cellular signals, Wi-Fi, Bluetooth and a
handful of others.
What if your telemetry is a simple electrical
charge, a chemical reaction, a shift in air pressure or
a subtle temperature variation? Of course, we have
tools that can speak all those languages – a voltmeter,
blood sugar monitor, barometer and thermometer
respectively – but they’re not found in the average
smartphone (yet).
Until they are, designers have to resort to new
tools to listen in. One of the most popular is the
passive coil, which transmits by induction rather than
by active signalling. It sounds like double Dutch, but
in fact you’ve already used it – it’s the basis for radio
frequency ID (RFID) and NFC systems we’ve had for
many years in retail anti-theft, self-checkout and tap-
to-pay.
POWER
Putting a $1 battery on a supermarket shrink wrap
that costs less than a cent won’t just drive the price
of goods and handling unfeasibly high, it’ll be an
environmental nightmare.
In the absence of power sources that cost a fraction
of packaging, clothes or medical devices (think of
blood glucose test strips), we need to look elsewhere
- and the most likely solution at the moment seems
to be passive power.
Just as an RFID tag only comes to life when it’s in
the presence of a reader, many IoDT devices need to
extract power from their environment to work when
they’re called for and not before. And there’s no lack
of sources, from the movement of blood in a vein to
the release of gas from food, orientation to gravity
and everything in between.
Measuring calories burned during exercise is usually a matter of averages. Take
your weight, age, sex, etc and multiply according to the duration and intensity of
exercise – also called “indirect calorimetry”. But since the mid ’60s there’s been
a way of measuring the chemical content of inhaled and exhaled breaths. There’s
a lot of arcane chemistry involved, and a 2017 study found the technique “not
sufficiently accurate” to compete with indirect calorimetry, but technology has
shown us nothing if not a tendency to overcome such hurdles.03 RCP (RESPIRATORY CALORIMETER PELLET)
Since the natural home of many disposable sensors
will be the human body, it makes perfect sense to use
our heat, movement and chemistry inside – and out –
to power them. Blood pulsing past a sensor could act
like a waterfall over a turbine, and the movement of
air in and out of our lungs would nicely replicate the
operations of a mini wind farm.
A recent device developed by scientists at
France’s National Centre for Scientific Research and
the University of California, San Diego, is worn on
the skin. It flexes and stretches as the wearer moves,
producing electrical energy by oxidising the lactate
in sweat. At the moment it produces only enough
power for a single LED light, but work is being done
to amplify the voltage to power larger devices.
Then there’s 4D printing – think 3D printing,
but where the printed matter reacts further upon10mins^180PPM PPB12,0004,230cal2.01 2 143H 2 S H 2
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60 – COSMOS Issue 86TECHNOLOGY