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contains sensors, computational ability, bi-directional wireless communications, and a
power supply, while being inexpensive enough to deploy by the hundreds (see Figure
2.18). This kind of device is possible to build using state-of the-art technologies, but will
require evolutionary and revolutionary advances in integration, miniaturization, and
energy management. 8
Figure 2.18 “Smart Dust: Communicating with a cubic-millimeter computer”:
http://ieeexplore.ieee.org/iel5/2/19363/00895117.pdf?arnumber=895117
The advantages of this kind of device are: portability, autonomy, and small size for an
exponentially decreasing cost. The goal is to use them in places that humans cannot go
(e.g. in contaminated sites), and to allow continuous detection in strategic locations (e.g.
airports). They can serve as sensors for biological, chemical or radioactive agents.
Nanotechnologies will not bring huge advancements in terms of miniaturization because
the development of Micro Electro Mechanical Systems (MEMS) has already achieved this.
The sensor component will use technology described in previous sections, however for
smart dust to be successful will require advances in the fields of power (energy
scavenging, generation, storage) and data (transmission, processing) management.
2.4.1 Power management
The power system may consist of a battery (essentially lithium ion or nickel metal
hydride) and/or a solar cell with a charge integrating capacitor for periods of darkness.
Other power systems are under study principally in the field of energy scavenging, e.g.
using vibration to generate power.
Batteries
The lifetime and efficiency of charging and discharging cycles in batteries is critically
dependent on storage and/or the intercalation properties of the anode material. Carbon
nanotubes can provide an alternative to current anode fabrication technology (based on
graphite). CNT anodic layers around metal cathodes, such as Cu, are under investigation
as well as Li and K intercalation in SWCNT bundles and/or MWCNT. Other experiments
report increasing reversible charge capacity by a 600% by introducing nanoparticles of
cobalt nickel and ferric oxides in the electrode material of lithium ion batteries (Poizot et
8 http://www-bsac.eecs.berkeley.edu/archive/users/warneke-brett/SmartDust/
18