[kvdveer]

> How close are we to smart dust I wonder? How small can we make wireless communications?

There's two limiting factors for 'smart dust': power (batteries are the majority weight and volume of this vape), and antennae (minimum size determined by wavelength of carrier wave).

I believe you can fit an NFC module in a 5x5mm package, but that does externalize the power supply.

[cruffle_duffle]

We are going to have to rethink power for smart dust. Like consider that no creature out there is powered by batteries. From the biggest land animal to the smallest microbe it’s all chemistry.

Maybe the smart dust will have to eat microbes and stuff to stay active.

As for communication, we can’t go shoving antennas in them as then they’d be larger than dust. And you can’t use the optical part of the spectrum because of interference with basically everything. You can’t use wavelengths smaller either as you get into UV and high radiation. There is the terahertz radio spectrum [0] between 3mm and 30um that is pretty open and not utilized at all because we haven’t figured out how to make good transmitters. Plus the spectrum isn’t very useful as it isn’t very penetrating and water vapor absorbs it… and it requires lots of power.

Smart dust might have to be more of a distributed computer or something. Or a micro machine that uses chemistry and mechanical magic to do its operations.

[0] https://en.wikipedia.org/wiki/Terahertz_radiation

[TeMPOraL]

> From the biggest land animal to the smallest microbe it’s all chemistry.

Batteries are chemistry. ATP is a chemical battery.

The difference between living things and our machines is primarily in manufacturing methods: we do things in bulk, because we reach from the top with crude, meter-scale tools; nature glues things up from lots of tiny biomolecular nanomachines, and each of those tiny machines has to carry its own power source!

Still, it's highly likely that any form of "smart dust" will resemble living cells as much as, or even more so, it will resemble miniature devices we build today, simply because that's the kind of chemistry that's efficient at smaller scales.

[slow_typist]

RFID tags are powered wirelessly, one could imagine powering smaller particles when operating on higher frequencies (RFID is on 13.something MHz requiring relatively large coils). A directional antenna could send a pulsed beam to power a subset of the particles in the area and afterwards receive their signals.

[regularfry]

It needs to be in the infrared spectrum at least to be useful for smart dust, otherwise the package size is still dominated by the size of the antenna. Even mm-wave radar is marginal here.

[DANmode]

> There's two limiting factors for 'smart dust': power

RFID is historically powered by one of three methods,

one of which is completely wireless/battery-free.