> 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.

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slow_typist 2 hours ago | parent [-]

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 an hour ago \| parent [-]
		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.