Digital fluids, smart make-up, liquid computing and cloud nets
A long time ago it occurred to me that if ink contained small particles that could hold digital information, a signature by pen on paper could act as a digital signature, too.
There are lots of ways that particles small enough to be suspended in ink can hold data. But data storage is only one of several different potential uses.The most obvious data storage form is chemical storage or tagging. For example, smart water has been around for ages, with chemicals in it of known unique origin - each batch made has a different signature so that anything it is sprayed on is marked with its specific data.
Looking at nature, blood is billions of years old and contains cells with lots of DNA, which can certainly be used as a digital storage medium. So perhaps blood is the original digital fluid.
Alternatively, electronic data storage could be used, with tiny memory chips, or even miniature RFID chips that could be programmed as they leave the pen.
RFID chips are too big so far and their antennae are designed to work at frequencies that need larger size, but the RFID concept is flexible and high frequencies or optical programming could be used instead. It wouldn't still be called RFID if it isn't using radio, but the rest of the functionality could remain.
Electronic ink (kindle type displays for example) could be considered also a digital fluid, containing particles with changeable orientation to show black or white, though that stretches the category a little. Stretching it even more, liquid crystals are switchable so also offer primitive digital functionality.
Smart make-up would be an interesting development. In the simplest implementation particles in it could be made to align with an electric or magnetic field generated by a printed substrate. Slightly more advanced, electronic particles of make-up could self organise into the image chosen. Thereafter they could stay that way until instructed, locally or via the net, or follow some standalone algorithm for image change.
This would allow them to be used as video make-up, smart tattoos, security patterns and various other uses. Particles in it could also transmit digital auras to external equipment, enabling multiple avatar overlays. This would blur the line between virtual and real imagery.
Apart from data storage and particle alignment uses, digital fluids could also carry a suspension of sensor particles. These could be any kind of sensor that can be made small enough, (some may need encapsulation too, which also adds size). Building on the smart water concept, this would be produced in similar ways, and perhaps sometimes even deployed in similar ways.
The sensors in the water would gather data and store it electronically or chemically. The data could be read by equipment on demand. If it is sprayed onto walls, roads or street furniture by street cleaner vehicles, it could gather a lot of environmental data which could be read by devices on any passing vehicle or person, or routed via a self organising cloud network.
That brings us nicely to another use - networking, using fluids that can incorporate myriad tiny particles that can self organise into networks. Again, these could be sprayed onto any surface. Self organisation is a very powerful technique, biomimetically inspired, almost biokleptic.
Yet another use is holding processing particles, providing another self organising component of the smart chips-everywhere cloud. Processors networked with sensors and storage makes a nice mix for simple physics-based process allocation algorithms that would be far faster and more robust than schedulers in current operating systems. Digital fluids eventually could be computing by the litre.
And finally, fluids could hold actuator particles that can do a wide range of physical things, contracting or expanding, changing viscosity, absorbing light or radiation, changing colour, vibrating, creating a temperature or chemical gradient...
A smart fluid could of course incorporate a mix of all of the above. It could be very smart. With its own embedded data, a wide range of self organised sensor capability, processing and networking, and even the ability to form some sort of display, added to mechanical, electrical magnetic or chemical actuation, it could be a very powerful tool-kit. We should therefore expect a growing industry around the field of digital fluids.