Chemical "Infofuses" Communicate Without Electricity

Al writes "Researchers at Harvard and Tufts University have developed a way to send coded messages without using electricity. David Walt, professor of chemistry at Tufts, and Harvard's George Whitesides have developed 'infofuses' that can transmit information simply by burning. The fuses — metallic salts depositing on a nitrocellulose strand — emit pulses of infrared and visible light of different colors whose sequence encodes information. They were developed in response to a call from the Defense Advanced Research Projects Agency for technologies to allow soldiers stranded without a power source to communicate. In the first demonstration of the idea, they used the infofuses to transmit the message look mom no electricity." Currently the researchers are "trying to figure out a way to dynamically encode a message on the fly in the field without specialized equipment."

GI Joseph and the Amazing Technicolor Smoke Signal

[Red Flayer]

Smoke signals... in color.

Morse code... without electricity.

In order to communicate effectively without electricity, it makes sense to look back to the time before electricity.

As for coding-messages-on-the-fly for the flare o' many colors, what kind of data density are they looking for? Wafers of colored fuel could be dropped into a tube that is then sealed for burning.

Or, they could just figure out a way to send morse code with a flare... maybe some kind of retractable hood to be used as an interrupt?

Sent message "x"

[noidentity]

In the first demonstration of the idea, they used the infofuses to transmit the message "look mom no electricity".

Said message could be sent with a single flash [wikipedia.org], if that's the only message they might send. The question is how many other possible messages they could have sent. For example, if they sent this as 7-bit ASCII, it'd be more impressive, though some kind of Huffman encoding [wikipedia.org] would be most appropriate.

Extra battery?

[archer, the]

Which would you rather add to your pack? A pound of flammable material, or a half-pound radio/battery with a half-pound hand-cranked generator?

Re:Tarps, flags, semaphore, mirrors....

[fooslacker]

Maybe I'm feeding the trolls but perhaps the key is that it's not a giant flag telling the enemy where you are down behind enemy lines. Maybe the fact that it's IR and can be activated when you hear your rescue run coming could have something to do with the fact that DARPA finds value in it.

Re:Can't they...

[Bill, Shooter of Bul]

Using existing technologies in existing ways is not research. Using new technologies in existing ways is. I'm a big supporter of research for the sake of research and science for the sake of science. Would you really have wanted DARPA to cancel the arpnet, because the application they had in mind assumed the use of nuclear weapons?

Note: I think that may or may not be the case that the arpnet was sold as a means for communications to survive in the event of a nuclear strike. but anyway you get the point I'm trying to make. Sometimes the craziest, least practical seeming research results in the coolest stuff.

Re:hand cranked flashlight

[sortius_nod]

This is the same thing I was thinking of. Is it really any use as the receiver needs to have at least a camera and laptop, or some specialised decoder device to even make this usable.

While the technology seems neat, it also seems a bit more like a weekend project of someone with an inkjet printer and some chemicals. Did it really require funding from DARPA? I'd hazard a guess and say "no".

Re:hand cranked flashlight

[TubeSteak]

It's odd that the receiver is expected to have electricity, but not the sender... I really wonder about the utility if the electricity requirement is still there for one party.

You can do a lot with drones nowadays.
And I can't imagine they'd use anything else since the max range they expect is 1.5km

Re:Until the enemy learns to decode your smoke sig

[fractoid]

I think that's kinda the point - that it's something that would be hard to detect compared to traditional radio, for the same reason that laser speed traps are harder to detect than radar speed traps. This would be a very brief flash, presumably fairly directional, that would only be detectable by someone who was explicitly looking for it.