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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."
DARPA researchers discover messages can be transmitted using nothing more than a simple mirror.
cause, you know...sending smoke signals when stranded in enemy territory is really going to help you....
"Our goal each year should be to increase the number of goals we set for ourselves!"
Step 1, smoke a cigarette under a poncho. Step 2, light an "infofuse". Step 3, get shot in the face.
My Drill Sargent demonstrated how easy it is to spot someone smoking in the dark.
Is a crank-powered radio really out of the question? I mean, it would even work during the day.
-Peter
So it only transmits 2 km, and presumably someone has to be looking in the right direction to receive your signal, and you need some kind of special equipment to encode a long message. This just looks like the wrong approach. It seems to me there's always a trade-off between distance, information transmitted, and signal power (a rough restating of Shannon/Hartley). I don't know how far flares can be seen, but that's already a chemical means of sending a short message a limited distance.
One thing that might be interesting, the ability to produce a powerful radio signal by some chemical means. You wouldn't be able to transmit much information beyond say "help!", but if you had a satellite in geo-stationary orbit looking for these signals (and somehow triangulating the position) that might solve the "has to be someone looking" problem. Whether there are chemical reactions that produce radio signals, I have no idea.
AccountKiller
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.
Well, after I RTFA (sacrilege, I know), the point would seem to be data density. The signals are read by a CCD, not by a human interpreter, though I'm sure there is decent software out their for parsing morse code. It takes a while to send morse code signals if you're not in good practice, and the whole time you're sending the signal you're vulnerable. So the signal "fuse" has the advantage of transmitting an encoded message faster than most people using morse code could.
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.
"Trolls they were, but filled with the evil will of their master: a fell race..." -- J.R.R. Tolkien on Olog-hai
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".
You only need to have one preset message:
"Enemy advancing on current position."
"There is more worth loving than we have strength to love." - Brian Jay Stanley
I guess if they have a airman down in hostile territory with the enemy having access to frequency monitoring equipment, how does the person transmit his coordinates without broadcasting anything.
Reminds me of those experiments that we used to to do in cub scouts - sticking a small mirror onto a thin sheet of clingfilm and watching how sound waves changed the direction of reflected light - to demonstrate how sound was just air moving rapidly.
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