One of the pleasures of my field is to find a technical paper written in the driest passive-voice-only larded-with-acronyms style on a subject that is astonishingly, gruesomely science-fictional. Last month’s issue of the Journal of Solid State Circuits had such a paper: “A Pulsed UWB Receiver SoC for Insect Motion Control” by D. Daly et al of MIT, U. Arizona, and U. Washington. In brief, they have designed a chip that is small enough and light enough that it can be wired onto the back of a moth to turn it into a cyborgized spy or weapon. The chip receives radio commands and drives tiny wires that are plugged into the moth’s wing muscles:
The block labeled Rx SoC (that’s Receiver System-on-a-Chip) is the subject of the paper. The “Tungsten Stimulator” is the wires that go into the moth’s muscles, the “DC-DC” block turns the voltage from the battery into a suitable voltage for the chip, the triangle is the radio antenna, the “uCont. & Flash” is a micro-controller chip with flash memory storage of program parameters, and the little rectangle is a crystal that supplies a clock frequency.
The thrust of the paper is how they were able to build a radio of such low power and high bandwidth that it’s able to run off of a battery small enough to be carried by a moth. The whole system only weighs 1.0 grams, but this species of hawkmoth only weighs 2.5 grams, and it was apparently a real challenge just to attach the thing. The receiver can run at up to 16 Mbits/sec, which is a decent rate for a laptop WiFi connection, but only draws a few milliwatts, the kind of power a watch battery can put out.
Yes, you ask, but why? The answer can only be a bone-chilling laugh. Well, that and it’s getting DARPA funding. And it uses an interesting new modulation technique called ultra-wideband (UWB) which is much easier to integrate onto a chip than other kinds of radio. That means that small, low-power radios can be built much more cheaply and therefore used in a much wider range of applications than the expensive multi-component types now found in cellphones.
OK, you say, speaking more slowly and distinctly, but why do they want to put remote controls on insects? Beats me. Here’s all they say about it:
“Scientists and engineers have been fascinated by cybernetic organisms, or cyborgs, that fuse artificial and natural systems. Cyborgs enable harnessing biological systems that have been honed by evolutionary forces over millennia. An emerging cyborg application is hybrid-insect flight control, where electronics and microelectromechanical systems (MEMS) devices are placed on and within insects to alter flight direction. Compared to existing micro- and nano-airvehicles used by the military and other government agencies, insects are appealing because they are small, can travel significant distances, and can carry relatively large payloads. Such a hybrid-insect system would take the best qualities of biology: energy storage, efficient flight control, highly adapted sensing—and combine them with the best qualitiesof electronics: low weight, small size, deterministic control, and interfacing with computation.
Well that’s phrased carefully. One is free to imagine anything: moths doing suicide runs on enemy light bulbs, moths dropping anthrax into terrorist soup, or crowds of moths clogging tank barrels. Once manufacturing scales up, you could have vast clouds of radio-controlled locusts devouring an enemy’s crops. Once you can put a transmitter on the chip as well as a receiver, you could use it as an, ahem, bug.
Sorry. The real reason, of course, is that the only way to get research money out of Republicans is to claim that it has some military application. Cheap, low-power radios would be a great thing to have all by itself, and if the only way to get Uncle Sam to cough up is to pair it with some men-who-stare-at-goats class of project, then so be it.
Update 2/9/2010: The MIT professor who did this study, Anantha Chandrakasan, happens to be at a conference I’m attending. I asked him why DARPA wanted to control insects and his answer was “That’s above my pay grade.” He was interested in the radio design, and a grad student got a nice thesis out of it. The biology part was someone else’s responsibility.