Exchange Email Addresses With A Handshake

Eye of the Frog writes "Nippon Telegraph and Telephone Corp. and its subsidiary NTT DoCoMo Inc. have developed a device that attaches to your PDA which uses the body's conductivity to transmit data at an amazing 10 megabits per second."

Comments

Re:How about people with pace makers?

[mclearn]

The article states that the device uses the body's natural conductivity. Hence, there should be no issues regarding those with pace-makers.

Re:How about people with pace makers?

[LinuxInDallas]

Pacemakers and other implantables typically communicate with external devices using low power RF signals. It's quite possible that this networking could interfere with operation of the device. There are rumors of airport security x-ray machines causing havoc in some types of devices. It's the responsibility of the medical device manufacturer to make sure an implant meets certain criteria for EMI/RFI but those requirements are not all that strenuous to meet.

Re:Wow

[Henry V .009]

I'd have to disagree with the result. The bandwidth of the penis is given as 78 Mb/s. However, most of our genome is exactly the same for all human beings. So all that really has to be transmitted are the base pairs that differ. This is probably on the order of less than 1%. This means that a cable modem could probably transmit the same bandwidth as a penis using good compression software.

Some Clarifications

[kepart]

I've been doing my PhD work on systems like this (Intrabody Communication). It does work! However, there are a number of issues, some of which aren't clear from the article.

First, 10 Mbps is possible, but that's getting near the theoretical limit. The datarate is limited by the bandwidth, and the bandwidth is limited by the fact that around 50MHz, the signal wavelength is about four times the size of a person, which means the person turns into an antenna, and the whole system becomes essentially a short range radio.

Second, because these systems operate in the near field, the signal travels through a current loop, and not as plane waves in free space. This means that there has to be some kind of grounding path for current to flow back to the transmitter after going through the person. This is why it works so well to put transceivers in shoes -- the ground path can flow through earth ground (or any conductive material in the floor). For devices held in hands, the very small (femtofarad) capacitance of free space is enough, but the signal does suffer more from noise. Devices in purses, etc. also have this problem, and may have difficulty establishing the ground connection depending on the material the purse is made from and the other objects inside it.

One issue that to my knowledge has not been addressed very well is guaranteeing that the signal is received during--and only during--physical contact. There is a large dependence of signal strength on geometry. The devices I've constructed can communicate when they're brought near (~10 cm) of each other, touching or not. There are a few solutions, such as looking at jumps in signal strength, but they tend to be confused when a person without a transceiver happens to touch the object, and a person with a transceiver is nearby. I'm currently working on this problem for my PhD dissertation, so if you have any good ideas or know of related work, I'd love to hear from you.

If you'd like to read more, the first (and most detailed) publication I know about on this idea was Thomas Zimmerman's Masters Thesis at the MIT AI Lab. You find it here: http://www.media.mit.edu/physics/publications/thes es/95.09.zimmerman.pdf

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Kurt Partridge
Dept. of Computer Science and Engineering
University of Washington
Seattle, WA 98195

Re:hehe, nippon

[orthogonal]

whats is the origin of the word 'nip' in racial text to asians [and "wog" and "nigger"]?

"Nip" is short for "Nippon", the Japanese name for their country, or short for "Nipponese", the Japanese name for the people of Japan.

"Nigger" derives from words various European languages use for the adjective "black"; various etymologists speculate in originated in the French, the Spanish, or the Portugese words for "black".

"Wog", a disparaging British slang term for non-European "native" peoples, or in some constructs ("the wogs start at Calais") anyone not British, probably derives from Golliwog, a rag doll with African features in a children's storybook, though some probably apocryphal folk etymologies claim it's an abbreviation -- sarcasticly-applied -- of "Worthy Oriental Gentleman". Apparently the term is also applied, derisively, by mmebers of the Church of Scientology to non-Scientologists (?).

In any case, all these terms are considered disparaging and offensive, especially when used by persons of whom they are not descriptive. (Although "nigger" finds a use, within the black American population when applied to others of the same ethnicity, similar in meaning to "(that black) person".)