This is a device for people, active in the singles bar/dating industry, worn on your person, that is used to transmit and receive then analyze personality traits for pre pickup line vetting purposes. So, for example if two adjacent people noticed that the other's fly mounted Green LED was blinking, it
would indicate that verbal communication might be productively established. If blinking Yellow, or God Forbid, Red, it is perhaps a bad investment. Favorite music, movies or books. Professional, policical or religious affiliations.
The system would allow you to filter out personalities that are unlikely to be compatible so as to avoid the wasted time and psychic toll of failed approaches and further to identify traits in a promising target that are likely to establish topics of enthusiastic participation.
Ideally it is really an open communications protocol and an open personality database structure protocol that can be used in unlimited ways by a variety of hardware and applications vendors.
The low level physical transport could be active or passive RF like BlueTooth, RFID or some Wifi/TCP port, or IR. The transducers, depending on type, can be tightly directional, for positive location, or omni-directional, for wide area trolling.
The low level data structures could be simple serial, or TCP/IP or whatever. However, in the case of advanced conditional info transfer some encryption may be required.
The devices could be standard PDAs, programmable cell phones, programmable MP3 players or custom stand alone technology so long as they're equipped with the neccesary comm. transceivers, either standard, lapel or fly mounted in the case of directional systems. PDAs would allow review of specifics or ad-hoc data manipulation for special cases where she's so hot you don't care that she's a republican.
Advanced systems would have an info transfer flowchart so that you can reveal information to other systems subject to the other system meeting certain criteria. This of course creates a deadlock possibility such as as 2 gay men in Dallas might encounter.
The Database would need to be flexible and open because it's impossible to know what criteria people might require of their mates. Smokers are out, but they must like Indian Food and Film Noir. The systems would need to accept new criteria and those new criteria need to be acquired by new aquaintences and later those criteria can be voted on or specifically ignored by the recipient.
So you see it is an open ended system and requires open structures that can be modified. It could be quite complicated. Bake-On!