It seems with all this Bluetooth and other stuff the radio spectrum is getting a bit clogged.
No point in re-inventing the wheel so...introducing the NMRM Co Smartphone Semaphore....
Next gen of mobile phones to have little flags to wiggle about, detectable by the camera on the phone you are trying to send the data to. Speed limited only by phone 1's ability to wiggle the flags about without breaking the sound-barrier/your fingers.
Also applicable for near field comms, it wiggles flags with your ID and bank details - comes with cardboard tube to prevent comms interception en route.
For broadcasting 1-to-many - optional fast rotating miniature disco mirror ball pops out of the top of the mobile.
High end version is small teak and brass cabinet say 10cm x 20cm with real flags, low-rent version just shows the flags on the screen (ahh boring).-- not_morrison_rm, Jun 08 2014 Inspired by.. Dead_20Simple_20LED_20Communication [not_morrison_rm, Jun 08 2014] Murray Shutter Telegraph 1795 http://en.wikipedia..._Telegraph_1795.pngDiagram of UK Murray six-shutter system, with shutter 6 in the horizontal position, and shutters 1-5 vertical [mofosyne, Jun 08 2014] (?) Chappe telegraph http://en.wikipedia...happe_telegraph.pngDiagram showing the Chappe system, as used simple for signalling letters and numbers (though it could also be used in an encoded form) [mofosyne, Jun 08 2014] Why not hold a phone in each hand, accelerometers detect your arm movements.-- pocmloc, Jun 08 2014 Better, set fire to your iPhone and then use it to make smoke signals (such as "Help, help, my phone's on fire !")-- 8th of 7, Jun 08 2014 If you are going for semaphores...
Screw the Chappe system, and go for the UK Murray six-shutter system. Much easier to visually process an array of shutters, as oppose to angles of the flags. Not that it cannot be done via OpenCV.
If you are going for the UK Murray six-shutter (6x2)system, you'll need to adapt it for the digital age. Top 1x2 arrays of shutters should be for "clock" and "next char". Bottom 2x2 of shutters would be for Bit0 to Bit3. This will allow for transmission of an 8bit ASCII char in 2 clock cycles.
If you want to go for flag waving route, you could either cheap out and go for servos, or do it hardcore and use those old fashion 'voltmeters' mechanism.
Though for style points, I would rather design a semaphore that looks like 5 little dressed up men waving two flags to the beat of YMCA.-- mofosyne, Jun 08 2014 That's some disturbing imagery you have there, you should probably seek professional help ...
If there are only two flags, why do you need five characters ... ?-- 8th of 7, Jun 09 2014 I wonder how hard you could push a low power laser system for P2P data transfer? Shirley someone has already explored this for use as discreet high bandwidth data transfer?-- Custardguts, Jun 10 2014 //<raises shoe proof umbrella/>
I read that as shower-proof and was confused.. can we have shoes instead of fishbones for topics with relevance to the middle east?-- not_morrison_rm, Jun 10 2014 You just had to throw that into the conversation, didn't you ?-- 8th of 7, Jun 10 2014 "Them drum machines ain't got no sole"...-- normzone, Jun 11 2014 random, halfbakery