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Optical Communicator

line-of-sight teletalker
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A fairly simple device, effectively a microphone with the output modulating a torch/flashlight for sending, and a light detector wired to a speaker for receiving. Could come in both one and two-part form-factors.

Handy for talking to your friends, who happen to be some distance away.

There are various details, which are all easily dealt with.
The torch is probably LED-based; LEDs seem to be getting very much better and cheaper recently. These are either 'on' or 'off'. But they can switch very quickly, so we can describe the sound as pulses. The encoding is very basic, published and 'open'.
It may help reduce noise if the detector were to be specific to a certain wavelength. The transmitter can then use that to maximise efficiency. There is probably a 'best' colour for this purpose which is a compromise between LED efficiency, atmospheric transmittance and ease of detection. If made with lasers my guess would be green, but using lasers may have safety and regulatory hurdles to overcome.
Alternatively, one could have several different 'channels' utilising different frequencies.

Loris, Jun 20 2014

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       It should have an option to translate to and from morse code
Voice, Jun 20 2014
  

       if( (detector == camera) && (field_of_view < 10degrees) && (focus == AUTO) && (sensor == COLOUR) && (distance < SPITTING) && (price_of_camera > YOUR_MONTHLY_INCOME) && (flying_pigs_seen == TRUE))
{

it_might_just_work = TRUE ;

}

else

{

it_might_just_work = FALSE ;

}

return(VOID);
8th of 7, Jun 20 2014
  

       If you could somehow construct a type of thin glass wire which could carry the light straight from the source to the detector, you could dispense with the line-of-sight part. You could be on to something here.
mitxela, Jun 20 2014
  

       //If you could somehow construct a type of thin glass wire which could carry the light straight from the source to the detector, you could dispense with the line-of-sight part. You could be on to something here.//   

       Heh, then we'd have a high-tech version of the two cans & a piece of string toy.   

       //if( (detector == camera) && (field_of_view < 10degrees) && (focus = AUTO) && (sensor == COLOUR) && (distance < SPITTING) && (price_of_camera > YOUR_MONTHLY_INCOME) && (flying_pigs_seen == TRUE))//   

       oh, the hazards of pseudocode. You've just set focus to AUTO. And I can get closer to success by losing my job and taking hallucinogens.
Actually, since one can see even a faint light from a distance, I'm not convinced it's impractical. I'm not even sure the receiver would have to be a camera.
Loris, Jun 20 2014
  

       //you could dispense with the line-of-sight part.   

       Hmm, just kicking around an idea, if you were to attach a photo-electric cell to a copper wire, then shine the LED on it, then I believe it might be possible to transmit the message quite a long way, possibly?   

       Of course, the more satisfying version would be to shine the LED light into an internally mirrored-surfaced miniature Klein bottle, which is then strapped to a pigeon, the light (and so the speech) to be extracted at the other end.
not_morrison_rm, Jun 20 2014
  

       Similar to something baked -- look up "lasercom"
sninctown, Jun 20 2014
  

       //You've just set focus to AUTO //   

       Fixed.   

       //since one can see even a faint light from a distance, I'm not convinced it's impractical. I'm not even sure the receiver would have to be a camera //   

       A simple photocell works on average illumination. The change in illumination of a single flashing LED is insufficient to change the signal above the discrimination threshold given all other possible causes of such a change, unless it's a very dark night.   

       An eye (= camera) is a very different device to a simple photodetector.
8th of 7, Jun 20 2014
  

       [8th], did you just use an if statement to test a boolean value then assign that same boolean value to a variable? Do you get paid by the line of code or something?   

       And not only that, but the code doesn't actually do anything, unless it_might_just_work is a global variable. Why not just return the result of the test?
ytk, Jun 20 2014
  

       //A simple photocell works on average illumination. The change in illumination of a single flashing LED is insufficient to change the signal above the discrimination threshold given all other possible causes of such a change, unless it's a very dark night.//   

       Good point. We do need to have a decent solid angle to be able to reliably pickup the feed.
Digital cameras do seem to be pretty cheap now - looking at webcams, for instance. We probably don't need all that many pixels, but we do need a high refresh rate. That probably means it needs to be custom for the purpose.
  

       Although... It would still work at night anyway.
Loris, Jun 20 2014
  

       // [8th], did you just use an if statement to test a boolean value then assign that same boolean value to a variable? //   

       No, we assigned a global static to an integer, but then tested the boolean outcome ... where the assignment should actually have been an equality comparison.   

       // Do you get paid by the line of code or something? //   

       No, by the number of pc's added to the bot-net.   

       // And not only that, //   

       Everyone's a critic ...   

       // but the code doesn't actually do anything, unless it_might_just_work is a global variable. //   

       Yes, it is. Do you want us to cut and paste the .h files and the make file ?   

       // Why not just return the result of the test? //   

       Because it's better to reserve the return() lvalue for an error/status code in case the function is subsequent expanded.
8th of 7, Jun 20 2014
  

       You could build the receiver into a pair of binoculars. Just have the photocell flipped in to one side of the bins. You could look through one eyepiece to locate the light source, and the other eyepiece would act as the detector. That ought to work.   

       Plus you could modulate the LED at a certain high frequency and filter the receiver, making it a lot easier to extract the LED's signal from other (possibly varying) light sources.
MaxwellBuchanan, Jun 20 2014
  

       Or you could go to Aldi or Lidl and buy a pair of PMR446 handsets for twenty quid ... they give you batteries, too.   

       Or you could pick up a couple of discarded St George's crosses for free from the nearest gutter and learn semaphore...   

       Or you could just walk over there and transfer the message using modulated sound waves.   

       But that might be just a bit too practical.
8th of 7, Jun 20 2014
  

       Do the Borg get a lot of party invites, [8th]?
MaxwellBuchanan, Jun 20 2014
  

       Only from you, the Intercalary Twin, and your Uncle-in-law Ko Man Chu.   

       Plus the usual "New Year Party" one from the boy Branson, but we just bin those.
8th of 7, Jun 20 2014
  

       Very wise. If, just once, he wouldn't get drunk and whip out his harmonica...   

       By the way, Great Aunt Halva sends her regards, and said to thank you for the cheroots.
MaxwellBuchanan, Jun 20 2014
  

       Awww, she's such a nice old lady.   

       By the way, is it likely to be "Bring your own goat" again at Samhain this year ? We felt a bit left out, to be honest, although the bonfire was, as usual, beyond reproach, and the idea of putting live piranha in the apple-bobbing tub was truly inspired,   

       Tell Sturton to try rubbing it with a mixture of bicarbonate of soda and female weasel urine, It may not help reduce the swelling, but he is likely to make some interesting new friends, probably mostly male weasels, but then in his situation he can't afford to be choosy.
8th of 7, Jun 20 2014
  

       Knowing Sturton, he has no intention whatsoeveratall of reducing the swelling. In fact, since we share a tailor, I happen to know that he has had a special bathrobe made to accommodate it. If possible, avoid being in front of him in queues.   

       We are doing away with the goat theme entirely this Samhain. Aunt Halva has agreed to open the festivities in the nor' nor' east courtyard, and you know how she is with her allergies. There will, however, still be the swine-lap and hoop-the-seal. Bring the usual gear, and tell your loaders to expect a long night.
MaxwellBuchanan, Jun 20 2014
  

       Possibly something could be done with two small(ish) animals like amoeba and weapon salve? Also needs two microscopes, to see the reactions of the amoeba.   

       Simply lightly stab the amoeba, then switch needles with your contact, then use the smartphone to send a small electric shock to the needle...and so on.   

       Don't forget to label the needles, as it's soooo embarrassing if you swap the wrong ones.
not_morrison_rm, Jun 20 2014
  

       bot nets as well as humans. I bet they have plans for controlling Cthulhu, Hypnotoad, zombiies, and insects as well just in case.
Voice, Jun 21 2014
  
      
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