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10/18/07 14:12
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 		 #145888 - They need to heavily amplify the signal
Responding to: ???'s previous message
Jon said:
Does anybody have an idea how sensors like these project a visible red beam without using a laser? I've been all over the place looking for information on photoelectric sensors and not found an answer. I'm assuming they have to use a narrow view angle LED and a culminating lense or something.

Yes, they use such a small emitting angle LED, but also a modulated beam, as mentioned in the datasheet.

The reflector element could be made of the same technique as the mirror the NASA put on the moon to measure the distance between earth and moon. This mirror reflects the beam always into exactly the same direction as being recieved. I'm not sure about this, but I think they use a prism or something like that. But the NASA hint should give you an idea of where to search for more details.

Nevertheless, only a small portion of beam will come back to the photo diode and they have to amplify the signal a lot.

Kai


List of 106 messages in thread
TopicAuthorDate
Optical Sensing Recommendations            01/01/70 00:00      
   Video Babyphone            01/01/70 00:00      
      Babyphone and white light            01/01/70 00:00      
         Fluorescent ink?            01/01/70 00:00      
            Or.            01/01/70 00:00      
            RE: Flourescent ink and UV light            01/01/70 00:00      
   Dragging and dropping the links from your post...            01/01/70 00:00      
      Links            01/01/70 00:00      
         you need to add the closing tag for image            01/01/70 00:00      
   It depends on what sensor you are using            01/01/70 00:00      
   Reflected laser light            01/01/70 00:00      
      Laser Pointer            01/01/70 00:00      
         An ultra-bright LED can be comparably intensive            01/01/70 00:00      
            Only with a lens on it            01/01/70 00:00      
               Not necessarily            01/01/70 00:00      
                  I don't think...            01/01/70 00:00      
                     Marking the end of ribbon or certain length?            01/01/70 00:00      
                        aaaaaaah.... me stupid...            01/01/70 00:00      
                        End Goal            01/01/70 00:00      
         Way to go.            01/01/70 00:00      
            I prefer this one            01/01/70 00:00      
               ...is the laser...            01/01/70 00:00      
                  The laser is mounted in my helmet            01/01/70 00:00      
                     Is it that "all in one" type of helmet...            01/01/70 00:00      
                        Yes, but unfortunately it's a classified project..            01/01/70 00:00      
               Why bother with anything but a laser ...            01/01/70 00:00      
                  laser safety            01/01/70 00:00      
                     Not brilliant you say!?            01/01/70 00:00      
                        Laser classes            01/01/70 00:00      
                           it seems we had more cautious teachers...            01/01/70 00:00      
                              Spectacular            01/01/70 00:00      
                        safety can not rely on human reactions...            01/01/70 00:00      
                     OOPS!            01/01/70 00:00      
               Highly effective            01/01/70 00:00      
                  LOL!            01/01/70 00:00      
                  For defending our family...            01/01/70 00:00      
                     kissing cousins            01/01/70 00:00      
                     Slow criminals            01/01/70 00:00      
                        Yeah, we train them to wait...            01/01/70 00:00      
                           Hard to argue            01/01/70 00:00      
                              to shoot or not to shoot            01/01/70 00:00      
                              Beslan            01/01/70 00:00      
                                 Beslan            01/01/70 00:00      
                                 Relativity            01/01/70 00:00      
                                    Not my point            01/01/70 00:00      
                                       How many would have died otherwise?            01/01/70 00:00      
                                    Naïvety            01/01/70 00:00      
                                       My only question then ...            01/01/70 00:00      
                                          Joseph, please!            01/01/70 00:00      
                                             What are the numbers? ... the problems?            01/01/70 00:00      
                                                Numbers            01/01/70 00:00      
                                                   responses to Joe, to Rob            01/01/70 00:00      
                                                      re:Video games            01/01/70 00:00      
                                                         we were playing shooting all my childhood...            01/01/70 00:00      
                                                            Hey, me too. :)            01/01/70 00:00      
                                                            the diffrence            01/01/70 00:00      
                                                               In our case, ...            01/01/70 00:00      
                                                                  Fond memories            01/01/70 00:00      
                                                         Me too.            01/01/70 00:00      
                                                         What about the laser light?            01/01/70 00:00      
                                                            Laser Light            01/01/70 00:00      
                                                               Tracking or what ?            01/01/70 00:00      
                                                                  Detecting            01/01/70 00:00      
                                                                     Easier then            01/01/70 00:00      
                                                                        irfa red and short exposure times            01/01/70 00:00      
                                                                           External (noise) light sources            01/01/70 00:00      
                                                                              We use optical filters            01/01/70 00:00      
                                                                           to suppress external light...            01/01/70 00:00      
                                                Statistics            01/01/70 00:00      
                                                   Lies and statistics            01/01/70 00:00      
                                                      more            01/01/70 00:00      
                                                Problems            01/01/70 00:00      
                                                   Oldest case            01/01/70 00:00      
                                    Perhaps this is all wrong-headed!            01/01/70 00:00      
                        Not slow, just different.            01/01/70 00:00      
                           different indeed            01/01/70 00:00      
                     ... It ain't necessarily so ...            01/01/70 00:00      
                        Why have you elected this man, then?            01/01/70 00:00      
                           He's good for a laugh or two!            01/01/70 00:00      
   Update            01/01/70 00:00      
   Works like a charm!            01/01/70 00:00      
      Congrats!            01/01/70 00:00      
      Caution...            01/01/70 00:00      
         2 1/2 years            01/01/70 00:00      
            That's why I suggested an utra-high eff. LED            01/01/70 00:00      
               Hurry            01/01/70 00:00      
                  industrial sensors            01/01/70 00:00      
   Photoelectric Sensors            01/01/70 00:00      
      industrial solution, finally... :-)            01/01/70 00:00      
         Industrial solution            01/01/70 00:00      
      For reasonable quantities, or one offs            01/01/70 00:00      
         Cool Place            01/01/70 00:00      
            I can't download the latest catalog...            01/01/70 00:00      
               I couldn't either            01/01/70 00:00      
                  Email Fred Olsen            01/01/70 00:00      
      They need to heavily amplify the signal            01/01/70 00:00      
         See            01/01/70 00:00      
            Ah, yes, thanks!            01/01/70 00:00      
               just a thought            01/01/70 00:00      
   I just happen to recall            01/01/70 00:00      
   Update 2            01/01/70 00:00      
      Take care of your eyes, please!            01/01/70 00:00      
         Pff, mere candles ;-)            01/01/70 00:00      
            Does the lantern contain 4000 LEDs?            01/01/70 00:00      
               85            01/01/70 00:00      
                  Oh yes, that's bright indeed!            01/01/70 00:00      

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