Droid 2 Contains Laser Diode??

Discussion in 'Motorola Droid 2' started by AL1EN DR01D, Nov 16, 2010.

  1. AL1EN DR01D

    AL1EN DR01D New Member

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    Hey guys, just some random food for thought, and just wanted to see if anyone can comfirm this;

    One of the Three sensors on the front of the Motorola Droid 2 has intrigued me ever since I first got the phone... the Second Sensor from the top left of the phone always appeared to me as if it could possibly be a CMOS Camera for Video Chatting for when the opportunity would become available via the Verizon network once implemented with the release of the 4G Network, (whenever it would FINALLY be decided to be released... but fat chance)... But I realized recently while in a dark room in the middle of a phone call, I noticed a dim, flickering red light emitting from where that particular sensor is located, and also visually confirmed it by using a camera (NOTE: optical sensors, such as Digital Cameras, Video Cameras, etc. Can pick up Infra-Red Light when emitted from Infra Red sensors such as the one on your TV Remote Controls) Apparently this Low Powered "Laser Diode" sensor is used in the middle of a phone call (when not in speakerphone) to sense whether or not your face is up to the phone to shut off the LCD display to save battery.

    Just Wondering If anyone is able to confirm that this is actually a Laser Diode Sensor; I just find it intriguing that Motorola would put something such as a low-powered laser product in plain view for something as fragile as the naked eye to see.
     
  2. Dave12308

    Dave12308 Silver Member

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    I believe it's an IR emitter, and not a laser diode. Same as you'd find in a remote control but lower power since the range doesn't need to be far at all.
     
  3. nickb1

    nickb1 Member

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    One is a proximity sensor to detect your face during a phone call. The other is a light sensor to determine the backlight level and weather or not the keyboard backlight needs to be on.
     
  4. AL1EN DR01D

    AL1EN DR01D New Member

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    That's what I thought to myself at first too, but isn't Infra-red supposed to be Invisible to the naked eye? Any Laser Diode, especially that found within a CD Player or Laser Mouse can be seen by the naked eye when in the right lighting... not to mention that looking closely at the sensor on the phone (when not active, of course) it appears to look just like a Laser Diode.
     
  5. AL1EN DR01D

    AL1EN DR01D New Member

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    Yes, that's correct, it is a proximity sensor, whereas the sensor to the righthand side of the phone, to the left of the Notification LED is the light sensor to accordingly adjust the brightness on the LCD display & turn on & off the keyboard LEDs. But the two sensors on the left ("Proximity Sensors") is what has me intrigued, since it seems that the first sensor on the left is the reciever & the second sensor (the laser diode) is the transmitter.... My apologies for the "logic" of this discussion, it's just the dynamics of technology intrigues me, especially when it involves something as amazingly small & portable as this particular phone
     
  6. AL1EN DR01D

    AL1EN DR01D New Member

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    Just wondering if anyone has access to something that can measure the power output on this diode just to confirm that this is infact a laser diode?
     
  7. Gibbsinator

    Gibbsinator Member

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    I have two small things to input. Bounce beam, and break beam. Bounce beam sensors can use the same source as to send and recieve the transmission. Break beam uses a seperate tranciever and receptor. Is it possible the light/laser/transmission/whatever is bouncing off of our face and feeding these sensors? Obviously if there are two, they are using break beam, and one would be bounce beam.
     
  8. tonydelite

    tonydelite Member

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    It is most likely a reflective optical proximity sensor. These work by reflecting a beam of infrared light back into itself, off of whatever object is near to it. It is most certainly not a transmissive (or break beam) optic, because that would require an emitter on one side of your head, and a receiver on the other.

    Here's a useful tip: Cell phone cameras can "see" infrared light. If you point your cell phone camera at a television remote and press some buttons on the remote, you will see the infrared LED start flashing through the display on your phone. If you want to see if your phone is emitting any infrared light, borrow someone else's camera phone and look at your own phone through theirs.

    EDIT:
    And it looks like someone did all the work for you: http://supportforums.motorola.com/message/72588
    That talks about the Droid 1, but I doubt the Droid 2 is any different in that respect.

    EDIT #2:
    Here is a link to the OSRAM SFH-7743 Proximity Sensor Application Notes PDF: http://catalog.osram-os.com/catalog...=downloadFile&favOid=020000000002f5fa000200b6

    Here is a link to the full PDF datasheet for the OSRAM SFH-7743 Proximity Sensor: http://catalog.osram-os.com/catalog...=downloadFile&favOid=020000020002c805000200b6

    Hopefully that is more than you will ever want to know on the subject.
     
  9. Gibbsinator

    Gibbsinator Member

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    They are likely using a bounce beam system then. Paintball guns uses these as "eyes" to detect loaded paintballs. I could see this technology being used in this application.
     
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