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Please help me identify this device in my car

  1. Apr 27, 2007 #1
    Hello, I hope this is the correct area for my question. Its a bit of a weird one.

    Can anybody help me find out what this device is in my car. I have a 1995 Nissan Skyline GTR, and on the ceiling there is a strange "instrument" that NOBODY has seen before. I have been racking my brains trying to work out just what this thing is. All I can work out is that it is some kind of projector onto the lower central part of the windscreen... but nothing is projected and I can only see it when the windscreen is misted up at night.

    I thought that by taking it apart, looking at how it works, I would be able to deduce its function. How wrong was I?

    The "instrument":
    [​IMG]

    I have asked the question to the owners club and with 60+ replies and 1500+ views we still have no answer.

    I would like to ask you about some possible uses of the unit as it seems to use some sort of optical system to create a possible 3d projection.

    I was able to prize off the panel with slots in and have a look around in there, I can see the lights clearer and what looks like more mirrors and prisms.
    [IMG=http://img223.imageshack.us/img223/995/p4250722in8.jpg][/IMG]
    [​IMG]

    I removed the unit from the roof (it was bolted in as if it came out like this from the factory) and disassembled it. This lead to even more questions.

    The box contained a series of mirrors and a silver slide....There is a halogen spotlight that shines into the slide.
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]

    There are only three connectors on the board - one power, one to the controls and the other to the light.
    [​IMG]

    The circuit board that can be seen uses a hex schmitt inverter for power and that is all the circuit appears to do.

    There is a full collection of 35 pictures on my website: http://lonewolf-online.net/blog/2007/04/25/strange-lights-in-gtr/

    And the original discussion on the owners club where we bounced around a few ideas.

    http://www.gtr.co.uk/forum/upload/74481-help-wtf-light-calling-all-sherlock-holmes-wannabees.html


    Can anybody here see what this device could possibly be used for?

    Please, please please HELP!!!


    Kind Regards

    Tim
     
  2. jcsd
  3. Apr 27, 2007 #2

    Danger

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    Bloody hell... :confused:
    Fascinating pics and discussion. Have you tried contacting Nissan directly? Surely their design engineering department knows what they built.
    My first thought was HUD, but that seems to be ruled out.
    Can you trace the light path through all of the mirrors and prisms to see what they do (and hence why they're there)?
    Welcome to PF.
     
    Last edited: Apr 27, 2007
  4. Apr 27, 2007 #3

    turbo

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    Heads-up display for projecting tach/speedo readings on the windshield?
     
  5. Apr 27, 2007 #4

    berkeman

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    The hex Schmidt inverter IC could be used to digitize the potentiometer voltage into a 6-bit priority encoded signal. What does turning the potentiometer knob do to the lights? Does anything change when the car is moving? (have somebody else watch, please)
     
  6. Apr 27, 2007 #5

    turbo

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    Hey, maybe it's for the drag track. It senses the color of the Christmas tree and dumps the clutch for you. ;-)
     
  7. Apr 27, 2007 #6

    NoTime

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    Looks like some money was spent on that!
    The first mirror after the slide looks like a combo beam splitter color filter from what I see of the photos.

    You said that the light source for the slide is a halogen bulb.
    Light output shown in photos seems real low for that.
    Is the bulb have a normal halogen brightness when powered up?
    Could the power control board for the lamp be defective?

    If you move a target screen closer or farther from the front of the unit, do the two optical paths converge at some point?
    Ie:Show a single image of the cylinder on the screen.
    (assuming you haven't moved any possible mirror adjustments)

    The only two things I can think of is a distance measuring device or a spy quality door opener.
    Neither of which make much sense.
     
  8. Apr 28, 2007 #7
    Hey, thanks for all the replies.

    The potentiometer adjusts the brightness of the light. It may not be a halogen light, but that was my first guess. Se what you think:
    [​IMG]

    I tried using some paper as a target screen and the light paths are to diffuse to project anything, even inside the unit as they exit the 'box'. Its as if there is a lens missing. By the time the light reaches the windscreen I can only just see the area illuminated on paper. There are diffused horizontal lines on the paper, but I suspect that these are diffraction lines from the slats.

    Thanks so far.

    Tim
     
  9. Apr 28, 2007 #8

    FredGarvin

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    This may be a stretch, but considering the racing and other circles that really appreciate this car, could it be some kind of simple lighting kit? I'm thinking along the lines of the under body neon kits and the like. Could it just be for display purposes at shows to give some kind of lighting effect? I can not see any "useful" purpose for the lights.

    Maybe someone was going to put in a front projection screen tv in???

    Where did you purchase the car?
     
    Last edited: Apr 28, 2007
  10. Apr 28, 2007 #9

    Danger

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    I just noticed something. The first time around, I didn't pay much attention to the close-up of the circuit board because I don't know anything about electronics. At second look, I see that there are 3 wires labelled R, B, & G. That would indicate to me that this thing is supposed to be a tri-colour device. If so, there should be a blue lens in there somewhere and it would be practical as a full-colour image projector.
    That does look like a typical halogen reflector bulb from the front, but it certainly doesn't seem bright enough to be one. Maybe it's on its last legs. Can you replace it with a new one and see if it makes a difference?
     
  11. Apr 28, 2007 #10

    NoTime

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    Given your comments, the light intensity involved and construction.
    It's not capable of doing anything meaningful on its own and not going to be noticeable to the casual observer.

    The only thing that makes some sense is to have an external camera array view the slide.
    I suppose that gives some credibility to the spy quality door opener idea.
    But, I would think anyone going thru that much trouble would want to validate the occupants of the car.
    No clue.
     
  12. Apr 28, 2007 #11

    NoTime

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    The wire used would not be good for video.
    Probably just as good a guess as any other I've seen though :smile:
     
  13. Apr 28, 2007 #12
    I think the R,G,B refers to the wire colour, these wires go to the switch/potentiometer, and like NoTime said, these cables would not support an av signal very well as they are not shielded.

    We have had a development over on GTROC:

    --http://www.gtr.co.uk/forum/upload/74481-help-wtf-light-calling-all-sherlock-holmes-wannabees-5.html#post668664

    Sounds good to me how about you? I'll be testing this out later tonight.


    Cheers
    Tim
     
  14. Apr 28, 2007 #13

    Danger

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    That's an interesting and logical theory. The only part that bothers me about it is that such a system would have absolutely no need for all of the internal optics. The same thing can be done with a couple of coloured bulbs and a polarizing filter.
    You're right about the wires not being AV quality. Sorry that I wasn't clearer; I didn't mean that a video signal went through them—rather that they might carry control signals for colour generation elsewhere.
     
  15. Apr 28, 2007 #14

    Danger

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    I'm back. I've taken a lot of long-shots in my time, but this is a stretch even for me. Is there any chance that you might have stumbled upon the remains of an early prototype for one of these things: http://gauss.ffii.org/PatentView/EP756246?


    Other than that, the only other thing that I can think of is that maybe your car was used in a movie and tricked up with useless FX stuff like Viper or the Knight Rider Trans Am.
    edit: Actually, that would explain the dimness; it could project an image directly into a camera without overwhelming the rest of the frame.
     
    Last edited: Apr 28, 2007
  16. Apr 28, 2007 #15

    NoTime

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    I have to go with Danger on this.
    The device is way too complex for this function.
    I've used low light map reading devices, they are simple, cheap and effective.

    Probably, too complex to be a leftover FX prop as well.
    I would think a little CGI would be much simpler and cheaper.
    But, I kinda like the idea :smile:
     
  17. Apr 28, 2007 #16

    Danger

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    The only thing that made me think of a movie prop is that a similar model of car was featured in "Too Fast, Too Furious". I never saw the show, but it just tripped a synapse. As to the cost effectiveness of such a device over CGI, it would depend upon how often it's used during a show. Given the vintage, more than half a dozen or so CGI effects could have cost more than building a real unit.
     
  18. Apr 29, 2007 #17

    Astronuc

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    Along the lines of Fred's questions, I was wondering if one is the original owner. I would imagine that if one bought the car at a dealership, one would know about the device. In that case, ask the original owner, unless it was purchased at a 'used'-car dealer, and of course, they tend not to know much about anything. :rolleyes:

    From some of the images, it looks to have a 3D quality, so I was thinking along the lines of a holographic projector. But the image of hand under the rearview mirror indicates that it may be a night vision light. Do people race these in 24-hr rallies?

    The multi-mirrors remind me of setups for laser beam splitting.
     
  19. Apr 29, 2007 #18

    Danger

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    That's one of the things that's bugging me so much. The whole set-up appears to be of supreme optical quality suited to laser applications, so what's that bloody light bulb doing in there? :frown:
     
  20. Apr 29, 2007 #19

    turbo

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    Nissan produced some cars with electronically controlled suspensions, and the first car with an active differential was the '95 Skyline. The optical quality of the unit makes me think that somehow the two beams (red and green) are being compared somehow, and the result of that comparison provides input to a controller that regulates an active system like one of those.

    Edit: and the first car with 4-wheel steering was the 1985 Skyline HICAS - another possible system to control.
     
    Last edited: Apr 29, 2007
  21. Apr 29, 2007 #20

    Danger

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    And yet again, we come to that damned light bulb. That's a serious indication that this is an output device, not some sort of sensor. The only reason that I can think of for having a light source within an input unit would be to generate some sort of interference pattern relative to the scanned scene.
     
    Last edited: Apr 29, 2007
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