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Model S Sneak Peek: Alpha Drives

Discussion in 'Model S' started by TEG, Aug 2, 2011.

  1. TEG

    TEG TMC Moderator

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  2. AnOutsider

    AnOutsider S532 # XS27

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    pretty cool! FYI, anyone wanting to watch fullscreen, go direct to vimeo, I think the boards disable fullscreen


    *edit* I think the small arms make the side mirrors look bulky
     
  3. Adm

    Adm Active Member

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    New video of the Alpha prototype on the Tesla website.

    [video=vimeo;27072425]http://vimeo.com/27072425[/video]
     
  4. Lloyd

    Lloyd Active Member

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    It's too Short!!!! I WANT MORE!
     
  5. Adm

    Adm Active Member

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    Having watched the video 20 times to compensate for the fact it's only 25s there appears to be little new to be seen on the video. Or to hear for that matter and I like that. Just some roll noises of the tires.
    I may have to take a vacation to stake out the Tesla facility to see it first hand. Don't leave one of the Alpha's with the keys in it guys!!!
     
  6. Mycroft

    Mycroft Life happens

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    Considering several Betas have been completed, you might as well go after one of them. :)
     
  7. JimmWilks

    JimmWilks Member

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    Ohhh too short. My initial reactions are cool, and I don't like it in black.
     
  8. Tommy

    Tommy Member

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    At the end of the video, as the third car drives by the two other Alpha's, all three car's right rear lights begin to rapidly blink in unison. Anyone want to venture a guess whats going on. Is it Tesla's way of saying "hi" to a a fellow Tesla driver.
     
  9. doug

    doug Administrator / Head Moderator

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    It's a beating between the strobing of the LED taillights and the frame rate of the video camera.
     
  10. jaanton

    jaanton Roadster NA #1026

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    Nice. I think that's the track behind the Tesla Factory. Good to see them using it.
     
  11. vfx

    vfx Well-Known Member

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    Possibly, but it should be consistent in all cars in all shots all the time. Perhaps at that moment new light comes on like a brake light that is out of phase with the camera shutter.

    Another wild theory. Maybe they transmit signals from base or the lead car and the flashing light is the "accepted" signal.
     
  12. doug

    doug Administrator / Head Moderator

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    No, it's just that when the brakes are on, the duty cycle on the LED taillights goes to 100% (and are thus no longer strobing) so that the naked eye perceives them as brighter.
     
  13. TEG

    TEG TMC Moderator

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    #13 TEG, Aug 2, 2011
    Last edited by a moderator: Mar 13, 2016

     
  14. vfx

    vfx Well-Known Member

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    #14 vfx, Aug 2, 2011
    Last edited: Aug 2, 2011
    LED headlights should do the same thing. (assuming their flash rate is out of shutter phase) What type are the S lights? Looks like the one(s) coming at us is slow flashing. The slower one it's right bulb.
    You can the orange turn signal flashing when it's parked (earlier in the cut).
     
  15. dpeilow

    dpeilow Moderator

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    Maybe they are using optical WLAN to allow for those road-trains we keep hearing about :)
     
  16. vfx

    vfx Well-Known Member

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    Why would they need to trailer the cars in (as implied)

    By the way. That truck and trailer is as quiet as the EVs....
     
  17. vfx

    vfx Well-Known Member

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    Did anyone notice the storytelling here? They seem to be going out of their way to say they have three running cars but interestingly only two are moving at a time the way it was edited.

    I'm not saying anything conspiratorial, it's just interesting. Like maybe they realized afterwards they never had the right footage and did the split screens to explicitly say that two are working at once and giving the feel of three working simultaneously to match the predetermined or favored title.
     
  18. doug

    doug Administrator / Head Moderator

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    groan... this quote has some truth mixed with nonsense.


    LEDs don't necessarily flicker. They are sometimes pulsed with a variable duty cycle to affect their perceived brightness since the eye acts as an integrator. In the taillight example, when the lights are off the duty cycle would be 0%, when the headlights (or parking lights) are on the taillight duty cycle might be 50% (perceived as half brightness) , and when the brake pedal is depressed the duty cycle would be 100%.

    That pulse rate doesn't have to be very high. Movies are at 24 fps, standard TV 30 fps. I'd guess standard LED taillights are using somewhere around 60 Hz since you can actually see them flicker with the naked eye if you look quickly from one side to the other. Certainly less than 100 Hz and not what I'd call "a very high frequency" (e.g. VHF is defined as above 30 MHz).

    The orange light at 0:23 in the video is flashing because the turn signal is on.

    Since the frequency of the LEDs' strobing and the frame rate of the camera are different, phase isn't so much the issue. You can look at is as the relative phase constantly changing, which gives rise to the flickering you see on the video. It's beating. I linked to this before: Beat (acoustics) - Wikipedia, the free encyclopedia. Even though that's in the context of sound, it's the same phenomenon and the same math. In fact if we assume the camera is at 30 fps, we can calculate the LED strobe rate by measuring the beat frequency.

    Hopefully that's a thorough and clear enough explanation.
     
  19. AnOutsider

    AnOutsider S532 # XS27

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    I'm going to guess you're reaching REALLY hard here...
     
  20. TEG

    TEG TMC Moderator

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    By the way, I was just quoting a Youtube comment... Not my own words...
     

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