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Electrochromic-Mirror Mod

Discussion in 'Gen 2 Prius Accessories & Modifications' started by john1701a, Aug 22, 2004.

  1. john1701a

    john1701a Prius Guru

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    That self-adjusting technology is great; however, the actual implementation of it could be a little better. I've had a few owners mention to me that they wish it would darken a touch more when close headlights hit it at night.

    So, today I did something about it.

    Understanding how it actually operates made that fairly easy. There's a light-sensor on front (the mirror side, where the homelink buttons are too) that sees vehicles approaching and responds accordingly. The brighter the lights, the darker it makes the mirror. The catch is, it needs to know how dark it is outside in the first place. Because during the day, everything is extremely bright. Darkening then is not wanted. That's where the second light-sensor comes in. It's on the back. The darker it is outside, the darker it allows the mirror to become based on the degree the other light-sensor tells it. In other words, if you cover the one on back entirely, the mirror will think it is the dead of night (totally dark). Obviously, that's too much.

    So I just fabricated something to the effect of sunglasses for it. I simply taped a piece of transparent dark-blue sheet-plastic over it. See (there's a larger version on page #80 of the photo-album on my website):

    [​IMG]

    That works great!

    From a distance, headlights at night have no effect on the mirror at all... since it is normally off then anyway. But as a vehicle gets closer, the mirror activates and automatically grows darker. And it's not passive like it used to be. That modification seems to force the electrochromic reaction to be more aggressive. So the headlights turn a funky greenish-yellow, rather than the subtle change like in the past. It's pretty sweet!

    I highly recommend all owners with that type of mirror give it a try.
     
    #1 john1701a, Aug 22, 2004
  2. Frank Hudon

    Frank Hudon Senior Member

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    John your way to much! thanx for this as it's going to happen tomorrow on the wife's car. It's one of the things she has complained about all along.
     
    #2 Frank Hudon, Aug 22, 2004
  3. efusco

    efusco Moderator Emeritus
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    Just for completeness sake for futurer searches for this topic I'll add some stuff...beware, the last suggestion is for TRUE GEEKS ONLY!!

    First, similar to the mod John describes (which is very good, I think I'd uses something that blends better myself, maybe run by a window tinting place and ask for a tiny piece of scrap, they've probaby got a ton of it in the trash, which would be almost invisible but do the same job.

    Second, in the early days of the '04 release someone mentioned using black electrical tape and covering about 1/2 of that sensor and getting similar positive results.

    Finally.....and this was NOT my idea, I DID, briefly, try it it, but found it didn't work for my mirror position.

    GEEK ALERT GEEK ALERT GEEK ALERT GEEK ALERT GEEK ALERT

    One problem some people have is that the light from headlights of people behind you are partially blocked by the bar across the rear window and that creates a shadow on the back sensor decreasing the dimming. Some people have found that, by flipping the mirror upside down it places that sensor in a better position for that light to hit it and increases the dimming effect. A second benefit, if you will, is that the shape of the mirror is better suited to the window taper when it's upside down...visibility seems a little better. There is enough slack to flip the mirror upside down.

    Please, unless you're of very strong moral character and your wife isn't on the verge of calling the men in white coats with the padded truck to come get you should you try this...it's just not worth it!!!!
    :oops: :? :wink: :roll:
     
    #3 efusco, Aug 22, 2004
  4. john1701a

    john1701a Prius Guru

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    BLUE was for the sake of making an easy-to-see example.

    The ideal bright lighting helped bring it out too. In normal lighting it is very difficult to see. What's far more obvious is the shiny nature of the tape holding it in place.

    I may end up switching to a more subtle color (like black window-tinting) later, but that really isn't necessary.

    I will likely end up applying a layer of non-reflective type (like 3M satin) over the other tape to reduce the shine.
     
    #4 john1701a, Aug 22, 2004
  5. Frank Hudon

    Frank Hudon Senior Member

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    when you get the desired affect from the blue plastic, cut a round disk and put a very fine bead of black RTV silicone around the outer edge and stick it on. Tha way you can always take it off if you have to.
     
    #5 Frank Hudon, Aug 22, 2004
  6. hdrygas

    hdrygas New Member

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    What kind of blue plastic, and from where? Do I get a bit of blue plastic term paper cover and cut a bit out or what?
     
    #6 hdrygas, Aug 22, 2004
  7. 8AA

    8AA Active Member

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    efusco,

    All my points to you for your great suggestion!

    You were correct that the mirror functions better and fits the shape of the rear window better if it is turned upside down. Not only that, I prefer having the homelink buttons on the top where they seem less intrusive. The only problem was initially, when I had the mirror flipped and pushed up as high as it would go. Unfortunately the overhead console was shading the sensor, so I had to lower the mirror about a quarter inch. Now it works great and looks a lot better. Thanks again!
     
    #7 8AA, Sep 16, 2004
  8. etkal

    etkal New Member

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    <div class='quotetop'>QUOTE(efusco @ Aug 22 2004, 09:04 AM) [snapback]34378[/snapback]</div>
    Evan, thanks, I'll have to try that. The past couple of nights I've become painfully aware that the mirror won't dim with a car right behind me, and it is because the bar between the rear windows casts a shadow right over the sensor.

    I was very close to removing and opening up the mirror to see what the sensor was (i.e. increases or decreases resistance, or is photovoltaic) in order to either (a) add or override one of the buttons to force it to stay on full dimming, or (b) see how to change the recovery delay, so that once it dims because of a headlight it stays that way for a long time.

    One interesting thing about the mirror is that it always comes on when you start the car. After a few weeks of having the car, I would have designed it as follows: Default operations is auto (with a longer return-to-off delay), and with two additional settings controlled by the button, always off or full on.
     
    #8 etkal, May 9, 2006
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