Automatic Sunglasses, No Battery!

There are some projects that are so simple they require very little description, and [Bobricius’s] automatic sunglasses definitely fit into that category. Their story starts with the fad for 3D displays a few years ago, a resurfacing of the movie business’s periodic flirtation with the third dimension in the hope of using the gimmick to bring in more moviegoers. There was a time when you could hardly encounter a new TV or graphics card without it coming with a pair of cheap plastic glasses with LCD panels instead of lenses that would alternately shutter the view for each eye to create the 3D illusion.

Of course, once everyone had seen the film with the blue aliens and tried a few other titles on their new toy, they grew tired of headaches, nausea, and half-brightness. The glasses gathered dust, and the fancy 3D telly never ventured beyond two dimensions again. Except for [Bobricius’s] glasses, that is, for he’s levered out the 3D driver electronics and replaced them with a tiny SOIC-8 solar cell. Light hits the cell, the LCD gets a charge and darkens, no light and they remain transparent. Similar to welding goggles — though they usually use a battery. It’s unclear whether they can get a little too dark on a really bright day and whether they are something akin to [Zaphod Beeblebrox]’s peril-sensitive sunglasses, but we really applaud the idea. They are so simple that this Hackaday write-up is probably longer than their write-up, but they remain a neatly executed idea and we like that.

You can, of course, use a battery, or achieve the same effect by more complex means. But if the [Beeblebrox] glasses are closer to your requirements, we’ve got that covered too.

26 thoughts on “Automatic Sunglasses, No Battery!

    1. Yeah, I was about to say. What’s up with this automatic sunglasses thing? I though it was just a shittyrobots meme. My grandma has had self-darkening lenses since the ’90s.

      1. Those don’t work for prior who drive cars because they depend on UV exposure which is blocked by most wind screens. Also, they often have issues with self lightening quickly enough, finally, they wear out with time.

    1. Just get two polarizing filters on top of each other and rotate them to block and not block, that way it’s all mechanical.
      Hell you can even get the standard filters for cameras and attach a lever to rotate them, they sell so-called adjustable neutral density filters that work that way and those can’t be hard to adapt.

  1. Most important thing is how those LCDs block UV radiation. Eyes will react to lower visible light levels by expanding iris, and if you didn’t block UV light you’re exposing your retinas to dangerous UV radiation without knowing it.

    1. Nope. Total BS. No UV ever hits the retina in most humans. The lens cuts off everything bluer than about 400 nm. If you happen to be without a lens (say, due to cataract surgery) you can see out to 320 nm or so (where the cornea starts cutting off). There’s anecdotal evidence this was used during rum-running days, where persons able to see UV acted as navigators, to find the rum-running boats running dark, but flashing a UV beacon not visible to enforcement people. A real hack. (thanks Volstead, for the economic boost!)

      1. Lens protect retinas by absorbing UVA, which destroys it with time. Also UVB and UVC are considered to be harmful for human eye. So even if retinas don’t get damaged by UV, other parts of the eye will. So you still have consideration how well LCD screen in those glases protect your eyes from those three types of UV radiation. I’m not saying it doesn’t, just have to be carefull with such DIY devices if they’re not properly tested.

        1. Even the cheapest sunglasses filter out near 100% of the UV, the reason is simple, plastic does not transmit UV very well. There are some thing that do transmit UV but they are rare. Even regular glass is not real good at it. That is why many photochromic glasses do not work so well in the car. I suspect with the multiple layers of plastic and the plastic polarizer in the glasses that not much UV gets through them and they are on par or better than normal sun glasses.

          1. About the photochromatic lenses in the car….they don’t work very well becuase the laminated windshields have UV filtering materials in them to protect the vehicles interior; as we all know plastic doesn’t like UV.

            You’re right about glass not being great at UV transmission…but fused quartz glass does transmit it pretty well.

          2. That couldn’t be more wrong. There’s a lot of transparent materials including many glasses and plastics that pass UV just fine in sufficiently dangerous amounts.

            Normal sunglasses don’t because they are designed that way, they specifically use polycarbonate for this reason, not just that magic catchall word “plastic”. UV isn’t also the only problem. Heating from IR can be just as bad, but unlike UV many sunglasses don’t block IR either.

        2. You are correct. This is one area where incorrect information can cost you. If UV wasn’t a danger we wouldn’t need welding goggles. Polycarbonate degrades from exposure to UV so they add UV blocking chemicals to it in order to extend its life. That is why Eyeglass lenses made of polycarbonate block UV. Your optometrist can visually see UV burns on the cornea. You only get 2 eyes, dont risk them with something like this.

          Ultraviolet C radiation is responsible for photokeratitis of the cornea and erythema of the skin (sunburn).
          Ultraviolet B radiation is responsible for photokeratitis of the cornea, skin cancer, and accelerated aging.
          Ultraviolet A radiation is responsible for photochemical cataracts, pigment darkening and skin burn.
          Visible radiation is responsible for photochemical and thermal retinal injury, photosensitive skin reactions and skin burn.
          Infrared A radiation is responsible for cataracts and retinal burns and skin burns.
          Infrared B radiation is responsible for corneal burns, cataracts, damage to the aqueous humor, and skin burns.
          Infrared C radiation is responsible for corneal and skin burns.

          https://www.phys.ksu.edu/personal/macf/safety-training/jrml-web-training.htm

        3. That’s super interesting. I didn’t know there were people who could see higher parts of the spectrum. I know there’s tetrachromats out there who supposedly process four primary colors instead of three.

          I’m colorblind, but of course that only means I can’t differentiate as well between parts of the spectrum. I still successfully detect those wavelengths on my retina. Curiously I’ve heard that colorblind people have better rods to make up for worse cones, so we have better contrast and low-light vision. I wonder if that means we get a slightly expanded wavelength bracket.

          How do you test to see if you’re one of those people who can peek uv wavelengths? I’d love to give it a try.

  2. “There was a time when you could hardly encounter a new TV or graphics card without it coming with a pair of cheap plastic glasses with LCD panels instead of lenses that would alternately shutter the view for each eye to create the 3D illusion.”

    Reading a book were it was used as part of AR efforts.

    1. hmmm…
      I do remember 3D TV’s but I had no problems at all in buying a regular TV at that moment.

      What I do had (and still have) problems with is “smart” TV’s… I wanted a regular TV (or actually I required a monitor, because of the settop box craze over here in europe). I recall that the cheapest TV I liked wasn’t available without the “smart” function… I could find the same model without “smart” but it was €50,- more expensive.
      So I went with the “smart” one… then the problems started… I requires an update every week at the most inconvenient moment (when I want to watch TV). It responds to my commands (via the remote) in a very unpredictable manor. Sometimes the menu pops up… sometimes it doesn’t at all and I need to restart the TV.
      Perhaps I should have bought a 3D TV, then I at least have had some nice glasses.

      Regarding the project… I’ve seen projects about LED’s connected to batteries that had more content. The project page is mostly empty… more details please. Where were the gutted electronics from the glasses and why weren’t they reused. Using DC for a LCD isn’t a good idea. The old electronics could have solved part of that problem,
      Where did he buy these and what did he pay for them? How well does this actually work as sunglasses? What is the polarization direction of the glasses (when not shuttered), need to know this in order to play my gameboy (B/W) without problems? To me this project seems a little shady (pun intended).

        1. Man, screw that. I have a great old plasma that my buddy threw out with a bad power supply. Just had to replace some caps, a fuse and an oscillator and it was good as new. Hook up a little linux computer, add a bluetooth keyboard, and write some scripts to control the TV over HDMI’s CEC protocol (IR can go to hell) and that’s a much better DIY “smart” TV.

      1. The first thing any sane person does with a ‘smart’ TV is block it from getting internet access.
        Something that is relatively easy you would think since you can just not plug in a LAN cable and not give it a WiFi password.
        If it somehow still manages to go through free WiFi or something unlikely then a resistor over its antenna will fix that.

        And if you absolutely must have youtube or netflix or something on TV then you can get a separate box for it, that you can turn off and control.

  3. This makes me wonder what you might do with the cracked screens from TVs??
    A google search just seems get busted cell phone discussions and few comments saying that TVs aren’t cost effective to repair.
    Yeah yeah, I know the TV’s not a candidate to repair, I just want a use for the leftover bits.
    …Gotta be something cool to do with the carcass.

    1. Tossing any circuit boards and lights into the parts box was definitely in mind.
      I vaugly recalled seeing a couple of projects built from monitors or TVs
      https://hackaday.com/2008/09/22/broken-lcd-tv-turned-into-a-light-table/

      https://hackaday.com/2018/05/09/broken-screen-becomes-polarizing-art-lamp/

      But I keep looking at the screen itself and wondering what other cool items might be derived from them?
      Just that nagging feeling that I’m forgetting about something simple.
      Cheap widgets for photography seems to be in my fuzzy brain.
      Is the fluid worth trying save? etc…
      But I’m just not getting a clear idea.
      I’d hate to trash the broken/cracked panels and THEN see the nifty hack for them.

      Ha Ha, Maybe I’ve just been reading things around here for too long??? :p

  4. No batteries you say? That’s incorrect, as the article states it uses a photo “cell” whose full term is photovoltaic cell. It’s just not using a primary or secondary “chemical” cell. Battery is used when combining more than one cell to typically increase the collection’s output voltage. Pedantic, but true.

    BTW: there are photo transistors optimized for UV detection (e.g. GUVA-S12SD used in http://www.adafruit.com/product/1918 or the full spectrum Si1145 used in http://www.adafruit.com/product/1777).

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