I am looking to create a projector effect similar to one seen in projector alarm clocks like


and I am looking for some module that would accomplish it


This is the closest thing I can find to what I am looking for but it's very pricey I would think given how popular these sorts of alarm clocks are there would be something much cheaper and easy to get your hands on out there.

  • This isn't an Arduino question. It would be a better fit in one of the electronics forums.
    – Duncan C
    Nov 13 '20 at 14:08
  • Retail consumer products have economies of scale working for them. A designer can spend the money to configure a factory to build a consumer product, and then spread that setup cost over millions of units. My guess is that the projected alarm clock you show is a bright LCD or LED display and a simple lens to project it's image. A general-purpose DLP projector like the one you linked is a much more sophisticated product.
    – Duncan C
    Nov 13 '20 at 14:10
  • 2
    These alarm clocks often only have a bright 7 segment LED display, which is then projected by a simple lens. Or maybe a simple custom LCD display, which is then backlight by a bright LED. The linked product from mouser is a complete DLP display with 640x320 pixels. Thats just different technology in a different league
    – chrisl
    Nov 13 '20 at 14:11
  • Buy the alarm clock and scavenge the parts you need from it.
    – Gerben
    Nov 13 '20 at 14:15
  • Except that I bet those alarm clocks have custom LCD displays that can only display the time, plus a few custom graphics, and nothing else. I very much doubt if they are general-purpose raster displays. If you find an alarm clock that has the display you want, great.
    – Duncan C
    Nov 13 '20 at 14:17

As written in the comments, the linked projector is a DLP projector with 640x320 pixels. Of course, that is expensive. It is a complete pixel display, which can display anything (with the max resolution of 640x320). That is way more, than the projector watches.

The watches often use one of two possibilities:

  • A bright 7 segment LED display, which is projected to the wall via a lens. The seven segment display needs to be bright enough, depending on the intended brightness of the projection and how big the projected image should be.

  • An LCD display, which is illuminated from behind by a bright LED. That is then also projected to the wall with a lens. I would guess, that this is, what the linked watch is doing.

How to build that yourself? You can always salvage one of these watches. But when building it yourself, you should also follow one of the above possibilities. Which one depends on your requirements.

Using a standard 7 segment display will be the easiest. Though that might be not bright enough. You could look for especially bright 7 segment displays and test, if that is enough for you.

The second possibility would be more hacky. Most LCD displays, that you can buy, have a LED lit plane in the back as a backlight. You would need to remove that plane, so that the display gets transparent. Also you most likely would need to rotate the polarizing filter on the top of the LCD, because as standard a driven segment of the LCD gets more opaque, while you want it to get transparent. A new filter (up to a few cm) can be salvaged from the passive 3D glasses from a movie theater.

In both cases you install the display inside a tube together with a fitting lens. Look, what you can get from your location and then experiment with it.

can you link to parts

No, we are not really doing that here, because that is really dependent on your location, on your price- and other requirements. Also such part suggestions are usually very fast outdated. But you can look at the electronics shops, that you have at your location and search there for the general description of the parts (for example "7 segment display").

  • What material are you salvaging from 3d glasses? What sort of lense would I want? I was mostly asking about links to parts as a reference not necessarily a shopping list. I don't know how meaningful of a conversation we can have about this with talking about specific parts.
    – Bbb
    Nov 13 '20 at 16:48
  • As reference: search at amazon for "7 segment display" and for "convex lens". I have no other reference for you. What I described is only an idea for the general concept. You still have to design the project itself. Google for unterstanding simple optics with lenses and decide based on that, what lens you need. Similar with the display. There you can also choose beween ready to use modules or the pure displays, which you then would need to drive with extra chips.
    – chrisl
    Nov 13 '20 at 18:16
  • For the 3D glasses: I mean the cheap 3D glasses, that you get at the movie theater for 1 or 2€. The ones with just a thin foil instead of glas lenses. Like this one These are polarizing filters, which you can cut out of the frame. But you can also buy polarizing filters.
    – chrisl
    Nov 13 '20 at 18:20

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