Cheap Projector Tells Time, Invades Space

Building a video projector isn’t something that most people do casually, but [Dominic Buchstaller] isn’t most people. As part of an ongoing street art  project, he built a rather neat scrap video projector/bedside lamp/clock device he calls Great Balls of Fire. It is made from a Nokia cell phone screen and a small projector mechanism, mounted inside a frosted glass light sphere.

One of the most interesting parts of the build is the projector mechanism. Rather than build one from scratch or tear apart an expensive Pico projector, [Dominic] found another source: a cheap car logo projector from eBay. These are designed to show a car manufacturer logo on the ground when you open your car door. It came with all of the parts he needed, including an LED light source and optics. He tore that apart and replaced the car logo with the phone screen, creating a very cheap projector. It isn’t that bright, but it is bright enough that when he mounted it inside the glass sphere, it could project the time and the odd space invader. It’s a great example of how sometimes it makes sense to look for a cheap solution rather than a free one: buying the car logo projector saved him a lot of hassle in building the optics. [Dominic] was also responsible for this awesome old-school tube radio hack, where he replaced the guts of an old radio with an internet radio player.

14 thoughts on “Cheap Projector Tells Time, Invades Space

  1. He complains about giant pixels and low resolution but throws most of the pixels/resolution away!
    What he really needs is to get some better optics and project the whole LCD not just the center 30% or so of it.

    1. … true! However, projecting the whole image plane requies larger lenses, etc. that I don’t know how to source for cheap. A low cost, retina type 1cmx1cm gray scale display would be perfect :)

      1. As a matter of fact the best way to source one of those high density displays is buying an old projector. Each projector has 3 tiny (about 3/4 inch) LCD screens and lots of optics. A projector with no bulb can be found on ebay for $10 or $20. Now directly handling the small LCD screen is something I haven’t done yet (for he little project I was experimenting with I used the whole electronics from the projector)

  2. It’s pretty cool, it’s similar to how imax or CAVE vr systems work. You are just looking at it from the outside. If he used a higher resolution lcd and an arm based dev board he could create a very unique graphics display.

  3. A heat mirror (reflective at IR frequencies and transparent at visible frequencies) is available from Edmund Scientific. Could add this to your more intense LED source and avoid burning the LCD….
    Not sure where to find these mirrors in surplus gear… Anyone know ?

  4. In a projector the condenser is the lens assembly which takes the light from the light source, which is generally radiating outward in a spherical pattern, and directs as much of it as possible all in the same direction through the slide or LCD. It’s generally two very thick convex lenses facing each other.

  5. A CRT wouldn’t be bright enough except in total darkness. But a LCD viewfinder from a camcorder will with enough light. It will be small enough to fit where the car logos go in those LED lights.
    Go thru those 12volt lights available, lots of styles low prices.

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