This is basic instructions on how to build a portable image projector that uses a green laser instead of normal light. The laser permits images to be cast great distances, and doesn't require focusing - it's always in focus.

This particular design is simple in order, more for the sake of keeping my short attention span on track for long enough to actually get this finished!

Let me know if I've missed some detail and I'll correct it.

For more photos see flickr page

Warning: Even a low power laser can cause permanent eye damage. Always wear safety glasses and never point at people, animals, or police helicopters!

Step 1: Materials and Tools

Picture of Materials and Tools
This method describes absolute basics using lesser quality optics and low power green laser.

This guide shows the set-up for slides made from overhead transparencies.

I will use the Dinkle rails and polymorph pellets.

Materials Required:

  • Green laser module 10mW+
  • 1 solid length of wood (~90cm)
  • polymorph pellets (or a willingness to create lens holders from wood, plastic, etc)
  • concave and convex lens. You can get these from old disposable cameras which camera shops will throw out by the dozens.
  • Hardware for attaching rail to wood (bolts or screws, depending on method).

Optional Materials:

Tools required:

  • Drill
  • Jigsaw or handsaw
  • Hole making bits for drill (if using wood to create lens holders)


I will use the Dinkle rails for this instruction simply because they make alignment so much easier. They also allow a great degree of modularity - being able to swap different lasers, lens, etc in and out quickly.
1-40 of 145Next »
SuperTech-IT7 months ago

LOL - don't take this through airport security - unless freedom is something you've become bored with.

nikosb8 months ago

Regarding the lens obtained from the view finder of a disposable camera. Those lenses are inverted Galilean type, which includes a concave lens and a convex lens. From the photos it seems that you are using only the concave lens from a viewfinder, but not the convex lens. Is that correct?

nikosb8 months ago

What specs should the focus lens have? Would one like this work:


mycroftxxx7 years ago
Nice project. If you're going to eventually try using the laser to illuminate a TFT lcd, you might want to go ahead and try your hand at blending lasers to get a "white" beam out to your LCD. How do you blend lasers? Easy! With a prism, you can presumably mount your three lasers so that they each enter the prism at different angles and emerge congruently. The easiest method I can conceive of doing this by is to shine a little sunlight into the normally non-emitting face of the prism, then they sliding your lasers back and forth through the rainbow until the color emitted from the prism matches the color of the laser. Then, cut off the source of sunlight and adjust your lasers back and forth until your emitted "white" beam (in quotes because it won't be) is as small and bright as possible. Voila! bright and power-efficient light source for your projector that needs very little focusing! Please note: Typed out like this, this process looks easy. If it were actually so, cigarette-pack sized projectors that can throw images many feet would probably be available for $125-300. I have never done this, know little if anything about the optics involved, and have only seen a few laboratory attempts at making this work that succeeded with a purely multilaser lightsource. If you pulled this modification to your current plans off, consider yourself a king amongst hackers.
nikosb mycroftxxx8 months ago

You can use dichroic filter for combining RGB lasers.

echo_anomie (author)  mycroftxxx7 years ago
Interesting idea. I know you can split a beam with a triangle prism, but wondered if you could merge two laser sources into one, say a green and a blue laser, and then merge that with a red laser via another triangle prism. Purely a theoretical idea though, but must be tried one day when I can afford one of those blue lasers. The plans published in this instructable are very basic indeed - I've experimented with a few other things but thought it best to keep this article strictly aimed at fundamentals with only the laser being the main burden of cost. I love the idea of a cigarette sized projector though - it'd be a worthwhile challenge to get it down that small :)
Well, if you want to experiment with a "blu" laser now, repair parts for the ps3 can be found for 40-50USD via this ebay search. There may be some other way to get the blu-ray laser diode more cheaply still, but it's a start. (FYI, for ebaying a given piece of technology, I find that searching "[technology] (broken, parts)" tends to yield an avalanche of links. Putting multiple comma-separated items in parenthesis will cause ebay to do an OR search for all the included terms.)
Or you can get a ps3 assembly (including a violet 405nm laser diode) for $25, and all the knowledge you need to use it and more, at http://www.laserpointerforums.com
:) its a great place. and PLEASE DO NOT buy from wicked lasers. come on LPF and you will see why...
echo_anomie (author)  BlueFusion7 years ago
Thanks for the advice. I've got the feeling that my 100mW (won on ebay) isn't actually a 100mW (it can't burn pvc, or etch dark card at all). Is novalasers good?
Novalasers are exceptionally good, but if you want real power try Optotronics. Now they have some LEET lasers. If you come on LPF, there are people who have laser power meters to whom you can send your laser, if you pay postage they will test it for you and provide a report. You may be able to use this to take it up with the ebay seller, but on the forums eBay lasers are known to be a gamble at best. it wasn't a seller called zonestealth was it? he's no good with lasers. I have personally a ~185mW red laser... it's soo much fun. it can even sting unsharpied skin... match lights, burns plastic, everything.
I know Evans and Sutherland (Now Rockwell Collins) is working on an RGB laser projector. Whatever the problem are with the technology, they're tough ones.
RGB animation lasers are nothing new. Just difficult to DIY. You can buy a 1W combined (500mW red, 300 green, 200 blue) laser scanner, computer interface and software to put together amazing presentations. IF, and it's a big IF, you have a spare $4000. I really don't think a DIY one would be any cheaper. Regardless I intend to try too :P
I'm not sure what their difficulties were, but their laser projector's not good enough to replace our current system. Maybe grain problems during low luminance scenarios?
A RGB animation projector offers such things as 1,000,000:1 or greater contrast ratios, as light is only projected where needed, the difficulty is scanners or 'galvos' that can scan fast enough to work as a projector at like, 30 FPS. (frames per second) Also, the equipment (DAC, lasers, amps, galvos) is still relatively expensive. and yes, they are awesome. try searching youtube for 'RGB laser show' or similar.
echo_anomie (author)  BlueFusion7 years ago
That would be an awesome projector :)
echo_anomie (author)  mycroftxxx7 years ago
Searching that ebay link - another interesting link:
blue ray phaser
echo_anomie (author)  mycroftxxx7 years ago
Hmm, thanks for the idea and links.
When I saw this the projector mixing three lasers was the first thing that came to mind. Excellent instructable!
mgysgthath6 years ago
SO essentially you're just piping the beam through the slide, after diffusing it with the lens? I've got a 450mW 532nm laser and I'm thinking of trying this one out. I've already got some convex lenses. I've got ready access to plenty of LCD screens and I'm wondering what you're thinking? Pipe a video signal through the LCD and instead of a regular backlight, use the laser? I think with 450mW even with the light absorption, it might work decent.
you know what would be cool...
get a green one, a blue, and a red one all together and have full color laser projection.

Would that work?

That's exactly what I was thinking too! Already wondering where I can scrounge parts from....
I reaaaalllly wonder if this would work
Well my RPL-425 is for sale, if anyone wants a 433mW professional green laser.
prem19671 year ago
is it posible to combine three color of lasers ( RGB ) to get a white beam..?
nikosb prem19678 months ago

I am actually interested in the the same idea, combining RGB to get a white beam and use the white beam for the image projection. Did you try it and did it work?

Pirat1 year ago

Would you suggest any link from ebay for a laser compatible with this project? There seems to be a lot of 500mw with very different price tags and specs.

itge133 years ago
that's the first instructable i comment. i have to say it.. AWESOME :)
how can i make it colored?
Lol. Picture 3 looks like a bomb
It sure does.  ;-) Bomb-like insides, plus a conservative looking briefcase on the outside... I think this just adds to its awesomeness!  Very stylish.  I sort of imagine the theme from Mission Impossible being played while this thing is in use.
ALogan974 years ago
Would one of those small, red pet toy-type lasers work?
any laser would work, but obviously the lower power the laser, the dimmer it would be and the shorter range it would have. echo_anomie here uses a 100mW laser, but states under materials that 10mW+ is needed. 5mW is considered the limit for "safe" lasers, so you can expect a pet laser would be even less than that.
In short, yes a pet laser would work, but it would have a range of probably a few cm in a dark room
Foxfur4 years ago
Has anyone tried projecting using Viewmaster discs? It might be cool. I wish I had my old 'Land of the Lost' discs... I miss that show.
sergutaya4 years ago
cool !!!
baruc4 years ago
hi, i like so much your project, but you know what kind of eye protection do I even need? i have some lens and a 30mW green laser. Thx
biolethal baruc4 years ago
baruc biolethal4 years ago
thx, i'll try to find these here in mexico. Thx
tinkerman924 years ago
i dont know if someone mentiond this already or not but if u put a dish of living organisms in that they wouldnt b living for long. cool tho
now you watch in film viewing
1-40 of 145Next »