Introduction: Solar Powered Light-Graffiti Projector

Picture of Solar Powered Light-Graffiti Projector

I recently read this interesting article in Wired magazine about "Light-Graffiti Hackers". The Problem with light-graffities is that you need a power source to make them permanent, so you usually can't put them everywhere you like. So I thought about making a small solar powered Light-Graffiti Projector that can be mounted nearly everywhere. The problem is that it mustn't be very expensive in case it gets stolen, confiscated or whatever. First I thought about using a cheap laser pointer as a projector source, but you can't make these caps to display different symbol by yourself. They are called "Holographic Optical Elements" and they are very expensive in production if you only need one with your special image (tell me if you know how to make them by your own). So I decided to use a LED. I also noticed that solar panels are still very expensive, but then I found one of these solar powered garden lights for only 5 Euros and transformed it into a "Solar Powered Light-Graffiti Projector".

Step 1: This Is What You Need

Picture of This Is What You Need

One solar powered garden lamp for about 5 Euros. Found mine at the German electronics supply store "Conrad". One optic lens to focus the projected image. One ultra bright LED, the one in the garden light is usually to dim. I took a red one. Two small pipes of aluminium or plastics, each about 5 cm in length, that fit into another. The outer tube should have the same radius as the lens.
The image you want to project on the wall, printed on a transparency film. You should print it with a high resolution because the image is magnified.

Step 2: Disassemble Garden Lamp

Picture of Disassemble Garden Lamp

First of all you have to remove everything except the top of the garden light which houses the solar panel and the LED. After this replace the LED with the brighter one.

Step 3: Add Smaller Tube

Picture of Add Smaller Tube

Now take some hot glue and mount the LED at one end of the smaller tube. On the other end you have to attach the transparency film.

Step 4: Mount Bigger Tube

Picture of Mount Bigger Tube

Finally slide the bigger tube on the smaller one and attach the lens on the bigger tube with some glue. If you like you can attach a stand like a tripod, as I did. You also should put some hot glue on all holes to make your projector weatherproof.

Step 5: Final Projector

Picture of Final Projector

Now you only need to find a place where you can put it. You should carefully choose a place with a lot of sunlight. The advantage of the used solar garden light is that it only lights up at night when the graffiti can be seen. I've tested mine on the balcony the last days but I have to say that the sun here in winter is too weak to give the energy for a whole night of projection. Perhaps I should wait till spring until I expose my projector to the street. So watch out, perhaps you will see one of these someday in Munich.


Phillistine (author)2014-06-02

Cool idea!

ilpug (author)2012-04-08

Oh man, you should be in GRL... I love this!

ANDY! (author)2011-11-11

Sweet project.

shadow07 (author)2008-05-05

That's a really good idea. I have to ask though. Does the solar panel have to face the sun directly for it to be efficient??

911TargaSC (author)shadow072008-12-25

shadow07, I havent experimented with these small panels much though I do have some solar walkway lights (currently buried underneath the snow = not very effective). From what I have read about solar water heating panels, and should be true for all solar panels, is generally facing your panel south and with a little bit of tip toward the south (instead of the panel looking straight up) you are going to get just about the same results (within 10%) of getting a solar contractor to come out to your house and align it for the 100% best angle.

paulezra (author)911TargaSC2009-01-15

south facing for northern hem, north facing for southern

911TargaSC (author)paulezra2009-01-15

thanks. good catch. I guess I was thinking too locally. these here "internets" are kind of a big deal ALL OVER the world, huh? ; )

paulezra (author)911TargaSC2009-01-15

yeh can't blame you for forgetting. i don't seem to be able to get the lens. so none of this information is helpful to the southern hemisphere. but thats no fault of the people here, its the damn lack of people in Australia and lack of demand for a simple convex glass lens.

brexford (author)paulezra2011-10-31

Go to any pharmacy and look at the 'readers' bifocals glasses...would any of them do the job? Can you not shop on the ubiquitous Internet?

RDN1 (author)shadow072008-05-06

I didn't have the chance to test it, but I think a clear sky would be sufficient. I often see these lights in the neigborhood and they are very dim in winter. I would suggest aiming for a better solar panel.

brijeshverma (author)RDN12010-10-28


paulezra (author)shadow072009-01-15

they work fine as garden lights not pointed directly at the sun, i don't see why the changes would make them work any different.

urtlesquirt (author)2011-05-07

Dude this rocks.

harry potter rules (author)2011-04-21

does it have to be a solar lantern

letters (author)2010-12-25

What is the size of the lenses?

jakk21 (author)2009-03-21

what does RDN stand for?

tleec11b (author)jakk212010-09-16

the doods name irl is prob rodney.... now shorten it rdni or rdn1.. thats my guess

lucius108 (author)jakk212009-07-05

its the dudes name on instructables

beehard44 (author)2009-09-28

grab one of those cheap LCD alarm clocks and remove the back layer of the LCD and put it in the tube and, DIY PROJECTOR ALARM CLOCK! get it?

themonorail (author)2009-06-10

or even just a whole telescope??

themonorail (author)2009-06-10

can i just use a lens from a telescope or something?

paulezra (author)2009-01-15

can anyone help find a supplyer of the lens in australia. or a place that will ship them to australia. thanks

911TargaSC (author)2008-12-25

This is a great project. A practical use for it could be to project your street address on to the pavement at night allowing for easier location of your hosue by the pizza guy... and we all want our pizza sooner, right? : )

Petrus1002 (author)2008-08-17

Really like this one, and very clever too! Questions though: what type of lens did you use (in milimeters, I mean) and is it convex or concave. Also, how large is the projection? What would you have to change to get a really large projection? Thanks everyone!

911TargaSC (author)Petrus10022008-12-25

Petrus, keep in mind that there are only so many lumens coming out of that LED. As you focus the image to something larger it becomes weaker. that being said, to make the image larger or smaller, experimenting with differnet lenses would be one thing, the easiest would be moving the lens closer or further away from the light source.

Eye Poker (author)2008-05-10

That looks uncannily like a Martain War Machine from War of the Worlds.

jillg (author)Eye Poker2008-11-20

thats just what i was thinking

mettaurlover (author)jillg2008-12-14

it also looks just a little bit evil...

maker12 (author)Eye Poker2008-06-10

heheheh make sure no jackalopes popup!

maker12 (author)maker122008-06-10


itsnotthenetwork (author)2008-09-16

I wonder how the transparency from a view master disk would look,

The Lone Hoot (author)2008-08-14

Cool idea and nice work! :-) I wonder if the same could be done with enough combined solar cells from old/broken garden lights to power a laser pointer to project a brighter image even farther. I'm thinking against the side of a large building. ;-)

Artificial Intelligence (author)2008-05-01

This is very cool. You can also try it with one of those RGB LEDs that has a build in microcontroller that makes it flash in various colors (Rainbow LEDs)

I like the micro controller idea I was also thinking on making a version that uses one of those cheap nokia LCDs converted to a projector of course that would take more power then your typical solar light can supply.

That's a really great idea. You can post an Instructable with that idea. I think many people would love it.

I will when I figure out how to make one transmissive the color nokia I took apart didn't show much promise blocked way too much light after ripping the back off so maybe I might look into those cheap DVD players.

What are you planning to use as the light source. some LEDs?

OK, good luck.

agreed! that is brilliant! I am going to work on that. Microprojectors are my new project. And If I can make them cheap enough, i can scatter them around town. For now these static image projectors will have to do, though.

Cool. When you've made it, send a link to me!


Sorry! I use certain abbreviations without thinking. One question mark would have sufficed, though :) No problem!*

Tip: a colour changing led will not work with most solar powered garden lights. I tried and found out there is the following problem: most solar lights use only one battery cell and convert the 1,2 V to a higher voltage with a switching circuit. The higher voltage might just be enough for a colour changing led, but the problem remains the output voltage is not stabilised and the led is constantly being reset and does not get passed it's starting colour. So, you would pobably build your own system working at a stable voltage adjusted to the led used.

you're right, but there are many different color changing LEDs out there. Some requires 3V and some requires 5V. maybe it would be possible to find a suitable LED.

I am afraid the colour changing still gets reset each time the voltage goes down (which it does at high frequency). I expect you will need to stabilise the voltage first. That can be done of course with some extra parts.

shimniok (author)2008-06-15

You might try for the lenses. I got a package of lenses from them for a small amount. They also have LEDs and various other electronics. -Michael

shimniok (author)shimniok2008-06-15

PS: they also have solar cells + charger circuits & leds for < $5 US ...

masynmachien (author)2008-05-13

I love it! Inspired by instructables like "Robot Invasion" and several solar light hacks I have been making several different kinds of "robots" from solar powered garden lights. Your instructable gives these solar light hacks a great new function and at the same time it looks real cool itself. Very inspiring.

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