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.

Cool idea!

ilpug3 years ago
Oh man, you should be in GRL... I love this!
ANDY!3 years ago
Sweet project.
shadow077 years ago
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??
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.
south facing for northern hem, north facing for southern
thanks. good catch. I guess I was thinking too locally. these here "internets" are kind of a big deal ALL OVER the world, huh? ; )
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.
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)  shadow077 years ago
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.
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.
urtlesquirt4 years ago
Dude this rocks.
does it have to be a solar lantern
letters4 years ago
What is the size of the lenses?
jakk216 years ago
what does RDN stand for?
tleec11b jakk214 years ago
the doods name irl is prob rodney.... now shorten it rdni or rdn1.. thats my guess
its the dudes name on instructables
beehard445 years ago
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?
themonorail6 years ago
or even just a whole telescope??
themonorail6 years ago
can i just use a lens from a telescope or something?
paulezra6 years ago
can anyone help find a supplyer of the lens in australia. or a place that will ship them to australia. thanks
911TargaSC6 years ago
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? : )
Petrus10027 years ago
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!
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.
mihevic6 years ago
Eye Poker7 years ago
That looks uncannily like a Martain War Machine from War of the Worlds.
jillg Eye Poker6 years ago
thats just what i was thinking
it also looks just a little bit evil...
heheheh make sure no jackalopes popup!
maker12 maker127 years ago
I wonder how the transparency from a view master disk would look,

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. ;-)
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.
shimniok7 years ago
You might try http://allelectronics.com/ for the lenses. I got a package of lenses from them for a small amount. They also have LEDs and various other electronics. -Michael
PS: they also have solar cells + charger circuits & leds for < $5 US ...
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.
it is mr hanky! lol robo pooh/poop
Robin877 years ago
I really like the idea and I'd really like to try it myself, but could you please be more precise about where you got the lense from and which LED suits best. Thanks Robin Germany
What kind of lens do I need? convex vs. concave. Also, how far away will this display the image?
yoitspoe7 years ago
lol it says preishit!
Crazy. I've been working on a similar project for a little while now. I've been trying to get the price down to less than $5 each. Anyone have a good source for cheap lenses?
You can find a line of plastic lenses at OPITEC.
I suppose these are at least as good as those OPITEC uses in their kits. My own experience with their cardboard telescope shows these are reasonably good.
RDN1 (author)  masynmachien7 years ago
Wow, great, thanks for the link! I figured out that they sell lenses from a company called astromedia and the actually have an onlineshop in Germany.
I our xillion £1 shops there are packs of magnifiers of various sizes for a quid the lot, As they are plastic i guess you could cut them to fit the tube?
In a lot of cheap junk shops in the UK you can buy generic "reading glasses" between about +0.5 and +2.5 dioptre for a couple of pounds, and then you get two lenses :) My only concern would be given the current trend for frame shapes the lenses are unlikely to be circular, but it could well be a cheap source or reasonable quality small lenses. Alternatively see toy shops (do you have ELC or an equivalent?) for small kids hand lenses.
Kiteman PKM7 years ago
We just got a bunch of low-magnification cardboard binoculars at school (they're going to be prizes, I think) - it's a pack of 30 (which makes 120 lenses), cost around a fiver, yet the lenses seem remarkably clear.
30 for a fiver? That's cheap. The best deal I've found so far is a dozen for $8 with another $7 for shipping.
It's an educational supplier - we don't pay VAT, and maybe their margins are slimmer?
They're not super-high quality, but try going by a local pharmacy that does photo developing & ask them for some used disposable cameras ( or camera shells). They'll often give them to you if you tell them it for a science project. (Science, engineering, they won't know the difference :P ) Plus, you can get useful/fun giant capacitors out of them too.
Aerospaced7 years ago

See if you can get your hands on this book. It has a section on making your on Holographic Optical Elements. But again still might be more expensive than you whish .
It's definitely DIY-doable... I did some basement holography as a teenager lo these many years ago. Getting set up would cost some money (not a ton, but you need simple photographic darkroom equipment, a sand table for isolation, and some optics) but the individual elements are cheap to make. These days you could make computer-generated ones, even.
This link doesn't work.
Try this
zofenluder7 years ago
Comment only useful for people living in Austria:
für alle in Österreich:
Baumax hat noch bis 18.5. eine aktion auf diese Gartenleuchten!
Just bought one of those and took it apart. It should work, if you do nothing except changing the led to the described projector. I thought about installing a better solar panel, so I tried some more deconstruction. Well, the whole part with the solar panel and the photo resistor is somehow glued in the casing, causing that I busted it, trying to release those parts. At least I got the main circuit now, so I can rebuild the whole thing with better parts. And 3 Euros is not to expensive. Anyway - I can ONLY recommend this thing for people wanting to build this projector very basic or to people looking for the main circuit.
[edit] also I just realised, that this circuit would work without a photo resistor. So I only need a new solar panel. Has anybody expirience with that? Could I just pick a random solar panel or are the specificacions (especially the voltage) important?
pretty cool what is 5 Euros in u.s. dollars? i've got to try it
10 bucks.
cbergeron7 years ago
If you go with the microcontroller idea, you could make the LED blink out random phrases in morse code, or binary, or something. Couple this idea with Geo caching and you could create some neat puzzles. You could couple cryptography / rudimentary puzzles with hiking, etc... the possibilities are numerous.
This is a great hack and certainly better than a throwie! If you look around you can usually find solar garden lights on sale somewhere for a few dollars or less.
johnpwiles7 years ago
This is cool. Think I'll do my house number so it will show at night. Makes it easier for party goers to find my house for those late night parties.
anerudhan7 years ago
Any idea to increase the range other than using a higher power lens....?
Cool, I also something i think on wooster colective, its a set up of tiny collored mirrors and when the street lights come on they reflect on a wall
this is great, you can make it cheaply enough so you can just leave it, and see how long it takes someone to find it it could be a long time if you hide it right
RDN1 (author) 7 years ago
After searching for a better solar panel I found this here:
IKEA SKINA Light stick/ chain 5 bulbs, outdoor, solar
The price is $19.99 in the US and 15 Euros in Europe.
You can't see the panel on the page but I bought one and it is 2 times bigger than the one from the garden lamp. It also supports 5 (!) LEDs, so powering one bright LED would be easy!
membrane7 years ago
I think I might try this also maybe a more powerful version with larger optics and brighter LEDs since I have some 6V and 12V solar panels on hand.
very nice, I've bought a pack of four of these lamp, without knowing what iI would do with them, I'll make one of these. what's the maximal range of this projector ?
stevie17 years ago
ha this looks like a tripod from scary movie 4!!!! :p
Omegablood7 years ago
I've made a similar project. I used a keychain photo albums. Things that I learned. The darker your environment is the better your picture will be. The more light(the brighter the light) you use to project your image the further it will go.
jongscx7 years ago
Install a flexible mount on it, something like:


And you can do guerilla installs...
RDN1 (author) 7 years ago
Hey! Thank you all for your interest. I have to admit that this project is already one year old. I just moved it to instructables because I've deleted my old web page.
As mentioned here before the biggest problems are the limited projection range, and the lack of a source for cheap lenses. Actually I got mine from a cheap led clock projector.
I also made an experiment with a cheap 4.5V laser pointer (3Euros) and the same transparency image. In a way just like this Laser-Image-Projector. But the power source is too weak. The killer projector would be to use this with a laser pointer and "Holographic Optical Elements", you know these caps you put on a laser pointer to generate hearts and small messages. Because then there would be no loss of energy due to scattered light and you wouldn't even have to use a lens. So anybody who has some ideas is welcome.

Lego man7 years ago
AHHHHHHHH....... Alien Invasion!!!!!!!!!!!!!
Excellent idea! I may be showing my ignorance here, but where did the lens come from? I live in a college town and would love to make something like this for on/near campus!
Also, what do you use for/where did the transparency film come from?
Mr. TiKi 1up7 years ago
You could buy them at office supply stores like office depot and staples.
This is pretty sweet! The only problem is the short projection... hmmm...
LinuxH4x0r7 years ago
Great idea!
Very Cool! Great Instructable! Thanks Joe
eeeXsmart7 years ago
flee20107 years ago
I actually wanted to do something similar for a car alarm LED. Wanted to flash a (/) no entry sign. Thanks for the ideas!
HarryM7 years ago
nettes Projekt. Nice work :-)
schickes projekt.
Ward_Nox7 years ago
looks kinda like one of the probes from war of the worlds
u know if you mounted it near trfic light most ppl would just think its a camera maybe even 'The Man"
Patrik7 years ago
Wow - excellent idea, and creative execution! :-)
caitlinsdad7 years ago
How far will the image clearly project? I know it will depend on the lens and lighting conditions but can this be placed far/high enough so a person can't swat it down?