Build a solar powered flashlight in an Altoids tin for next to nothing. Contains high efficiency leds. Completely self powered. Uses a solar panel, a rechargeable battery, 5 extremely bright white leds, and a toggle switch. Everything fits into your Altoids tin. I built this to use as headlights on my longboard.
-1 Solar powered garden light (I bought one of these for $4.88 at the register http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?jspStoreDir=hdus&catalogId=10053&productId=202080419&navFlow=3&keyword=873046003508
included was a rechargeable battery, a solar panel, and an led.
-4 Recycled key chain leds (or plain leds http://www.radioshack.com/product/index.jsp?productId=3060980 $3.98
-1 Toggle Switch http://www.radioshack.com/product/index.jsp?productId=2062497 $3
-Altoids candy $3 (I used a switch from an older diy project)
-Rare earth magnets (optional)
-Wire (you should have this already)
-Electrical tape (you should have this already as well)
Total Price using recycled parts = free
Total gross price = $14.86
-Brass sponge (optional)
-Dremel (you can use a drill if you don't have one)
-Hot glue gun
-Wire cutter / stripper
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Step 1: Freeze the Altoids
Take the Altoids tin, open it up, empty it out, fill it up with (cold) water, close it, and place it in the freezer. I left mine in for around 4 hours.
This makes it so when you drill holes in it, it does not dent the can.
Step 2: Take Apart the Lamp
While the tin is freezing. Take apart you're garden lamp. Everything should unscrew, you may have to pry a screw driver underneath the solar panel and then slide it along its perimeter being careful not to break it.
Step 3: Soldering the Leds
while your can is (still) freezing take advantage of this time by soldering up your leds.
I soldered parallel so they would all be the same brightness, this means all the positive legs should be connected to each other and all the negative legs should be connected to each other. This does take longer but its worth it.
Also desolder the solar panel, and the switch or sensor that it comes with (you can leave the battery connected or make a wire connected to it in a holder if you have to move it), it helps to tag the wires with a piece of paper just in case.
Don't forget to desolder the led from the solar panel and mark that as well, with an extra led check which side is positive and which side is negative on the panel, remember to mark this some how! (I wrote it on paper)
Step 4: Drill Holes
You can now take the can out of the freezer.
First I used a sharpie to mark a guesstimate of where I was going to cut.
Then I cut the holes small, and checked if the component would fit, if not I drilled bigger.
-repeat until all holes are drilled
-Make sure you wear some kind of eye protection as this is still metal.
(I used a paid of sunglasses as it was all I had)
-Remember you can always drill bigger but you cannot make your holes smaller again.
Step 5: Place Components and Glue.
Make sure you're box is unfrozen, It it is not, to speed up the thawing process let warm water run from the sink and place it under.
First bring the two wires up and re solder them to the panel. Proceeding that, put two small pieces of electrical tape over where the exposed wire is in order to prevent shorting. After that apply hot glue to the underside of the panel (where the wires were soldered), and mount the panel to the can. After the glue has dried apply extra glue around the wires through the holes (just in case anything does happen).
Put the switch in place and solder that to the board as well.
With the led set you just made take a red wire and solder that to the positive side of where the old positive side was of the old led on the board.
With a black wire do the same for the negative.
apply electrical tape throughout the inside of the can to prevent shorting.
After that is done place all the leds in position on the can and hot glue them in place (if necessary remove the lid) make sure no there are no contacting led legs use extra hot glue to prevent this fro happening or use electrical tape.
If you have magnets and you did not glue them already do it now.
place all you're components inside the tin and glue away, I also glues my tin shut
Step 6: Enjoy and Show It Off
Possible uses include:
-Extra Credit in environmental class
-Emergency car flashlight
or just the feeling of satisfaction
Take pictures and comment if you do anything fun with it.
Read more of my projects at