Solar Powered LED Twinkling Star in a Jar

Here's a nifty little Christmas gift I made up for my daughter. It's quick and easy to throw together, and looks rather nice. It's pretty much a sun jar with a couple of modifications, I used a star shaped LED from a string of Christmas lights, and modified the circuit a little so that instead of a steady light, it twinkles softly.

Here's a short video so you can see how it looks. It is more noticeable in person, but you should get the general idea.

***UPDATE 5/4/10:  If you make your own star in a jar and post it in the comments, I'll send you a patch!***

Step 1: Gather Your Materials

Materials you will need:

Solar garden light
LED candle (see notes on step 4)
Star shaped LED Christmas lights (or make your own shape)
Glass jar with a wide lid (this jar is from some marshmallow fluff)
Tin foil (not required, but looks nice)

Tools you will need:

Needle nosed pliers
Wire cutters
Hot glue and glue gun
Epoxy (E6000 is the best!)
Scissors
Solder and soldering iron
Small flathead screwdriver

Step 2: Prepare the Garden Light

I've done a lot of messing around with these, and I've found that every single one of them is different, so I don't know exactly what your experience will be like. The light I chose to use was an old one I've had for a while, but I picked it because I knew it would be easy to work with. The plastic was pretty soft, so I could use heavy scissors to cut it. Also, I'd already removed the original light to add a blue one, so making way for the new assembly was very simple.

First, you'll want to get rid of everything but the top of the light, where the circuit lives. Some brands are easier to get to than others, you may need a screwdriver or a box knife, or even a dremel tool at this point to get it out.

The really important part here is to make sure you don't damage the circuitboard, the wires, or the solar panel. Also, make sure to keep the battery holder intact.

Once everything is out and ready, set it aside. We'll come back to it in a moment.

Step 3: Prepare the Lid

The inside of the lid is where all the bits go. Carve a couple of holes in the lid where you can put the wires through. You'll need to desolder the wires from the solar panel, and reattach them after you've fed them through the lid. Make sure you remember which is positive and which is negative!

I like to use a dab of hot glue to hold things in place while I work. The hot glue isn't a permanent thing though, as it is very temperature sensitive. Once everything is in place, use your epoxy to make things permanent, especially the holes you made in the lid! That will keep the water out if you use this outdoors.

There are more detailed, step by step instructions in the image notes below.

Step 4: Prepare the LED Candle

When you go to get a candle for this purpose, you have to be kind of careful. There's no way to tell whether you're buying one that has a circuit board that makes the LED flicker, or one that has one of those LEDs that flicker all by themselves. If you're going to be making your own shape rather than using a star like the one I used, then it won't matter since you can just use the flickery LED from the candle, or buy one of a different color online.

I had to try four different brands of LED candle before I found one with a flicker circuit (if anyone knows how to make one of these without all that tedious mucking about with IC chips, I would dearly like to know) at my local grocery outlet.

Pry it all apart with a screwdriver, remove the circuit board, and extract the old LED.

Step 5: Prepare the Star LED

Simple step here, get the LED out of the string of lights (or use one of the replacement bulbs, as I did).

Fold down the wires, and just pull the LED right out. Since the LED came apart from the star, I put a dab of hot glue in the hole and shoved the LED back in.

Step 6: Put the Star in the Flicker Circuit

It may seem redundant and obvious, but make sure you keep positive and negative sorted out!

Heat up the solder on the tabs of the flicker circuit, and insert your LED. Add a little more solder just to make sure everything stays in place, but don't connect any of the four tabs to each other (except the positive wire to the positive LED lead, it's supposed to be like that).

Step 7: Attach the Flicker Circuit to the Garden Light

Solder the wires from the flicker circuit to the leads where the LED used to be on the garden light circuit. Remember, positive to positive, and negative to negative! There's going to be a huge mass of hot glue and epoxy all over this thing, so make sure you get it right!

Once it's all attached, put a battery in and see if it works right. If it does, pull out the hot glue and tack everything together (see the third picture below). Once that's dry, put epoxy on all the major joints and let it dry overnight.

Step 8: Tin Foil, Part One

You may want to wrap this all up in tin foil, to make it look a little nicer. Before you put any tin foil on, glob a bunch of hot glue over everthing that is exposed and metallic, except the battery terminals. This is to make sure your tin foil doesn't short anything out.

Make sure you leave a way to get back to the battery holder. I didn't, and when I went to put the nimh battery back in (I was using an alkaline for testing) I ended up having to pull off all the tin foil.

Step 9: Tin Foil, Part Two

This step is not strictly required. There are two ways you can use this light. One is the method that looks nicest, which is to flip it over at night so the star shines up though the clear glass bottom.

However, if you are lazy and absentminded like I am, you may either forget or decide not to flip it back over in the morning so the battery charges. If you crumple up a bit of foil and put it at the bottom of the jar, it reflects the light nicely, and is a simple alternative to flipping the jar over every day.

Step 10: All Finished!

Now, wrap it up, stick a bow on it, and give it to someone you love!

I hope you've enjoyed this instructable and found it useful. As always, please leave a rating or a comment or both. Let me know what you think of the idea, the instructable, my writing style, etc. If you need any clarification or help, just ask!

Also, if you make this instructable, post a picture in the comments and I'll send you a DIY patch!