Fiber Optic and LED Minature Garden Light

This project uses LEDs and fiber optics to light up a tiny garden full of flowers, leaves and grass. The box is built from acrylic sheet, it runs on a 9 volt battery and has a sliding door on the bottom for easy battery access.

I've been collecting up little plastic flower beads for a long time. The matte finish has a bit of a glow to it in ordinary daylight so I thought they would be perfect lit up. The fiber optic cable was a semi impulse buy (I've wanted to play with fiber optic since I was a little kid and my parents got me one of those glowing flashlights that were more effective at poking eyes out than anything.) The electronics are easy to get at any Radio Shack (though ordering them in is much, much cheaper) and the rest of it can be rounded up with a trip to the craft store.

I'm really proud of the way the battery access is set up. I've been working on a way to do that for a long time. The wiring is all wrapped in shrink tubing.

The finished light has a 3 by 3 inch base, and looks great on a bookshelf (where mine is) and would be fantastic in a little girl princess room as a nightlight.

Step 1: Materials and Tools List

Materials

- about 6 by 12 inches of 1/16 inch thick clear acrylic sheet
- black spraypaint
- 1 minute epoxy (be sure it's a plastic and metal friendly version)
- a switch - anything small enough to fit on a side wall
- a 9 volt battery
- a 9 volt battery snap
- 14 3mm LEDs - I used white
- a resistor appropriate to the LEDs you're using - this site is super helpful: http://led.linear1.org/led.wiz
- a few feet of 1/16 inch black shrink tubing (in the electrical department if you've never used it)
- around a foot of 1/8 inch clear plastic shrink tubing
- about a foot of 12 strand plastic fiber optic
- 24 gauge wire (mine is craft wire from wal-mart, use whatever you like)
- plastic flowers and leaves - I used about 35 flowers and 50 leaves
- plastic lacing in various greens and yellows - this is what 'lanyards' are made of, you know, the classic summer camp craft stuff

Tools:

- heat gun
- needle nose pliers and wire cutters
- something to drill holes and something to drill into (to protect your workspace)
- something to cut acrylic sheet - this is thin, so an 'acrylic cutter' that scores and snaps will work - I use a dremel to drill holes and cut the hole for the switch
- masking tape

Step 2: Cut the Acrylic Sheet

I included a file with the appropriate pieces. Cut down your sheet of acrylic to the sizes listed, then spray paint one side of each. I didn't paint the piece everything attaches to, but you can if you want. The painted side of the sheets needs to be the INSIDE of the box.

Step 3: Make the Flower Stems

Cut a chunk of the fiber optic cable - 3 to 4 inches, and pull the strands out of the tube.

Place a small pieces of masking tape over the back of each flower.

Use a pin or piece of wire to poke a tiny hole through the tape that goes through the center of the flower.

Push the fiber optic cable end just through the hole.

Put a drop of the 1 minute epoxy into the center of the flower to hold the cable in place.

When it's hardened (around 10 minutes or so) peel off the tape.

Do this to all of the flowers you plan to use.

Step 4: Make the Leaf Stems

Cut a 5 or 6 inch piece of wire.

Fold it in half.

Thread a leaf onto it.

Give it a twist or two to hold it together.

Thread on a short piece of shrink tubing and shrink it.

Keep adding leaves and tubing this way until you like it. Leave plenty of un-leaved wire at the end, but finish it all in shrink tubing.

Make enough of these so that there is one leaf stem for every 2 to 3 flowers.

Step 5: Attach the Flowers and Leaves to LEDs

Group a couple flowers (3 worked the best for me) and one flower stem.

Arrange them together so that the heights look good to you.

Cut them all off evenly.

Thread them into the clear shrink tubing a bit. The goal is to find a length of tube that supports them and lets them move around a bit.

Cut the clear tube off with about 1/4 to 3/8 inch extra.

Push the bulb of an LED into the end of the tube. Fidget with it until the LED is solidly in the tube and the fiber optic cables touch it.

Heat shrink it together. BE CAREFUL. The fiber optic is a thermoplastic and will melt with heat. Try to move the heat gun around as much as possible and focus the heat toward the bottom.

Repeat this until all of your flowers and leaves are used up. I ended up with 10 groups.

Step 6: Make the Grass

Cut lengths of the lanyard plastic that are around 4 inches long.

Group them in 4 to 7 strand bundles.

Use a short piece of wire to twist them together. This wire will push through the base to support the grass.

Wrap another piece of wire around the whole group folded in half to keep the strands upright (look at the pictures - it's easier to see than to explain).

Repeat this until you have about 24 groups.

Step 7: Glue Up the Acrylic Box

You have 4 pairs of plastic pieces for the wall of the box. A pair is one large piece, and one that is shorter and slightly narrower. Glue them so that they are centered horizontally and line up at the bottom. The epoxy works well for this. You want the masked side out - glue the painted sides together.

When they're set up you'll need to cut a hole in one pair for the switch. Mark it out - close to the bottom, not too close the the end of the piece. Drill the corners of the switch then cut between them (I used a dremel with cutting wheels and bits.)

SAFTEY NOTE:
This is a time to really, really use your safety glasses. Plastic sends small sharp pieces flying around when it's drilled or cut this way. You only have 2 eyes, and even if you only blind one of them you're going to have a hard time not running into things.

Two sets are longer and two sets are shorter. This is so that they fit up to make a proper box. You need to glue them together with the epoxy. Tape them together while it sets up, and tape it all to the square ring to be sure it sets up nice and square (again with the pictures - visuals make more sense here.)

The square 'ring' and two 'U shaped' pieces form the bottom. Glue the narrow 'U' onto the square. Then glue the wider 'U' on top of that. This forms a track for the battery door to run in. The other square piece is a door, and the narrow strip is the handle. Glue the handle to the door.

Once the bottom is set up glue the sides to the bottom. This will form the box, and the panel with the flowers attached will drop into the top.

Step 8: Attaching the Flowers and Grass

On your remaining plastic decide where you'd like the flowers to go. Spread them out as equally as you can. Drill pairs of holes for the LED legs to go though, keeping in mind a 'route' for the wiring. All of the positives need to connect, and all of the negatives need to connect. I added 4 LEDs without flowers to help brighten it up.

Once those are drilled fill in the board with single holes for the grass. Again spread them out, and make sure there's a row of grass around the outside edge to camoflauge any visible LEDs.

Push one LED through the panel. On the bottom fold the wires over in the direction of the next LED you plan to wire.

Cut two lengths of wire long enough to trace the entire patch of the LED wires.

Leaving a short tail, twist one of them around the positive wire of the LED on the panel. Cut a piece of the black shrink tubing long enough to reach from there to the next LED (plus a bit, because it will shrink along the length of the wire as well.) Thread the tube on and shrink it. Do the same to the negative side. Trim off any extra LED wire. Add another LED and keep wiring the same way. Connect up all of your LEDS being REALLY careful to keep all positives connected to positives and negatives connected to negatives.

At the end of the positive wire cut it down to an inch or so, then add shrink tube and a resistor.


Push the grass pieces through their holes, fold over the wire on the back and secure it with a bit more epoxy.

*All images are the BOTTOM of the panel.*

Step 9: Final Wiring

Attach the positive resistor end to one terminal of the switch - add a piece of wire and some shrink tubing to do it.

Connect the other terminal of the switch to the positive side of the battery snap and cover it in shrink tubing.

Connect the negative wire from the panel to the negative wire from the battery snap and cover it in shrink tube.

The shrink tubing ensures that the positive and negative never touch, and it makes for a nice, finished look.

Step 10: Final Step

Drop the panel full of flowers and grass into the top of the box. You'll probably want to glue it into place for security.

Turn it on and put it somewhere awesome.