Here are some ideas on how to create an elegant pendant necklace that glows gently at night. It is very easy to create and can be made inexpensively. The simple, rectangular shape adapts nicely to any look you want to create.
What's So Special
Sometimes you find a new product that sparks your imagination. When I saw these glowing light-panels I came up with all kinds of ideas. I justified buying some by using them as attention-grabbing name tags to be worn at conventions. But in the back of my mind, there were always several ideas for jewelry floating around insistently.
The light-panels might be industrial left overs (the backlights for old style alpha-numeric LCD readouts) but the gentle glow, low cost and simplicity made them very attractive as a new addition to my jewelry work.
This project is just one way of working with these fantastic little devices. I hope you take this idea and make something totally different and beautiful.
Step 1: Tools and Materials
Here's a list of items I used for this project. You will probably have most of these or something similar.
The only specialty items are the LCD-backlight and battery holder. The good news is that they are CHEAP, like about $6 combined cheap. And if you haven't tried Sugru yet, get a small sample and play.
- LCD Backlight Panel - These are the glowing panels behind old style LCD displays. A white LED lights them up with a gentle, diffused glow. I used the medium sized version from Adafruit (Item 1622). It is 0.8" wide x 3" long (23mm x 75 mm). They also have a Large 1621 and a Small 1626 version
- Coin Cell Battery- A standard 20mm coin battery (CR2032)
- Battery Holder with Switch - I wanted an on/off switch so I used the #1871 board from Adafruit. They also have a non-switched board (#1870) and a more bare-bones version (#653). Similar products for the CR1220 - 12mm coin cell batteries (1867 and 1868) are available. Sparkfun also has a version DEV-11285
- Copper Tape - I used some 1.25" wide copper tape. It is sold as an "anti-slug" barrier at hardware stores. Craft stores have similar products. The tape has an adhesive backing with a protective, peel-off paper. (This type does NOT have conductive adhesive.)
- An Image - Cut from photo, book or magazine
- Decorations - Bangles, baubles, gems or gears
- Insulating Layer - Electrical or duck tape, thin cardboard or plastic, large diameter heat shrink tubing
- Clear tape - To tape the edges of the image to the LCD (or use spray adhesive)
- Gap Filler - Use Sugru or Instamorph or air-dry-clay or hot-glue or even cardboard or plastic to help stabilize the parts
- Adhesives - Depends on what decorations you use, but hey, you have some E6000 right
- Pliers with Snips - Something to bend the wire leads, then snip them flush.
- Soldering Iron - Not absolutely necessary - you can bend and multi-wrap the wires and it will still work, at least for a little while. But I strongly recommend you solder the two electrical connections. It's not that hard and this would make a great introduction to soldering project.
- Scissors - or some way to cut your image to size
Super Advanced Alternative
Since the light-panel uses a standard LED, you can control it from any Arduino style microcontroller. You can make it fade in and out, flash, strobe or blink. You could even add sensors so it reacts to motion, heat, light or sound. My favorite tiny controller boards are the Trinket(3v) and Gemma from Adafruit.
Step 2: Connections
The light-panel is super simple to hook up. There are only two wires to connect for this project.
I strongly recommend that you solder the leads to the board. Wait, don't run away. Soldering is simple and fun - Check out the collection of excellent introductory guides to soldering by Instructables authors.
Positive and Negative
The LED inside the panel has two metal leads, or wires, sticking out of the top.
--- The LONG lead goes to the hole labeled "SW" on the battery holder. This is the positive (+) connection.
--- The SHORT lead goes to the GND hole on the battery holder. This is the negative (-) aka "ground" connection.
For this project I flipped the battery holder over so its smooth face was on the same side as the smooth, bright side of the panel. The switch and battery are then hidden on the back side of the necklace. If you arrange the parts differently, just make sure you hook them up correctly. You won't blow up the light if you hook them up backwards, but LEDs only work when hooked up correctly. Test as you go and make sure the LED lights up before you start soldering.
Do not bend the leads too many times. They are durable, but they will eventually break if you keep bending them back and forth.
Solder, Clip and Go
When you have the parts arranged and the connections correct, solder the two leads and clip the leads flush with the face of the board. If you want to, dab some clear nail polish on the remaining leads, connections and exposed metal parts.
Step 3: Add the Image
You can use anything as the "image" to put over the lighted rectangle. A personal photo, a hand drawn picture, a cutting from a book or magazine. It can be a portrait, still-life or an abstract.
It doesn't even have to be an image. I have used buttons, fake gems, real stones and stained glass. I have tried fabric and faux-fur. If it looks good with a light behind it then use it.
For this example project I used an image cut from an old art book. It was faded, and the color rendition probably wasn't very good to begin with. But it looked vintage and it was free.
Cutting and Attaching
Use the LCD panel as a pattern and cut the image to match. You can use the lighted panel to preview the image and make it easier to get the composition you want.
I cut the image a little oversized so I could wrap the edges around and tape them to the back side of the panel. If you use spray adhesive or two-sided tape on the front, you can cut the image to exactly match the shape of the back-light panel and apply the adhesive to the front of the panel.
Step 4: Stabilize and Shape
Mind the Gap
In this configuration there is a gap between the backlight-panel and the battery-holder. The leads are fairly sturdy, and if you wanted to, you could probably start decorating around them without adding a stabilizer. But I like to add something to form a smoother shape for the body and to insulate the electrical connections.
There was some out-of-date Sugru sitting around the shop, so I used it for this project. I also like to use InstaMorph, but epoxy putty or silicon caulking or air-dry clay or even hot glue can work. Or wrap some cardboard or plastic around the electronics before you add the decorative shell.
Since I am using metallic tape in this version, I wanted to be extra sure to insulate the electronics from the copper surface of the tape. (Bonus Tip - a little clear nail polish dabbed onto the metal parts of the battery holder provide an extra layer of insulation.)
For this project I keep the pendant fairly flat and thin. But you can bulk it up if you want a more substantial look and feel. I simply smoothed some Sugru over the faces of the board and into the gap between the board and light-panel.
*** Leave easy access to the on/off switch.
*** Be sure you can replace the battery easily, but keep it out of sight when the necklace is being worn.
*** Provide a way to attach the pendant to the wire or string for the necklace. I use the holes in the battery board.
Preview your Baubles
This is also a good time to pre-plan where you are going to put your embellishments. You can create visual interest with recesses or standoffs for your baubles. If you are like me, this will be the hardest yet most fun part of the project --- deciding between the hundreds of possible combinations
Step 5: Decorative Shell
I used copper tape to create the decorative shell for this project. The type I used is actually "Anti-Slug" tape from a hardware store. Similar, and usually more expensive versions, are available from crafts suppliers in the stained glass and home décor sections.
The tape is 1.25 inches wide and has a peel-off adhesive backing. (Just in case you are an electronics geek - do not use tape with a conductive adhesive).
This tape fit perfectly on this light-panel, wrapping just a little bit onto the front and completely covering the back. But you can always layer the tape or cut it down to size if you have a different width.
Any thin metal foil will work. Duck tape is super popular right now. I have seen incredible things created with masking tape and paint. Fabric and faux-fur work well. Or weave some paracord or plastic craft cords around the light-panel.
Step 6: Embellishments
Add your beads and baubles and gems. I used some trustworthy E6000 glue to attach some embellishments to various parts of the necklace. You can also use embellishments to modify the image.
Finish and Enjoy
Add some clear coating if you want to. Find a wire or string or cord and hang the pendant at the correct spot for your body.
Now turn it on and enjoy the attention it gets as the lights fade and your necklace glows.