Welcome to my instructable on how to make a battery powered glowing bracelet out of materials gathered from a broken laptop LCD panel. This guide will show you which materials can be gathered from the back-light of a broken LCD panel and how to use them to create a glowing piece of jewelry, in this case a bracelet like the one pictured above.
Step 1: Step 1: Disassemble the LCD Back-light (gathering Materials)
What happens when you a find a laptop in the trash but it is damaged beyond belief? You will not be expecting any computing power from a pile of e-waste but the raw materials left behind are quite interesting. Ones of the most exciting materials are located on the screen panel (if it is not too bent only broken glass and liquid crystal layer). After disassembling the backlight you will be left with a number of plastic sheets, the all serve a purpose in redirecting and difussing the light. Above I show how to take apart a panel backlight and the different sheets that compose it. I will use the bottom thick plastic sheet that is edgelit and the one that is like a fresnel lens.
Step 2: Other Materials
The other materials that compose the bracelet could be salvaged or bought, they are:
- A prototype pcb.
- Two LR44 button cells.
- An ON/OFF switch.
- 4 Leds of any color or shape but flat top leds I think work best.
- 4 12 Ohm resistors 1/8W ( I used 1/4W that I had).
- Scrap metal.
- Salvaged screws.
- Acrylic scraps.
- Thin cable.
- Heatshrink tubing.
Step 3: Tools
- A small rotary tool with cutting disc.
- Soldering Iron.
- Dichloromethane (to fuse acrylic)
- A drill with small drill bits.
- Box cutter.
- Heat gun.
Step 4: Step 4: Building the Cylinder Part 1: Cutting the Plastic
The bottom thick plastic will be the structure of our bracelet. This plastic has small dots engraved on It's surface which direct the light. Measure the thickness of the bracelet you want and trace a line vertically while placing the sheet of plastic in a landscape position. Score it several times and cut almost if not all the way through because if you try to score and bend it like one would do with acrylic it will break uneven.
Step 5: Step 5: Building the Cylinder Part 2: Bending the Plastic.
To bend the sheet to a cylinder I put it over an electric stove in high and held it with my hands inside thick leather gloves, wait for it to get soft and wrap it around a tube or cylinder ( I used an old spray paint can, SOMETHING YOU SHOULD NEVER DO!, I drained all the gas and drilled a hole in the can so it would not explode when i heated it. PLEASE DO NOT DO THIS! I DID IT AND WAS NOT CARELESS BUT IT DOES NOT MEAN IT WAS NOT DANGEROUS!), put the side of the sheet that is not engraved towards the stove. After doing this I noticed that the plastic had a white spot in it's side, so do not leave it unmoved over the stove or this will happen all over. I inspected the shape and saw that it was kind of warped so I put the cylinder over the paint can and used a heat gun to correct the shape.
Step 6: Step 6: Builing the LED Pcb
Now that we have the base structure we can build the circuit for the leds. Cut down the prototyping pcb to slightly less than the width of the bracelet and a height of 4 holes. I used 2.8v blue LEDS and used an online LED calculator to know which resistors to use when 4 are powered with a 3v battery (two LR44 batts). Place the leds and resistors in the order that is shown in the pictures above, then solder the leds and resistors, make the cable connections on the component side of the pcb and join the solder pads that are shown in the next image. To complete the circuit finally add the positive and negative cables.
Step 7: Solder Diagram
Step 8: Step 8: Building the Battery and PCB Holder With an ON/OFF Switch Part 1
This step can be dismissed because it was very time consuming and there is need for special materials like Dichloromethane to glue the acrylic together, but I constructed my own battery and pcb holder because I wanted to be able to change the batteries when they died and that the battery holder would be transparent. There is no right or wrong way to do this and because of the salvaged nature of this project the design can change depending on the materials at hand.
I started by gluing two pieces of acrylic with Dichloromethane which results in a thick acrylic sheet. measured and marked the size of the LR44 batteries and with a rotary tool with a cylindrical burr attached y carved a cylindrical hole in to which the battery can be placed. when satisfied with the first hole make the second one.
I used a thin acrylic rectangle on which I will glue the battery holder and where the PCB will be screwed on to only to finally attach the whole thing to the thick end of our plastic cylinder.
Step 9: Step 9: Building the Battery and PCB Holder With an ON/OFF Switch Part 2
The batteries have to be connected, so to complete the circuit between them I cut a small piece of thin metal sheet that i had laying around and put it between the two battery holes to connect the batteries when one is put positive side down an the other negative side down. Because the negative and positive cables that go to the LED circuit have to be mechanically connected to the battery assemble I created a battery door that is held by two screws: one permanently connected to the piece of acrylic that acts as pivot to hold the door in place when the first screw that is screwed to a standoff is removed to move the door and reveal the batteries behind it. I used the same plastic that was used to make the cylinder because it is kind of bendy. The battery door has two holes aligned with the batteries through which the negative and positive cables go and are connected to two pieces of copper sheet that act as contacts. Finally I created a hole with the shape of a small ON/OFF switch that i salvaged from a junk PCB I had laying around, drilled two holes for the cables to go through and with hot glue adhered the switch to the acrylic. The PCB is held to the underside of the battery holder with two small screws, the LEDS are pinted towards the edge of the cylindrical plastic sheet.
Step 10: Painting the LEDS
I blocked the light coming from the sides and back od the LED with some white model paint so the light going through the plastic is not toned down by the brightness of the leds.
Step 11: Attaching Everything Together
Screw the pcb to the underside of the Battery holder assemble, I decided to put some tape over the solder side of the pcb so it does not touch the skin (I cut it from a plastic tape the broken laptop motherboard had on it).
Step 12: Connecting the Electronics
Connect the positive wire to the switch and then the second wire from the switch to the positive battery contact on the lid, then connect the negative contact cable on the lid to the negative cable on the PCB, trim the wires so they do not hang out too much. Test the circuit before soldering the cables together and remember to slide the shrink tube before.
Step 13: Step 13: Adding the Second Plastic
Cut the fresnel-like plastic sheet the same width and length as the sheet that formed the cylinder.
Drill two holes on each end of the cylinder the size that fits the small screws you will use, as in the rest of the proyect the screws will carve the threads themselves on the plastic, just do not drill the holes too small so that when threading the plastic does not break. Make the same holes on the second sheet of plastic, put the fresnel-sheet the textured side towards the cylinder. Screw the battery assemble on the thick side of the cylinder and make sure the LEDS are facing towards the edge of the plastic and are fairly close to it. Screw the fresnel-sheet to the thin end of the cylinder.
Step 14: TURN THE LIGHTS ON!!!!!
You are finished, turn on your glowing bracelet and go out at night, now everyone will know where you are in the dark and it looks really cool. ;)
Thanks for looking at my first instructable.
Don't forget to vote for me on the bracelet challenge!!!!