Introduction: BraceLED - Make a Light Emitting Bracelet Wits LED's

About: I'm a teacher (physics, grades 7 to 10), Maker and product designer. (Check out www.slimme-handen.nl full of experiments, projects for Maker Education and kits for Bibberbeests!). Besides that, I write childre…

I worked hard to make the first BraceLED a cool project and a good Instructable... I really did! ...and yet, a few days after publishing, I got uncomfortable. Restless. Not finished. Although I had plenty of other things to do, I couldn't get my mind off the BraceLED. It seemed to me that I had left something out that should be in.

So after some more tinkering, I proudly present the BraceLED version 2.0. After trying this version out with kids (first my own, later students at school), I decided to make and sell BraceLED kits. Check them out at my webshop if you like.




BraceLED 1.0 has a few (non-critical) problems, that are more or less fixed in this version:

- The LED's are more securely connected to the circuit.

- The layout and design of v2.0 is much more straightforward

- Because of that, BraceLED 2.0 is (even more) easier to make

- In version 1.0, switching on the led's is a bit awkward, using a loose supermagnet. It serves it's purpose, but elegance is a different thing. Version 2.0 solves this handsomely.


I will keep BraceLED 1.0 online, because it has it specific charms that are different or altered in this new version (I like the gap underneath the leds in v1.0, for instance). Perhaps the best of the two versions can be combined in something new... If you have any ideas on that, please step forward!

Step 1: Stuff You Need

Stuff you need:
  • Ducttape in a color of your choice
  • Double sided tape
  • 6-10 LEDs (5 mm). Pick your color
  • Copper foil or aluminium foil, 25 x 10 cm (10" x 4")
  • 1 Button shaped battery. Bigger is better (in this particular case), so pick a model like 2032 or 2450
  • 1 Super (neodymium) disc magnet. 20 mm diameter, 2 mm thick. Europeans: shop at www.supermagnete.de

Total costs: €8,- / US$ 10,- maximum when you use aluminium foil. Copperfoil is expensive.
I got the copperfoil a loooooooooong time ago at a metal-supplier in Rotterdam, NL. The foil is available in various thicknesses. Mine is 0.1 mm, I believe.

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UPDATE Oct 20th '10: Until yesterday, I was unaware of the existence of adhesive conducting foil. It is solderable, and even the adhesive layer is conductive! Now, that sounds GREAT for making a BraceLED!
3M makes it, and so does Laird. The stuff is horribly expensive, though. Farnell dares to ask €40,-/US$50,- for a roll of 16 meters...
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Tools you need:
  • Cellotape (not critical, small strips of ducttape will do as well)
  • Hobby knife
  • Scissors
  • Needle nose pliers
  • Strip of paper to take the measure of a wrist
  • Blunt stick / the backside of a pen

Step 2: Prepare & Setup

To start with, have a look at the exploded view I made of the BraceLED. The making of the BraceLED's different layers is described in steps 2 through 5, starting this step with the two strips of ducttape (I apologize for the crazy background color. I opened the picture in Photoshop to correct a mistake, and then I bumped into the "egalise" function... I'm sort of easily distracted, sometimes.) 

Setup this project by measuring the wrist that's going to wear the BraceLED. See the version 1.0 how to do that.
  • Cut a band of ducttape twice that size and put it _upside down_  / sticky side up onto a worksheet.
  • Fix one end of the ducttape to the worksheet with ordinary sticky tape.
  • Attach another piece of sticky tape to the other end of the ducttape, pull it tightly against the worksheet.
  • Finally, take a band of ducttape a bit longer than the one that is already on the sheet, and stick it neatly over the ducttape on the worksheet. _Sticky side down_! It's almost impossible to make adjustments once the two bands touch each other. The best way I found to get this done is by fixing the tape from the left to the right, carefully holding up the right side of the tape. 

Step 3: Layout the Circuit & Put the LED's Into Place

Making the electrical circuit consists of six actions:

  • Cut two strips of doublesided tape. The sticky strips should be 5 cm (2") longer than the size of the wrist, and about 1,5 cm (0.6") in width.


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Tip!

Cutting the doublesided tape is very, very awkward, because the tape sticks to the scissors while cutting it. I got so fed up with that, I eventually put two strips of doublesided adhesive on top of each other, just like the ducttape band. This way, it was easy to cut a piece of doublesided tape, having both sides protected with the funny slippery paper (the paper that miraculously _won't stick_ to the tape!!!)
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  • Paste the strips of doublesided tape onto the ducttape. Make them stick out about 2.5 cm (1"). See the pictures for the layout.
  • Cut two strips of copper foil with a width of about 0,5 cm (0.2"), with the same length as the doublesided tape strips.
  • Stick the narrow copper (alu) strips on to the double sided tape, across the length axis.
  • Prepare the LED's: To make them stand up more easily, bend the tips in a straight corner, using a plier.
  • Distribute the LED's evenly across the length that the copper strips have in common. Mind the polarity of the LED's! In the picture, all the LED's are faced up with the negative side (the side that has a small straight edge on the bottom). Push the LED's tips firmly into the doublesided tape to make them stick.

Step 4: Closing the Circuit & Making It Blink!

You are getting close to finishing the BraceLED now. In this step, you will close the circuit with two more pieces of copper sheet and sticking the battery into it's place:

  • Cut out two rectangles of copper (alu) sheet, size 5 cm x wrist size (2" x wrist size).
  • From these rectangles, cut away a strip so that you leave an extruding piece of about 2.5 x 2.5 cm (1" x 1"). See the second picture.
  • Place the pieces of copper sheet over the LED's leads and against the doublesided tape. Consult picture number 4 for the layout. Press the sheet firmly against the LED's leads and the doublesided tape beneath them. Use a blunt stick to do this.
  • Cut out a piece of doublesided tape that is _slightly smaller_ than the plus-side of the battery.
  • Before proceeding, check the polarity of the LED's! Stick the tape underneath the protruding part of the copper (alu) sheet and place the battery on top of it, with the positive side down.
  • You can now easily test your circuit, by connecting the minus-side of the battery with the top piece of copper sheet (I forgot to take a picture of that, I'm so sorry). 

Step 5: Finish Up!

The last step will be the... easiest, for a change! In my eager to finish and show off my BraceLED, I made a horrible mistake, of course! So don't rush, play it cool. You're almost there...
  • Cut off the extruding parts of copper/alu sheet, but beware: You must leave a small strip of sheet of the sheet that is not connected to the battery! See picture number one.
  • Turn over the BraceLED, and bend the protruding strip to the backside.
  • On the backside, fix the copper strip and the supermagnet in the same way as you did with the battery:
  • First cut a piece of doublesided tape (slightly smaller than the magnet, but significantly wider than the copper strip).
  • Fix the copper/alu strip onto the backside of the bracelet using the piece of tape.
  • Press the magnet firmly over the copper strip and onto the doublesided tape.

And that's it! You're done!
Close your BraceLED (and the LED-circuit) by fixing the supermagnet against the battery. Because supermagnets conduct electricity well, the current will flow from the battery through the leds, through the magnet back into the battery. Tadaaaa! Blink time! 
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