LED Bangle Using CD4049

Here's a small bangle with 6 LEDs which pulse in an interesting pattern. The circuit uses a single CD4049 hex inverter.

List of items required:

• Red LEDs x 3
• Green LEDs x 3
• Cardboard tube x 1
• IC CD4049 x 1
• 220 Ohm resistor x 1
• 1M Ohm resistors x 3
• 0.1uF capacitors x 3
• Wire
• Tools (soldering iron, solder wire, pliers, cutters, knife, etc.)

Cut the cardboard tube to the desired size and make holes for the LEDs as seen in the main image.

I cut the cardboard using a serrated knife. You can smoothen the cardboard edges with sandpaper. For inserting the LEDs, A 50W soldering iron was used to burn holes in the cardboard.

Wire the LEDs as seen in the above image. Make sure you keep the wire lengths sufficient so that the LEDs can reach the holes.

The numbers indicate the connections to the CD4049 pins. See the schematic in the next step.

Wire the schematic as seen in the image. I used a dead bug style to solder the components without any PCB. Does look a bit shabby, but who cares :-P Lets just call it a prototype :-D

Once the schematic is wired up you can power it on using 2 CR2032 batteries connected in series (total 6V). It should work with a single 3V battery too.

If everything was done properly, you should have a nice LED bangle :)

I used the following links as a reference:

http://electronicdesign.com/lighting/low-cost-led-sequencer
http://electronicdesign.com/site-files/electronicdesign.com/files/archive/electronicdesign.com/files/29/6381/figure_01.gif