Portable LED Flashlight

After doing a bit of research and watching a series of instructable videos, I got to sketching a possible option for a portable flashlight:

I wanted to create a half cylinder ring with a flat backing that houses a 3V battery. It has a keyhole motif I can stick the legs of a small LED through and mold the cathode/anode wires against the interior of the cylinder. The cathode is hot glued to the ground of a coin battery while the anode is fed through the base so when the ring is worn on one finger, the user can subtly turn on the light by applying pressure on the anode against the battery with another finger, thus completing a circuit. I made a quick mock-up using hot glue and cardboard. It worked, so I began thinking about materials. I thought it might be an interesting juxtaposition to use an aluminum half-cylinder and wooden base. I scavenged through the junk shelf to cobble together my BOM:

Wood (base)

Aluminum pipe (cylindrical segment)

Small screws (to attach cylindrical segment to wooden base)


3V Coin battery

Tools used:

Pipe cutter – cut to ring height

Dremel – cut pipe in half

Drill – drill holes in cylindrical segment for LED and battery

Drill Press – drill holes in cylindrical segment for LED and battery

Long story short, after the third prototype, I came to terms that I made too many compromises along the way due to lack of experience with materials and tools in the shop. Although the electronics side worked, they failed in aesthetic appeal.




I moved on. By then, I didn’t have a lot of time left for experimentation and marched back to the junk shelf for more inspiration. I couldn’t find anything I liked so I rummaged through the soft lab area and found a pair of earrings in a box containing small knick-knacks like beads and grommets.

Materials used:


3V Battery

LED fairy lights


Soldering iron

Wire cutters


Hot glue gun


First thing I did was test which wires are anode/cathode in the LED fairy lights. After I burned off the protective coating on the wire ends, I soldered extension wires to them for better reliability. I tested three soldering irons before actually getting somewhere because the tips were oxidized. I hot glued the cathode to ground and began decoratively wrapping the fairy lights around the hoop and creating a nest for the coin battery. One wire is wrapped to maintain a separation between the anode and the coin battery so it does not light up unless pressed down.


I think it’s successful in that it is portable in a less obvious way.

One thought on “Portable LED Flashlight

  1. Nice work. I love that you made so many prototypes. I’d also like to see a final image with all of the flashlights you made (cardboard, pipe, pipe coupler, and earrings).

    An image of you (or someone) wearing the earrings and lighting them would make for great documentation.

    Glad you tried so many different tools and techniques.

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