Introduction: LED Pin

This project is to build a Wonder Woman themed pin containing LED lights. The design is based off the logo shown here.

Step 1: You Will Need...

Two pieces of felt, one red and one yellow.

Two LED lights, one red and one yellow.

Two resistors, both 100 Ohms.

One 3 volt battery pack.

Conductive thread.

Sewing needles.

Basic sewing supplies such as a safety pin, scissors, cotton thread and fabric glue.

Step 2: Design Your Circuit

I wanted to connect the LED lights in parallel so they would both draw the same current from the battery. I also needed to determine what size resistor to use based on the LEDs I'm using.

The LED specifications for red LEDs are avalaibe on the data sheet, located at:


This gave me the diode forward voltage of 1.85, and the diode forward current of 20mA.

I then used the LED resistance calculator to design my circuit. This is located at:


Step 3: Final Circuit Design

Using a 3 volt battery and 2 LEDs, this is the final circuit.

Note that the design calls for 68 ohm resistors, which I did not have. I substituted 100 ohm resistors.

Step 4: Cut the Base Piece

Cut out a circle about 2 and 1/2 inches in diamater of red felt. This is the base of the piece.

On the back, draw guidelines for where the LEDs, resistors, wires, and battery will go. I found it useful to draw this on paper first, then transfer that to the felt.

Step 5: Attach Components to Felt

Punch holes in the felt for the LEDs.

Attach the battery pack to the felt with conductive thread. Run the thread from the positive end of the pack, around the edge of the felt, to the positive prong on the top LED.

Attach a resistor to the negative prong of the top LED, then run thread from it to the negative end of the pack.

Repeat for second LED by running a length of conductive tread from the positive power thread to the on the side of the felt to the positive prong of the lower LED. Then add another resistor and connect it to the negative thread.

Step 6: Clean Up

Trim excess thread and prongs from LEDs.

On the other side of the felt, add the "W" logo cut from the yellow felt. Use fabric glue to attach logo. Add black detailing with a marker if you'd like.

Step 7: Add Pin

To complete the project sew a small tab of felt to the top with a safety pin to attach to clothing. Pin will light up when a 3 volt battery is inserted into the pack.



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That's a cute pin :)