The Thinking Cap




Introduction: The Thinking Cap

This tutorial will show you how to build a thinking cap using some LEDs, conductive thread, and your very own constructed pressure sensor! The hat will light up when you put it on.

Materials needed:

5 LEDs, preferably white

5 220 Ohm resistors

1 hat that you can cut into

1 clear christmas ornament

hot glue

sewing kit


conductive thread

copper fabric


Step 1: Step 1: Prep Your LEDs and Resistors

So the first part of the hat to focus on is the actual light. In order to use LEDs, you need a few to get the effect bright enough.

You will need to first cut down the prongs on the resistors and LEDs so that they are easier to sew. You can use needlenose pliers to help bend the prongs into circles. Don't forget which end is positive! I used copper tape to do that.

Step 2: STEP 2: Start Sewing Your Circuit

You will need a battery holder which will help you connect the thread to either end of the battery.

First, connect the battery and then sew two long rows of connected stitches.

Note: there should be a BREAK in one of the rows of stitches.

What does this mean? Sew a few stitches that connect the battery, tie a knot and cut the thread. Then a few cm away, start the row of stitches again. See first photo.

This gap in your circuit is where the pressure sensor you make will be attached. Keep that in mind, but don't worry about it at the moment.

After you have the two lines sewn, start to use more conductive thread to connect the resistor and the leds. The resistor and LED should bridge and connect the two initial lines you sewed. See second photo. It should look like a ladder of LEDs and resistors.

So how do you test this to see if it's working?

Connect a the break in your circuit with a piece of conductive thread or copper fabric. If the lights turn on, then your circuit is working! If not, check all connections and solder all the points of connection to ensure maximum stability.

Step 3: STEP 4: Construct the Pressure Sensor

You will need two small swatches of copper fabric and a little piece of foam.

First, cut out the swatches to evenly match the size of the fabric. Then, cut a hole in the foam. Glue the foam in the middle of the two pieces. NOTE: Only glue the copper pieces to each side of the foam. Make sure the copper fabric is not touching in the middle. This should look like a copper covered ice cream sandwich.

How do you test this?

You can connect alligator clips to a battery holder (battery included) and connect those to an LED in a circuit. Make sure one positive end is clamped onto one piece of the copper fabric in your sensor and the negative end is clamped to the other piece. When you press down, the LED will light up.

Step 4: STEP 5: Construct the Hat

First, take your ornament and see if your circuit fits inside of the ornament. If it does, great! If it doesn't, widen the hole. I had to melt mine, but there are other ways.

Next, take some sandpaper and sand down the outside surface of the ornament until it is frosted looking. This will diffuse the lights from the LEDs.

After that, cut two holes in the top of the hat so your sensor threads can connect to the circuit. I connected two threads to my circuit (one positive, one negative) and then threaded them through the holes in the hat. Please make sure they don't touch! This will short circuit the hat.

Then, glue the LED circuit ball on the top with the threads extending through into the inside of the hat.

After the glue dries, you can glue the pressure sensor onto the inner rim of the hat where the forehead sits. Connect the positive thread from your circuit to one side of the sensor and the negative side to the other using a sewing needle. Secure everything with hot glue!

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    6 years ago

    Useful to wear it while cycling in evening time.