Here is how you can make your own Magical LED Hat.

Step 1: Get a Hat!

This felt top hat hat is cheap and has a lot of room to put everything in it. I bought two just in case. I have to say though considering how much use the hat has had it is holding up well. I found my hats on Amazon.

Step 2: What You Will Need

For this project I Used:
(1) Felt Top Hat
(1) LED Magician (or your an Arduino or your own LED controller)
(72) 3mm, 3v, 20mA LEDs - assorted colors
(12) 47-ohm 1/4watt resistors (I did not have 1/2 watt on hand so I doubled up)
(2) 2xAA Battery Holders
(1) Slide Switch
(1) male/female Deans plug (I did this so i can re-use the LED magician in other projects)

Blue Painters Tape
Several Feet of 1/4-inch wide Copper Tape
Solder

Step 3: Measure Twice, Cut Once

I am using the LED Magician as my LED Controller, I can have up to 12 rows of LEDs. That meant I had to divide the hat into 12 equal sections. You will need to divide your hat into as many sections as you decide to light. I wanted the LEDs to line up very nicely so I used blue painters tape to draw out my lines.

Take a strip of paper, wrap it around the hat and marked where it meets. then lay the paper flat on your workbench and make your measurements. Wrap the paper back around the hat and transfer the marks to the blue painters tape.

I taped the top as I originally thought I would put LEDs on top too.

Step 4: Make Your Mark

You can see here the lines that I transferred. The dots represent where the LEDs will go. Again, I measured and laid them in a pattern that I liked. The LED Magician can handle a lot of LEDs. I could, if I had the power put up to 100 LEDs in each row, but that would be crazy for a hat. (or would it? I still have a second hat..hmmmm). FOr my hat I decided to go with 3mm, 3v, clear LEDs in 12 rows of 6. You could go with larger or smaller LEDs. Adjust accordingly.

Step 5: The Scary Part - Make Some Holes

Each LED leg has to go through the hat and you need to make a hole for each leg of the LED. Even though you might think this is a "cheap" hat, the felt is very strong. I tried pushing the LEDs through. No luck, the legs bent. I found if I used a small finish nail or a small awl I could make the hole. I also labeled everything so I would not make a mistake later. I decided I wanted each row to be its own color and I wrote it right on the tape so that I could be sure I did not end up with two of the same color next to each other.

You will also need to pay attention to the legs of the LEDs, one is longer - that is the (+) side, or anode. The shorter side is the (-) cathode side. You want to be sure that you push them through the same way every time. To ensure that I did not make a mistake I only did one row at a time.

Step 6: A Little About the Circuit

THE LED Magician made it very easy to build and control the LED circuits. All I needed to do was connect the 6v (4xAA) battery to the LED MAgician, connect a common negative (-) and then the (+) from each of the 12 circuits.

You will need to do a little math to figure out your LED arrangement. LEDs are sensitive to to much electric current, so we use resistors to limit the current flowing through them. Considering that I decided to add 72 LEDs to a hat, I did not want to have 72 LEDs and 72 resistors. I decided that it would be more efficient to wire the resistors in parallel. In other words the LEDs would all share a (+) positive electrical connection and a (-) negative electrical connection with one resistor.

Not being the math whiz I once was, I searched the web for an LED calculator for a Parallel circuit and I found exactly that.

There is also several Instructables on the topic. Here is one: https://www.instructables.com/id/LEDs-for-Beginners/step8/Wiring-up-multiple-LEDs-in-parallel/

Step 7: Be Prepared

Working inside the hat can be tough if you have big hands like mine. Soldering inside the hat is not impossible but you need to pay attention. If you hold the heat to long you will start to smell burning felt. The copper tape transfers heat very well. At first I was doing all the soldering in the hat, then I realized it was better to prep all the copper strips first and minimize the soldering to in the hat.

You will need a a (+) positive and (-) negative copper strip for each row of LEDs. The resistor(s) is soldered on the (-) negative strip and the wire lead for the LED Magician goes on the positive lead. Each lead was bout six inches long.

If you have never soldered before, practice with some scraps. If you are really worried about soldering find a local Maker Space and go visit them during their open days such as " Soldering Sunday."

If you are in New Jersey or New York you can come visit the space I belong to - FUBAR Labs. Every Sunday at 1:30 is Soldering Sunday and you are welcome to come.

Step 8: Get in the Hat

On the inside of the hat run a copper strip around the top. This will be come you (-) negative for all the LEDs. The Resistor is soldered to this copper ring from each (-) negative lead.

Start with one row and push the LEDs through the hat. Do only one row at a time so you can check your work.
After the LEDS are all through, double check that you have the (+) long leg and the (-) leg all on the same side.

Add the copper strips you prepped. Again, resistor goes on the negative, short, side of the LEDs. Holding the LED firmly on the out side bend the legs apart. The LED should be firmly secure in place. Now you are ready to solder the LED legs to the copper tape.

Work fast with a hot iron. No need to be a perfectionist, you just need a good joint here that will conduct and hold the LED in place.

Step 9: RInse and Repeat

72 LEDs is a lot of LEDs when you are soldering them one at a time. It will be worth it . Just take your time and label everything. I taped loose wires out of my way so they did not fall on the hot iron as I worked through each row.

As you add rows remove the tape on the outside. I found that if i was careful with a sharp hobby knife I could get the tape cleanly away without leaving little bits to clean up.

Step 10: Pull a Magician Out of the Hat

I wanted to reuse my controller and did not want to have it permanently in the hat. I cut a piece of black foam board and used hot glue to mount the AA Battery holders and the LED Magician. The foam board also made it easy to add an on/off switch and hide all the wires. You may notice I used some Deans plugs between the batteries and the LED Magician, these were recycled from an old RC airplane. I added the connectors in case I wanted to change the type of battery I use in the future.

The LED MAgician is made by a Maker in Singapore. I have fallen in love with this little device. It is so easy to use, no programming, no complicated setup. Just connect your LEDs and use the 8 buttons to cycle through 32 modes, speed, etc. LED Magician Specs

The hat has enough room that if you have another way to control the LEDs, such as an Arduino, then go for it. Its your hat!

Step 11: Wear Your Hat Proudly!

TA DA! or should I say ABRA-CA-DA-BRA! Your Magical LED hat is ready!

We have had a lot of fun with this hat. Like I said my son wore it at Geek Create and everyone was loving the hat and taking pictures with him.

Go make some MAGIC!