I recently learned how to code using an Arduino Uno, and I had this great idea for a helmet prop, with eyes that follow where the head is looking. So I dug around and found an accelerometer and a grid of color changing pixels, and started drawing up plans. what resulted was a sinister, yet goofy looking pyramid helmet. Here is how you make one for yourself!

Supplies

one (1) Arduino Uno and USB cord
one (1) L3G4200 triple axis gyro (available at MPJA.com, or anywhere these types of modules can be sold)
one (1) Adafruit 16x32 neopixel grid
one (1) Adafruit Arduino shield for the 16x32 neopixel grid AND stackable connectors(sold separately)
one (1) 9 volt battery or a small cellphone battery booster (check the MAH on your battery, the higher that number, the longer your battery will last)
Soldering equipment (Soldering pen, sponge, and solder)
two to three (2-3) Large sheets of black poster board (the cardboard-y kind. you are constructing the helmet out of the stuff, so pick something that feels sturdy)
glue, Elmers is fine since we are using plaster board
velcro strips
x-acto or box cutter knife
any and all appropriate resistors and wires for wiring an Arduino and a red LED (You can normally get these in a large bundle in a bunch of colors (I recommend MPJA.com to find these, you can normally get a good deal on shipping)
guts and determination. (Do NOT skip this item, it makes finishing very hard)
if you wanted to decorate it in any way, go ahead and get stickers or paint, go nuts!

Step 1: Soldering and Attaching the RGB Shield to Your Arduino

Ok so this might be the most daunting step because it requires some soldering experience. What you are going to want to do is solder enough headers in order to be able to stack this baby onto the Arduino and plug all of the headers into. My advice here is to have patience. Once you finish, you should be able to simple plug the shield into the top of the Arduino. You also need to solder the connector to the RGB grid. This will make installing the RGB grid way easier in the long run and will prevent your Arduino from looking like a plate of technicolored spaghetti.

Step 2: Wiring Your Arduino

Speaking of spaghetti, lets look at your noodles. If you like, I have already made a tutorial on how to wire the Accelerometer to the Arduino.

https://www.instructables.com/id/Accelerometer-Sen...

in brief, you want to attach the GND to ground, the VCC and SDO to the 3.3v. to do this, i soldered together a "Y" shaped red wire and plugged them both into the 3.3v Arduino port. then attach the SDA to the A4 port, and the SCL to the A5 port.

Next the install the red LED on top, you need to plug in the positive wire to the '12' port, and the negative to a ground. i soldered an appropriate sized resistor to the positive wire and covered in plastic for a more seamless wiring (no breadboard required). then just place the LED to the other end.

Now just plug in the 12 pin wire from the RGB screen to the Arduino shield.

Thats all the wiring.

Step 3: Coding Your Arduino

ok here is where some personality can start to shine, and it has been made easy thanks to the folks at Adafruit. attached below is the code that I used for mine. It's cobbled together using code from several sources, as well as my own. If you wanted to make it exactly how I did mine, all you would have to do is upload the code to your Arduino and, if everything was wired correctly, you should be good to go. However, you should look at some of the example libraries by Adafruit and look into how the LED grid can be programmed. You might find something you like and can make something special for yourself. I have made it easy to do minor tweaks to the code (The Eye colors can be changed by changing 3 variables near the top of the code). I have also done the liberty to labeling the code for easier navigation.

https://drive.google.com/file/d/1k664hEfakLb8LQjPowzk9ua5LGTmhq68/view?usp=sharing

Step 4: Building the Main Frame of the Pyramid Helmet

Now that the electronics have been sorted for the time being, let's get to the construction of the helmet. I hope everyone paid attention in geometry class. anyone? no? ok good neither did I.

You need to make four triangles that meet to form a pyramid shape that fully covered the top half of your face and them some. For me, this meant making my triangles 18" long and 15" tall if measured perpendicularly (see image for details) cut a reference triangle using a piece of cardboard you don't care about (an old box will do). You need to also have a small flap on one side of each triangle to give you some surface area to glue the triangles together. Then trace four of these triangles onto your poster boards, try to use as little surface area as possible, you have other things to cut. after this but this takes up the most board. cut out these triangles. Once you do that, gently cut through the flap on the one side of the triangle, but not all the way through it, so that it acts like a hinge. Now glue the flap to the underside of the other triangles until you form the pyramid. If you finish gluing and it looks like a pyramid, CONGRATS, you finished this step. let it dry before proceeding.

Step 5: Building the Grid Holder

This is the part of the Frame that holds the RGB grid, building this is really simple, but you have to do it right. You want to cut what is basically a triangle. a quick way to do this is to use the triangle template you used to build the main frame, fold it in half, and trace out a shape that is a 1/2 inch longer than the height of the frame, and the bottom of which is wide enough the fit the frame with some room to spare. make sure to also cut a tab on the angled part of this triangle so that you can attach it to the front.

Cut two rectangles, one the width of the bottom of the angled piece, and one the width of the top. glue it all together, or use a strong tape on the inside.

once that all is sorted, cut two slits into the front face of the pyramid. then use the two tabs you cut to attach the frame to the pyramid.

take two small rectangles and glue them to the inside of this box in such a way that the grid sits flush with the frame.

Step 6: Building the Head Attachment and Arduino Base

You need to measure you head for this step. an easy way to do this is take a piece of string and wrap it around your head, then measure the string with a ruler.

Next measure out a rectangle of poster board (around 4 inches wide) that is the length of your head. Score the rectangle several times widthwise so that you can "fold" it into a circle. Make sure that this fits snugly on your head, then glue it together.

cut a 8"x8" square, cut off the corners to allow the wires some room to sneak up. glue your head shape to the underside of this "square".

cut two small flaps and score them so that they can bend, attach one side of the velcro to either one, and the opposite side to the inside of the pyramid. this will hold the head case and Arduino in place to the pyramid, and allow you to take it off if something is wrong with the electronics

The Arduino rests on top of the "square" with the accelerometer facing the front of the helmet.

Step 7: Placing the Arduino, LED, and Grid Into the Helmet (Home Stretch!)

in order to make sure the Arduino sits still, I built a small case for the Arduino and accelerometer. If you do not have access to a 3D printer, Just make sure the accelerometer is secure and facing the front of the helmet in order to work properly. I then used sticky tac to hold the electronics in place.

Next take the LED light and attach it to the tip of the pyramid. I also built a 3D model for this, although this is unnecessary. I have put the 3D models in the Google Drive that I linked to earlier. Now attach the battery pack to the Arduino, and put all the velcro back on.