Reddit mentions of PJRC Teensy 3.2

Replace the Arduino with a Teensy3.2; it runs Arduino code and is very small in comparison (with more RAM than the Arduino Uno). Solder the connections to the Teensy. Power the Teensy directly from the battery bank and use a micro USB breakout to convert the battery bank's output to wires that can be soldered into the Teensy. The LEDs should receive power in parallel, not in series. I've found the capacitor unnecessary in every wearable LED project I've done. If you only have single-core wire, helix the three strands together to make a neater cable. I usually build a holster from a coat hanger to hold the battery pack on the hat. It can also go in your pocket.

Hey there everyone! Sorry for the late followup. I've been unpacking from graduation and the like... Also, as a neat update to my earlier post, I was just contacted by the College Football Hall of Fame to display my cap in the Hall for a few weeks. Neat!

Unfortunately, I didn't take pictures during the build process, but here's my general construction setup.

Supplies needed:

• [12,000 mAh portable battery pack on Amazon (might be overkill)]
  (https://www.amazon.com/gp/product/B00SSY1AJU/ref=oh_aui_detailpage_o00_s01?ie=UTF8&psc=1)
  
  
• Teensy 3.2 microcontroller running Arduino firmware
  
  
• 32x32 LED matrix with 6mm pitch
  
  
• [SmartMatrix SD Shield v3 - for Teensy 3.2]
  (https://www.adafruit.com/product/1902)
  
  
• Solder/Soldering iron
  
• Boxcutter
  
• LOTS of hot glue
  
• Male USB-male barrel jack cable (or a means to create one. Just requires cutting and soldering two wires together)
  
• MicroSD cards (Formatted in FAT32)
  
  Steps:
  
  

1. The first step is to assemble your SmartMatrix SD Shield, as described in the tutorial here. This attachment will allow you to easily connect your Teensy 3.2 microcontroller to your 32x32 matrix, as well as display animated GIFs off of an SD card. Follow all of the steps, and make sure to cut the connections on the board where the guide indicates.
   
   
2. Download the Arduino IDE here.
   
   
3. Install the Teensy Loader Application for your Arduino IDE here.
   
   
4. Connect your Teensy 3.2 to your Arduino IDE.
   
   
5. You will need to install the SmartMatrix Library for Arduino, located here. If you need information about correctly installing Arduino libraries, go here.
   
   
6. I based my project off of the SmartMatrix Library's AnimatedGIFs example, located in File, Examples, SmartMatrix_32x32, AnimatedGIFs. The guide located here may also be useful. Documentation on scrolling text is also located on the SmartMatrix Github.
   
   
7. The 32x32 LED display will not lay perfectly flat on a mortarboard with the SmartMatrix SD Shield and Teensy 3.2 attached. You will need to do some cutting from the top of the mortarboard and assembly with hot glue to make it stay. I mounted the LED display to the mortarboard with the display's included four mounting screws that attach to the back of the display.
   
   
8. Plug in your USB battery to the barrel jack on the SmartMatrix SD shield, and verify that the Arduino is powered and the display is operational
   
   
9. Success!
   
   General Information
   
   

• YES I realize I mounted the display a little crooked, and it bothers me as much as it does you... Cut me some slack though, it was 2AM the night before graduation and I'd already hacked half the cardboard in my mortarboard to shreds :P
  
  
• The 32x32 LED matrix typically draws around 2A, ~4A MAX when all LEDs are white and at full intensity. The 2A from the USB battery should do the trick though, and will likely last for around 4-5 hours.
  
  
• Total build cost was around $70-80
  
  
• Total time to build was roughly ten hours.
  
  
• In order to display animated GIFs correctly, they will need to be formatted as 32x32 .gif files on the SD card. Sizing, as well as where to put the GIFs is covered in the guide in Step 6.
  
  Picture of the Grad Cap During Graduation
  
  
• http://i.imgur.com/tEyHURP.jpg
  
  Link to Source Video
  
  
• https://www.youtube.com/watch?v=A-VXwk23DyI&
  
  Arduino Source Code
  
  
• http://pastebin.com/yBsZisqG

You can see the patterns in judgement on the graph in u/pieman445's comment. There's gaps where you simply can't hit the arrow. It could lead to lost steps or late judgements even though you stepped on time. I switched over to a teensy microcontroller and it completely eliminated the problem

Cool, I have been messing with some stuff I have at home already, I am going to go with a Tennsy setup for this. The Teensy 3.2 is small and plenty powerful enough.
https://www.amazon.com/PJRC-6485230-Teensy-3-2/dp/B015M3K5NG/ref=sr_1_1?ie=UTF8&qid=1510164964&sr=8-1&keywords=teensy+3.2

it has an add on board that handles everything else called a "prop board" for doing projects exactly like this. 10DOF motion, 2W amp, controls LEDs also.
https://www.amazon.com/gp/product/B06ZYN7LLC/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1

price is still cheaper than a sound board, and way more configurable.