You’ll need a smartphone or tablet that supports Bluetooth 4.0 LE in the hardware and operating system. Recent versions of the iPhone and iPad both work, as well as the latest round of Android phones and tablets. Some laptops may work too!
If you’re not sure, it’s easy to test for this: download and try one of the Bluetooth apps mentioned on the “Use It!” page of this guide. Older devices and OS versions (not supporting Bluetooth 4.0 LE) aren’t compatible, and the software will simply refuse to work.
Most top hats are slightly tapered one way or another. It’s unlikely you’ll find one with exactly straight sides, but try to find something as close to straight as possible, so the circumference is fairly uniform (we’ll tweak this later). The cheap paper Pilgrim hats at the party store are much too tapered, don’t use these!
Make sure the sides of the hat are tall enough, 4 inches (10 cm) minimum. You don’t need to go all Lincoln stovepipe unless that’s the look you’re after.
The Bluetooth library and all those NeoPixels require a lot of RAM, and most mainstream ATmega-based boards (Uno, Boarduino, etc.) won’t work. The Arduino Micro’s 32U4 processor has an extra 512 bytes of RAM that turn out to be critical to this project!
Cutting-edge boards like the Arduino Due, Netduino or Teensy 3 are unlikely to work here — though powerful, they’re based on different processors and only “mostly” Arduino compatible. Trinket and Gemma lack enough RAM, and an Arduino Mega is just overkill.
- Three AA alkaline cells (4.5V total) — cheap and easy, this is what we’ll use for ours!
- Four AA NiMH rechargeables (4.8V total)
- A slim lithium-polymer battery (3.7V, 1200 mAh or larger)
Adafruit Bluefruit LE nRF8001 breakout
- 4 meters (1 reel) of 60 NeoPixel LED strip
- Snap-Action 5-Wire Block Connector (pack of 3)