To follow this guide you'll need a Raspberry Pi. Either the original model (like a Raspberry Pi B+, B, A+, or A) or the faster Raspberry Pi 2 will work, however I highly recommend using the Raspberry Pi 2. The Pi 2 has more memory, runs a little faster than the original Pi and has multiple CPU cores so it can do other things while running a Processing sketch. However even the Pi 2 is still a somewhat slow computer compared to modern desktops & laptops--complex Processing sketches won't work well on the Pi!
You can also use a PiTFT display to show a Processing sketch. Any of the PiTFT displays will work and you can find them in sizes from 2.2 inches up to 3.5 inches.
If you need a bigger display you can use the Pi Foundation's 7" TFT display, a HDMI display or DPI display (using the DPI TFT kippah), or just plug in a computer or television to the Pi's HDMI output.
If you'd like to control hardware GPIO pins on the Pi from Processing you might want a Pi Cobbler GPIO breakout cable and a few switches, LEDs, and resistors to experiment with. All of these parts are available in this handy Raspberry Pi 2 starter kit (which you can also get without the Pi 2 if you already have one).
To use Processing on the Pi you'll want to use the latest Raspbian operating system. Currently there are two version of Raspbian, an older version called Wheezy (based on Debian Wheezy) and the latest version called Jessie (based on Debian Jessie). I recommend using the newest Jessie release, but you can still use the older Wheezy release if necessary. Grab the official Raspbian release from this page and burn it to a SD card and install on the Pi.
If you're using a PiTFT be sure to instead follow the directions on the appropriate PiTFT guide to assemble and setup the Pi. I highly recommend using the easy install image from the guide to get started easily:
- PiTFT 3.5" Guide
- PiTFT 3.2" Guide
- PiTFT 2.8" Capacitive Touch Guide
- PiTFT 2.8" Resistive Touch Guide
- PiTFT 2.4" Guide
- PiTFT 2.2" Guide
You'll also want to make sure your Pi has access to the internet from either a wired or wireless networking adapter. See this guide on setting up wired and wireless networking on a Raspberry Pi if you need help.
Once your Pi is setup and connected to the internet then continue on to learn how to install Processing on the Pi.