The Raspberry Pi is a series of credit card-sized single-board low cost computers developed by the Raspberry Pi Foundation to promote the teaching of basic computer science in schools and developing countries. These little computers rely on an SD card for booting and long-term storage. They can drive an HDMI monitor for programming which is typically done in Python. Many of these board run headless (no monitor) inside of small electronics projects like hobbiest robots, etc.
The original Raspberry Pi and Raspberry Pi 2 are manufactured in several board configurations through licensed manufacturing agreements with Newark Element 14. The firmware is closed-source.
Raspberry Pi boards are priced as low as $20 but typically run around $35 USD. A smaller version called the Pi Zero with limited input/output (I/O), general-purpose input/output (GPIO), abilities released in November 2015 for $5.00.
You can purchase Raspi boards from companies like Adafruit and SparkFun Electronics. Then bring your board to Tinkersmiths Makerspace weekly Monday night ElectroFunk Workshop for some programming fun goodness.
Electronic Raspberry Pi Front
Electronic Raspberry Pi Charlottesville
All models feature a Broadcom system on a chip (SoC), which includes an ARM compatible central processing unit (CPU) and an on chip graphics processing unit (GPU, a VideoCore IV). CPU speed ranges from 700 MHz to 1.2 GHz for the Pi 3 and on board memory range from 256 MB to 1 GB RAM. Secure Digital SD cards are used to store the operating system and program memory in either the SDHC or MicroSDHC sizes. Most boards have between one and four USB slots, HDMI and composite video output, and a 3.5 mm phono jack for audio. Lower level output is provided by a number of GPIO pins which support common protocols like I²C. Some models have an 8P8C Ethernet port and the Pi 3 has on board Wi-Fi 802.11n and Bluetooth.
In February 2016, the Raspberry Pi Foundation announced that they had sold eight million devices.