The Raspberry Pi is a credit card-sized computer. The Raspberry Pi Model A+ is a smaller, low-cost version of the Raspberry Pi. It is based on the BCM2835 system-on-chip (SoC), which includes an ARM11 processor and a powerful GPU. The Raspberry Pi Model A+ is recommended more for embedded and low-power projects that do not require Ethernet or multiple USB ports.
The Raspberry Pi was designed by the Raspberry Pi Foundation in order to provide an affordable platform for experimentation and education in computer programming. The Raspberry Pi can be used for many of the things that a normal PC does, including using high-level computer programming languages (like Python), acting as a USB host, and operating system multitasking. Over five million Raspberry Pis have been sold, and lots of resources for the Raspberry Pi are available online.
With its 0.1″-spaced GPIO header and small size, the Raspberry Pi also works as a programmable controller in a wide variety of robotics and electronics applications.