The Raspberry Pi is a credit-card-sized computer created by the non-profit Raspberry Pi Foundation in the UK. It all started when a chap named Eben Upton (now an employee at Broadcom) got together with his colleagues at the University of Cambridge's computer laboratory, to discuss how they could bring back the kind of simple programming and experimentation that was widespread among kids in the 1980s on home computers such as the BBC Micro, ZX Spectrum, and Commodore 64.

After several years of tinkering, the Foundation came up with two designs for the Raspberry Pi. The $35 Model B was released first, around February 2012, originally with 256 MB of RAM. A second revision, with 512 MB of RAM, was announced in October 2012 and the $25 Model A went on sale the following year, in February 2013.

In July 2014, with over 3 million Pis sold worldwide, the Foundation unveiled the Raspberry Pi Model B+, a $35 final board revision incorporating numerous improvements requested by the ever-growing Pi community.

The following table shows the difference between the Raspberry Pi models: