Three years ago today, a credit-card sized computer was released by the Raspberry Pi Foundation. While we remember it well, it seems like ages ago that the original arrived, and changed single board computing forever. For a mere $35 and a few common peripherals, kids, adults, teachers and tinkerers could have a fully functioning Linux computer with which to do whatever they liked. Play games, learn to code, or interact with sensors, screens and switches. From there, an entire ecosystem evolved around the board. Prominent GPIO pins allowed for a multitude of add-on boards to fit virtually any need, and uses for the Pi were expanding at a rapid pace. Home theater media centers, time-lapse camera rigs, weather balloons, and bitcoin mining clusters became common projects built with the Pi.
In the beginning
The Model B was launched on February 28, 2012 and is the most popular version of the Raspberry Pi to date, with millions of boards sold worldwide. For $35, the Model B came with 256MB RAM, and several ports, including an ethernet jack, audio jack, 2 USB ports, RCA jack, HDMI out and 26 GPIO pins.
A few months later, in May, the Raspberry Pi Foundation, listening to feedback, implemented several changes in the form of the Model B Rev 2.0. Changes included a reset circuit, removal of the resettable fuses found on Rev 1 boards, making it possible to reliably power the PI from a USB hub that back feeds power. Additionally, two mounting holes were added to the board and some GPIO changes were made.
On October 15, 2012, the Model B was upgraded to 512MB RAM - double the current offering and required updated firmware.
Another model arrives
On February 2, 2013, the Foundation released the first additional model in its line; the Model A. The board was a stripped down version of the Model B, coming with only one USB port, no ethernet jack and 256MB RAM. These changes allowed for the board to sell at $10 less than the Model B, at $25. An additional perk included much lower power consumption (roughly a third of the B).
During the course of 2013, the Foundation released two add-on boards in the form of cameras for $25 each. After a reported year of development, the original camera launched April 14 and attached to any Pi via a ribbon cable. After enabling the camera in the Pi's operating system, photos and HD video were able to be captured by the Pi. The cameras supported 5MP photos and 1080p30, 720p60 and 640x480p60/90 video recording. This marked the first add-on board released by the Foundation. Later, on October 28, an additional camera, called the Pi NoIR, was released. As the name suggested, this camera came without an "IR cut filter", which enabled photography/videography at night.
Pi gets smaller
In 2014, the foundation launched a new spin on the Raspberry Pi. The Pi was being used in more and more "finished" projects and embedded designs. For this reason, the Compute Module was released. Aimed at businesses and industrial users, the Compute Module had the guts of the Raspberry Pi (the BCM2835 processor and 512MB of RAM) as well as a 4GB eMMC Flash device (which is the equivalent of the SD card in the Pi). The Compute Module was primarily designed for those who are going to create their own PCB. The Compute Module could be programmed via the Compute Module IO Board, which was released as part of the Raspberry Pi Compute Module Development Kit. The module was offered for around $40 individually, or $215 for the entire dev kit.
A major change
On August 14, 2014, the Raspberry Pi Model B+ was released. Released as "not a 'Raspberry Pi 2', but rather the final evolution of the original Raspberry Pi", it was sold a the same $35 price tag. The B+ came with two additional USB ports, for a total of four, 14 more GPIO pins for a total of 40, 1GB RAM, micro SD slot, lower power consumption, better audio, and neater form factor. The new form factor required a different case, and some add-on boards were affected by the additional GPIO pins.
In the same fashion as the Model B, the board that followed the B+ was the Model A+. The A+ was released on November 11, 2014. The A+ had a smaller footprint than the prior Pis, cutting almost an inch off the length of the board. It came with 256Mb RAM, 1 USB port and no ethernet jack, similar to the original Model A. The most groundbreaking aspect of the board though, was the price. It was introduced at a mere $20. That, combined with the smaller size made it the least expensive, smallest single board computer in the world at the time of release. The Model A+ was made in limited quantities.
The next generation of Pi
On February 2. 2015, the Foundation released the Raspberry Pi 2 Model B. The Pi 2 had the same footprint and port locations as the Pi Model B+. Major differences included the addition of a quad core processor, instead of the single core found on the B+, and 1GB RAM instead of 512MB. By moving to a quad core processor, speeds of up to 6x faster than previous Pis were possible. With these updates, the Pi 2 Model B was the largest single step evolution of the Raspberry Pi, but still retained the $35 price. An updated OS was released to work with the new board, and Microsoft has plans to release a Windows 10 OS free of charge.