By Doug Lowe

Since the introduction of the original Raspberry Pi back in 2012, an almost dizzying array of versions has been released. The Raspberry Pi has been through three generations, known as 1, 2, and 3. Each new generation has incorporated new features.

The Raspberry Pi 2 was introduced in 2015. It improved upon the Raspberry Pi 1 by using a more powerful processor and additional RAM, while holding the price the same. Importantly, the Raspberry Pi 2 also increased the number of GPIO ports from 17 to 26. Unfortunately, in doing so the GPIO pin configuration was changed, which means that projects created for the Raspberry Pi 1 are not compatible with projects created for the Raspberry Pi 2.

In 2016, the Raspberry Pi 3 was introduced. It improved upon the Raspberry Pi 2 by adding a more powerful processor, faster RAM, and built-in wireless networking. (Wireless networking with a wireless Raspberry Pi 2 was usually done using a wireless adapter inserted into one of the USB ports.)

The price of all three versions of the Raspberry Pi has been $35.

The first-generation Raspberry Pi 1 was available in two models: Model A and Model B. The Model A version was a slimmed-down version of the Model B, with less memory and fewer I/O options but consuming less power. In 2014, these two models were replaced with the Model A+ and Model B+, which added additional capabilities.

One of the main differences between the Model A+ and Model B+ is that the Model A+ does not have built-in networking. Because connecting to a network greatly simplifies the task of configuring your Raspberry Pi, avoid the Model A+ until you’ve gained some experience working with the more powerful Raspberry Pi models.

Note that versions 2 and 3 of the Raspberry Pi are not available in A or B models.

The original Raspberry Pi 1 models (both A and B) had fewer GPIO pins than the newer versions. The original versions provided a 26-pin header block that provided access to 17 GPIO ports. On the newer versions, including the Raspberry Pi 2 and 3 models, a 40-pin header provides access to 26 GPIO ports.

If you don’t yet own a Raspberry Pi, and you’re planning on working on your own electronic gadgets, you should purchase a Raspberry Pi 3 as part of a kit that includes the materials you’ll need to get started. These simple kits include a power supply to power your Raspberry Pi, a microSD card already loaded with the operating system software, and a small book to get you started. Some kits include additional goodies, such as an HDMI cable to connect your Raspberry Pi to a monitor and perhaps additional components such as LEDs, resistors, jumper cables, and a breadboard.