The Raspberry Pi B version is one of the most popular hacker toys of the day and with good reason. Although it’s not the first sub-miniature single-board computer, it’s the first one whose price, performance, features and power make it an acceptable substitute for a “real” desktop computer.
But there’s another Raspberry Pi as well. Ironically, the “A” model came out after the “B” model. Unlike the “B”, it lacks a few things. Only one USB port and no on-board ethernet, for example.
But before you dismiss it as not worth the $10 lower price, here are some things to consider:
1. The “A” model pulls less power, since it doesn’t have to support those missing components. This is especially important if you want to run the unit off batteries or solar cells.
2. The ethernet controller on the B is actually just a third USB port with an on-board USB-ethernet adapter. If I need to add ethernet to an “A” board, I have a USB ethernet dongle sitting on the shelf right next to me. I originally bought it to network-enable an old laptop.
3. Some people prefer NOT to have critical machines on the Internet. Why pay for hardware you don’t want to use? Plus these days, a lot of people skip the wiring and use WiFi adapters. There are a number of WiFi dongles that will plug into the USB port. Why pay extra for a jack you don’t need? Or for power to support it?
4. Enough about networking, though, consider USB. For some people 2 USB ports are more than they need. So the single port on the “A” system may be sufficient or even surplus. Conversely, for some people, 2 ports are not enough. And/or they need powered ports with more power than the Raspberry Pi itself supplies. USB expansion hubs, both powered and un-powered have been around a long time and are easy to come by.
So we have 2 choices. A good general-purpose platform and a cheaper basic platform. Both expandable, both economical in their own ways.