4MB/sec Class 6: 6MB/sec

Class 10: 10MB/sec

You’ll find that opinions vary widely regarding which SD card brand(s) or speed(s) is optimal. My best advice to you is to try out a few models and speed ratings with your equipment and let your own intuition and Pi benchmark results be your guide.

Standard-sized SD cards come in two varieties: Secure Digital High Capacity (SDHC) and Secure Digital eXtended Capacity (SDXC). The main difference is that SDHC cards go up to 32GB, and SDXC cards go up to 2TB. If I were you, I would check the Raspberry Pi compatibility list at http://is.gd/Ym6on0 before I shell out the money for a top-of-the-line, highest-capacity, speediest card. Sometimes it is best to go for compatibility instead of potential performance.

Powered USB Hub

The Model B board includes two USB ports, but please don’t let that “security” lull you away from the reality that you truly need to purchase a powered USB hub. Some Raspberry Pi newcomers use the two USB ports for keyboard and mouse connections and then scratch their heads in wonderment

when they realize, “How the heck can I plug in something else to the Pi?”

A hub is a compact device that hosts several USB A-type devices. The “powered” part is important inasmuch as USB hardware has in itself a current draw. Thus, we need to ensure that our USB hub can supply not only the 700 mA required by the Pi board, but also any power requirements for USB-attached peripherals.

Actually, that point bears repeating: Ensure that any power supply that you consider for your Pi supplies at least (but hopefully more) than 700 mA. Non-self-powered USB peripherals will each draw 100 mA or so from the USB ports on your Pi. To be sure, you should consider a powered USB hub as a “must have” peripheral for your Pi.

Something else: The power supply and a powered USB hub are two separate pieces of hardware and serve different purposes. The USB power supply gives power to the Raspberry Pi itself and allows it to function. A powered USB hub enables you to expand the Pi’s functionality by adding more hardware and giving power to those additional devices rather than to the Pi.

You can see what my own powered USB hub looks like by examining Figure 2.3.

Ethernet Cable

If you want to connect your Pi to the Internet (and why wouldn’t you want to do that?), you’ll need an Internet connection and a Category 5e or 6 Ethernet cable. The Model B board includes an onboard RJ-45 Ethernet jack, into which you plug your new cable. You plug the other end of the cable into a free switch port on your wireless router, cable modem, or Internet connectivity device.

Note: Connectors and Ports

In physical computing, a port or jack is the connection interface on the computer. The perimeter of the Raspberry Pi, for example, is lined with ports of different varieties.

A plug or connector is the part of a cable that plugs into a port. For instance, a Category 6 Ethernet cable uses an RJ-45 connector to plug into the RJ-45 jack on the edge of the Raspberry Pi Model B board.

“But what about Wi-Fi?” you ask. Wi-Fi and all other network-related questions are addressed in Chapter 7. For now, understand that if you have a Model A board, your only option for traditional wired Ethernet networking is to purchase a USB wired Ethernet adapter. Again, more on that subject later on in the book.

The subject of Wi-Fi connectivity bears on what we just covered vis-a-vis USB ports and powered USB hubs. That is to say, we must use a USB Wi-Fi dongle in order to give wireless Ethernet connectivity to our Raspberry Pi device.

Monitor

Unless you plan to run your Raspberry Pi remotely in a so-called headless configuration, you need to set aside a spare monitor or television for use with your Pi. Yes, you heard me correctly: You can plug your Pi into any television, be it an older model (via an old-school yellow RCA plug) or a modern HD display using the HDMI interface.

In fact, one of the Raspberry Pi Foundation’s goals in designing the Pi was to support “any old”

television set as a cheap display device. Remember that the Foundation’s philosophy is to make the Raspberry Pi as inexpensive and easy as possible for people to get their hands on and to start

Depending on what type of monitor or TV you have at your disposal, you might need to purchase an analog RCA video cable or a digital HDMI cable. The good news is that these cables are almost ubiquitous and are quite inexpensive.

As you learn in more detail momentarily, the use of an HDMI cable means that you don’t have to worry about providing audio-out capability in your Pi with an analog audio cable. However, if you’re using the RCA video cable and do need audio, you’ll need to buy a 3.5mm stereo audio cable as well.

Note: HDMI with Dedicated Audio

In case you were wondering, it is possible to configure the Raspberry Pi to use the HDMI cable for video and the 3.5mm stereo audio cable for audio. To do so, you must instruct the Pi to disable the HDMI audio channels by running the command sudo amixer cset numid=3 1 from a Raspbian shell prompt. By the way, Raspbian is the official Linux distribution of the Raspberry Pi; we’ll learn all about it beginning in Chapter 4.

USB Keyboard and Mouse

The good news is that the power draw for USB keyboards and mice is low enough that you can plug them directly into the USB interfaces on the Model B board. The bad news is that you won’t have any additional expandability for your Pi. Therefore, your best bet is either to invest in the previously described powered USB hub or connect to your Pi remotely.

Figure 2.4 shows a Raspberry Pi all plugged in.

FIGURE 2.4 A Raspberry Pi, fully connected and ready to go!

Caution: Just in Case

As you can see in Figure 2.4, a “naked” Raspberry Pi, especially when it’s all cabled up, is quite vulnerable to your physical environment; this includes electrostatic discharge (ESD) as well as physical factors. For these reasons you should consider purchasing a case for your Pi. You read about cases in more detail in Chapter 3, “A Tour of Raspberry Pi Peripheral Devices.” Even with a case, however, you should take steps to avoid ESD when interacting with the Pi hardware. You can do this by using an antistatic wrist strap whenever you handle the bare Pi board.