Raspberry Pi for Kids: Understanding Pi Extras

By Richard Wentk

When you buy a Raspberry Pi, you get a small circuit board. And that’s it. On its own, the board does nothing. You can’t do anything with it, except look at it, and maybe play catch, which is fun but not what it’s made for.

To turn a Pi board into a working computer, you have to add some extras. Collecting all the extras and connecting them to the Pi is your first project. And it’s a big one!

Deciding whether you need a hub

Are you getting a Pi 2? You don’t need a hub. Did you get an old Model A+ or B+ board? You don’t need a hub either.

Otherwise, there’s something you need to know: the original A/B models had a problem: If you plugged a keyboard and mouse into the USB connectors, the Pi often stopped working.

The following figure shows how you have to fix this issue by connecting everything to the Pi, including a keyboard, and mouse, through a USB hub.

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The hub has to have its own separate power supply. The hub solves the problem, but leaves you with a big mess of wires and connectors and stuff.

The A+/B+/2 models work fine without a hub, as shown in the following figure. This makes them easier to set up. They don’t need so many wires and cables.

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A hub is a box with plenty of USB connectors. You plug one end into a single socket on the Pi, and then you plug all your other USB extras into the hub. If the hub has its own power supply, it makes sure that everything gets the power it needs.

If you plug things that use a lot of electricity to whirr or flash, like robot motors and killer lasers, you need a hub even on a Model A/+ and B+. Small things like keyboards and mice don’t need one.

Choosing a mouse and keyboard

You can use any mouse or keyboard with a USB plug. Models with a cable should just work. You can probably use wireless models, as long as they come with a USB receiver dongle. (Anything made by Logitech should work.) Bluetooth mice and keyboards probably won’t work.

You don’t need to spend a lot of money on these extras. Basic models are fine.

Choosing a monitor or TV

The best way to connect the Pi to a monitor is to use the HDMI socket. Most new TVs and many monitors have an HDMI socket that takes an HDMI cable. Hook up the cable to the Pi at one end and the monitor or TV at other, and you’re done.

The following figure shows where the HDMI connector is.

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The monitor/TV doesn’t have to be very new, or very good. The Pi can barely produce HD video. Almost any monitor less than ten years old should work fine.

A few monitors have a different socket called a DVI-D connector. If you can’t find a monitor with HDMI, you need an adaptor cable with an HDMI plug at one end and a DVI plug at the other. Look on Amazon and eBay for a cheap one.

If your monitor has only a VGA connector, you need a special adaptor and a cable. Amazon and eBay should help again, but you may as well see whether you can find a used new or used monitor with the right connections. It may be cheaper than an adaptor.

The Big Yellow Socket on the Model A/B Pis can work with an old-fashioned analog TV — the kind that lives in a huge wooden box with a heavy thick glass screen. Most people don’t use them anymore. You shouldn’t either because the picture will be very fuzzy, and you won’t be able to read words on the screen.

You don’t really need a monitor at all because you can control a Pi remotely from another computer. This is called running headless — not because you can do it without your head, but because you don’t need a monitor, mouse, or keyboard. (These are just like the Pi’s head, kind of, if you use your imagination.) Setting up a headless Pi is kind of complicated, especially if you’re just starting out. It works differently on a Mac and a PC. If you’re curious, search the web for Headless Raspberry Pi. You probably won’t be able to get it working until you’ve spent more time with your Pi.

Recognizing cables and connectors

Wait — USB? VGA? DVI? HDMI? What do all these letters mean? If you don’t already know, search the web to find out!

You don’t need to remember the names of all the cables, but you do need to be able to tell them apart so that you know which cable goes where on the Pi. The following figure shows the network/Ethernet and USB connectors on the side of a B+ board.

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Choosing a memory card

The Pi doesn’t have a disk drive. It stores everything on a small memory card. The Model A or B needs an SDHC card with a speed rating of 8 or 10. For a Model A+/ B+/2, get a microSD card.

The following figure shows the bottom of a Model B+. The memory card is the black rectangle at the right.

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The card should hold at least 4GB. You can get a bigger card if you like, but it will cost more, and most of the space will be wasted.

Some MicroSD cards come with an SDHC adaptor. If you get one of these you can use the same card in older A/B and newer A+/B+ Pi boards.

Finding memory cards

The cheap option is to get a blank card — Amazon is a good choice — and write the software to the card by hand. You can only do this if your Mac or PC has a card reader/writer. If it doesn’t, you’ll have to buy one for about $5 to $10 (less than £10 in the UK).

The lazy option is to buy a card with the Pi software already installed. The software is called NOOBS. You can buy prewritten cards from Amazon and shops that specialize in Pi extras. The cards cost a few dollars or pounds more, but they save you some time.

Finding a power supply

Although the Pi is cheap to run, it needs a special power supply and a special cable. The power connector on the Pi is a tiny microUSB socket, and it needs a matching plug. The socket grips the power cable hard so that you can’t pull it out by accident.

You can use a standard USB power supply as long as it’s 2A, 2.1A, or 2100mA. This means it produces plenty of spare power. If it isn’t labeled 2A, 2.1A, or 2100mA, your Pi may not work properly.

The best way to find a power supply is to look for Raspberry Pi Power Supply online. Don’t forget to look for the 2A tag!

Some cheaper supplies are labeled 1500mA or 1.5A. They’ll ­probably work, until you start plugging in lots of extras. It’s worth spending a little more and getting more power. Some Apple iPad adaptors produce 2.4A. That’s even better than 2.1A. If you have one, you can use one.

Other cables

You’ll probably need a network cable, which is sometimes called an Ethernet cable. The cable should be Cat 5 or Cat 6. Plug one end of the cable into your home Internet router and the other into the network socket on the Pi.

If you want to plug more than one Pi to a home network, buy a long cable and a network switch — a box with lots of network ­sockets. Plug the long cable into one of the sockets and other computers into the other sockets. The other end of the cable goes into your home router. (If this is too hard, ask a grown-up to help you. If you can’t find a grown-up to help, search the web!)