Raspberry Pi A, User Manual, Page: 221 / 314

C H A P T E R 1 3
L E A R N I N G T O H A C K H A R D W A R E
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Push-buttons —A very common input component, a push-button completes an electri-
cal circuit when pushed. At the most basic level, a keyboard is little more than a collec-
tion of push-buttons. If you’re designing a circuit to provide a simple input to the Pi,
pick the button labelled
momentary switch .
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LEDs — Light-emitting diodes (LEDs) are the most common output device in existence.
An LED lights up when voltage is applied, giving you visual feedback on whether a pin
on the Pi’s GPIO port is high or low. When you’re buying LEDs for use with the Pi, opt
for low-power ones. The GPIO port isn’t that powerful, and high-current LEDs—such
as bright-white or bright-blue models—will require an external power supply and an
extra component known as a
transistor .
Additionally, if you’re planning on making something more permanent once you’ve finished
your breadboard prototype (which you’ll learn about later in this chapter), you’ll also need
the following:
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Stripboard —This can be thought of as a single-use breadboard. As with breadboards,
holes are arranged in a 2.54 mm grid. Unlike breadboards, the components need to be
soldered into place—after which you’ve got a permanent electronic circuit.
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Soldering iron —When you need to connect a component permanently into a circuit,
you need to solder it. You don’t have to spend a fortune on a soldering iron, but if your
budget stretches to a temperature-controlled model, it’s a wise investment. Make sure
any soldering iron you buy has a small, pointed tip—chisel-tip irons aren’t suitable for
delicate electronic work.
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Solder —Your soldering iron needs solder. Solder is a mixture of conductive metals
mixed with a cleaning substance known as flux. Make sure the solder you buy is suit-
able for electronics work—thick, plumbing solder is cheap but may damage delicate
circuits, because it requires too much heat to melt.
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Stand and sponge
—It’s important to have somewhere to put the hot soldering iron
when it’s not in use, and a way of cleaning the tip of the iron while you’re using it.
Some soldering irons come with a stand with a built-in cleaning sponge—if yours
didn’t, buy a separate stand-and-sponge set.
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Side cutters —Through-hole components have long legs, which are left sticking out
after you’ve soldered them in place. Side cutters allow you to cleanly and quickly trim
these excess legs without damaging the solder joint.
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Tweezers —Electronics components can be small and fiddly, and a good pair of twee-
zers is invaluable. If you’re thinking of using surface-mount components, instead of
the easier-to-solder through-hole components, tweezers are an absolute necessity—
without tweezers, you’ll burn your fingers if you try to hold the component and solder
it at the same time!