Electronic Equipment - Raspberry Pi User Manual

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IN EARLIER CHAPTERS,
platform for running a variety of software . In this, it's not alone: any desktop or laptop can
run the same software, and in many cases run it far faster than the Pi's low-power processor
can manage .
The Pi has another trick up its sleeve, though, which places it above and beyond the capabili-
ties of the average PC: its 26-pin general-purpose input-output (GPIO) port, located on the top-
left of the Pi's printed circuit board .
The GPIO enables the Pi to communicate with other components and circuits, and allows it to
act as a controller in a larger electronic circuit . Through the GPIO port, it's possible to have the
Pi sense temperatures, move servos and talk to other computing devices using a variety of dif-
ferent protocols including Serial Peripheral Interface (SPI) and Inter-Integrated Circuit (I²C) .
Before you can get begin building circuits to use with the Pi's GPIO port, however, you're
going to need some additional equipment .

Electronic Equipment

To start building circuits that can be controlled by the Pi's GPIO port, you'll need various
components and tools . The following list provides a sample shopping list for getting started
with electronics:
R A S P B E R R Y P I
❍ Breadboard—An electronic breadboard provides a grid of holes spaced at 2 .54 mm
intervals into which components can be inserted and removed . Below each grid is a
series of electrical contacts, which allow components in the same row to be connected
together without wires . A breadboard is a valuable tool for electronics work, because it
allows you to quickly make mock-up circuits that can be modified without needing to
be soldered or desoldered .
❍ Wires—While a breadboard allows some components to be joined without wiring,
you'll still need wires to connect one row to another . These are known as jumper wires,
and if you're working on a breadboard, it's a good idea to get solid-core wire rather
than stranded-core wire . Solid-core wire is easier to insert into the breadboard's holes
compared to stranded . It's also helpful to get various colours, so you can colour-code
each connection according to its purpose .
❍ Resistors—The vast majority of electrical circuits make use of components called resis-
tors, and the example projects in this chapter are no exception . Resistors are measured in
ohms, written as the symbol Ω . Always try to have a handful each of a variety of common
values: 2 .2 KΩ, 10 KΩ, and 68Ω are good values to start with . Some retailers carry resis-
tor kits, which include a wide range of useful values .
U S E R G U I D E
you learned how the Raspberry Pi can be turned into a flexible