Raspberry Pi A, User Manual, Page: 271 / 314

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The design and layout of the Prototyping Pi Plate will be familiar to anyone who has used an
Arduino microcontroller. An add-on board with the same footprint as the target device,
designed to connect to on-board headers and sit above the surface of the original board is a
common sight in the Arduino world, where such add-on boards are known as
shields . The
idea for the Prototyping Pi Plate, in fact, comes from Adafruit’s self-designed Protoshield
add-on for the Arduino.
As a full-coverage add-on board, the Pi Plate is designed to connect to the GPIO header and
cover the entire surface of the Pi. This positioning above the Pi can make it difficult to access
the DSI video output and MIPI CSI-2 camera input connectors, although longer ribbon cables
should route beneath the Pi Plate without trouble. If you’re planning to use an add-on cam-
era module (see Chapter 15, “The Raspberry Pi Camera Module”) or DSI-connected display,
be sure to check the length of ribbon cable provided before planning your project around the
Pi Plate.
The prototyping surface of the Pi Plate is split into two, with both halves offering through-
hole construction in common 2.54 mm spacing. The first half of the prototyping surface is
set up in a similar way to a breadboard: copper tracks on the underside link rows together,
and a central bus in the middle provides common power and ground connectivity. The sec-
ond half of the prototyping surface does not have such tracks, allowing more custom circuits
to be constructed. Overall, the surface provided for circuit creation is significantly larger
than that of the Slice of Pi, making the Pi Plate suitable for more-complex projects. It addi-
tionally offers an
SOIC surface , designed for soldering a surface-mount component for parts
that aren’t available in through-hole format.
Thanks to its large size, you can also use the Pi Plate with a quarter-size breadboard (sold in
the Adafruit shop as a “tiny breadboard”). This small, two-section breadboard comes with a
self-adhesive foam backing and can be stuck to the top of the Pi Plate over the prototyping
area (see Figure 16-5). Doing so means that it’s impossible to use the prototyping area to
make a permanent circuit, but the combination offers a self-contained add-on for rapid tem-
porary prototyping of smaller circuits.
As with the Slice of Pi, the Prototyping Pi Plate is at heart a basic device. The kit contains no
active components, but simply headers, terminals and the board itself. As a result, it pro-
vides little extra protection for the Pi’s GPIO ports beyond making it more difficult to acci-
dentally short-circuit two connections. Unlike the Slice of Pi, the Pi Plate provides access to
all 26 of the Pi’s GPIO header pins—meaning that you could accidentally connect things to
the pins marked as Do Not Connect on the GPIO header diagram (see Chapter 13, “Learning
to Hack Hardware”). As with connecting things to these pins directly, this is inadvisable and
can result in permanent damage to the Pi.