Micro Mart - 10 March 2016_

66 Issue 1404

A

O

g

d

h

j

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b

f

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David Briddockmeanders

throughRaspberryPitechnology

from Ato Z

Today there are scores

of add-on boards available,

catering for a wide cross-

section of activities





Alphabet Pi:

F

ollowing the phenomenal success of the first Raspberry Pi, the

$35 Model B, the Raspberry Pi Foundation was keen to attract

an even wider audience by offering a lower-cost entry point. In

2013, it launched the $25 Model A, aredesigned board with fewer

components to shave down manufacturing costs.

Obvious visual differences include the lack of an RJ45 Ethernet

socket and areduction in the number of USB sockets from two to

one. The board also had only 256MB of RAM – half the second-

edition Model B, but the same as the original Model B.

But these omissions provide certain advantages.Without the

bulky RJ45, the Model A has a much slimmer profile and significantly

reduced power consumption. In fact, a Model A runs on abouta

third of the powerrequired by a Model B. These attributes are highly

attractive to anyone building mobile and battery-powered projects,

such as radio-controlled androbotic vehicles.

ModelA+

Afterreceiving positive feedback from the Model B+ initiative in

2014, the Raspberry Pi Foundation decided to give the Model A a

similar design makeover. The price wasreduced too, now down to

just $20.

Named the Model A+, it shares a number of features with the

Model B+. For example, it has the same 40-pin General Purpose

Input Output (GPIO) connector, the sturdier micro-SD card socket and

four mounting holes. Power consumption levels were lowered still

further, and the audio output benefited from a dedicated low-noise

power supply.

Most interestingly for the maker community, theredesigned

layout, which involvedrepositioning the USB socket and 3.5mm

audio jack, means the Model A+ board is actually 2cm shorter than

the Model A.

Add-onBoards

The amazing success of the Raspberry Pi and its versatile GPIO

connector has encouraged many thousands of owners to experiment

with electronic circuitry. They’ve added LEDs, buttons, joysticks,

sensors, motor controllers, analogue-to-digital convertors, mini-LCD

displays and much more.

Electronic designers noticed what was going on andrecogniseda

business opportunity. They began to create a range of add-on boards

that simply snapped onto the Model B or Model A using the 26-pin

GPIO connector. The idea was to provide newbies an easier entry

point into the world of hardware hacking.

Add-on boards help Pi owners create home automation systems,

build a security camera, construct a weather station or controla

motorisedrobot. Many also offer built-in current protection, which

ensures a circuit can’t be accidentally overloaded and damage the

Raspberry Pi.

Today there are scores of add-on boards available, catering fora

wide cross-section of activities and projects. Some popular examples

are the Pibrella (pibrella.com), PiFace (piface.org.uk), PiLite (goo.

gl/ioE4C3) and Adafruit’s Pi Cobbler Breakout kit (goo.gl/tLf6b).

However, the introduction of the 40-pin GPIO connector, for the

Model B+, Model A+ and Pi2, changed the game, as it led to the

related Hardware Attached OnTop (HAT) initiative. Snap on a HAT

and the Pirecognises which board is attached, then automatically

loads the appropriate drivers and setup files. Now board designers

can open up Pi hardware hacking to an even wider audience.mm

Model-A