The-MagPi-issue-14-en.pdf

I ISSUE14 - -JUL2013

G e e t tp r r i in t t e ed c cop i i e e s s

a a t t t th e em a agp i i . . c com

A Magazine for Raspberry Pi Users

I I / /O a and l log i i c c e e x xp a an s s i ion

Robo t t i i c c a a r rm c con t t r ro l l

P a a r r a a l l l l e e l lp r ro c c e e s s s s i ing

Boo t t c c a amp r r e epo r r t t

LEDm a a t t r r i i x x

Ch a a r rm

J JAVA

Th e e c c a am e e r r a a

modu l l e e

Win a 512MB

Raspberry Pi

& interfacing

goodies

R a a s spb e e r r r r y yP i i i i s s a a t t r r a ad e em a a r r k ko f fTh e eR a a s spb e e r r r r y yP i iFound a a t t i ion . .

Th i i s sm a ag a a z z i in e ew a a s s c c r r e e a a t t e edu s s i ing a aR a a s spb e e r r r r y yP i i c compu t t e e r r . .

h t t t tp : : / / / /www . . t themagp i i . .com

Welcome to the 1 4th issue of The MagPi - another fully loaded guide to all things Raspberry Pi!

This month we begin our journey in introducing the newest module in the Raspberry Pi world, the

camera, with a great guide written by James Hughes on setup and basic operation. The conclusion of

this article will be found in next month's edition where James builds on these foundations with hints and

tips on advanced usage.

We reload the Matrix with part two of the interesting Pi Matrix article, take a look at the Guzunty board

and review the ever popular South West Raspberry Pi Boot Camps.

We bring you more on the programming languages Charm, Scratch and Python plus bring you the first

MagPi article on the popular language, Java.

I am pleased to report that all pre-order Volume 1 MagPi bundles ordered via Kickstarter or

themagpi.com have now shipped. We will soon have individual issues coming to print. We hope you

enjoy the printed editions and thank you again for your support and patience in helping make the dream

a reality.

Ash Stone

Chief Editor of The MagPi

The MagPi Team

Ash Stone - Chief Editor / Administration / Proof Reading

W.H. Bell - Issue Editor / Layout / Graphics / Administration

Bryan Butler - Page Design / Graphics

Ian McAlpine - Layout / Tester / Proof Reading

Chris 'tzj' Stagg - Tester

Colin Deady - Layout / Proof Reading

Matt Judge - Website / Administration

Aaron Shaw - Layout

Shelton Caruthers - Proof Reading

Meltwater - Proof Reading

Sai Yamanoor - Tester

James Nelson - Proof Reading

Adrian Harper - Layout

Paul Carpenter - Tester

Dave Allan - Tester

Claire Price - Proof Reading

Phil Tesseyman - Tester

Steve Drew - Layout

Contents

RASPBERRY PI CAMERA MODULE

Part 1 : Getting to grips with the camera module

PYTHON CONTROL: ROBOTIC ARM

Controlling the Maplin robotic arm with Python

12 MUNTS I/O EXPANSION BOARD

Using an ARM Cortex-M0 microcontroller

BUILD A GUZUNTY PI

Make a low cost hardware expander

PI MATRIX PART 2

Control individual LEDs and give the Pi Matrix a workout

THIS MONTH'S EVENTS GUIDE

Barnsley, Lima, Singapore, Liverpool

RASPBERRY PI BOOT CAMPS

What are the ingredients for a fun filled family Pi day?

CHARM PART 3

Charm syntax and semantics

FRESHLY ROASTED

A beginners guide to Java

THE PYTHON PIT

Using a simple client-server model for parallel calculations - part 3

COMPETITION

Win a 51 2MB Model B Raspberry Pi and interfacing goodies!

FEEDBACK

Have your say about The MagPi

Boot Camp photographs on pages 3, 22 and 23 by Alex Sheppard

Prototype camera mount on the front cover is courtesy of Grasping Hand

http://www.themagpi.com

BASIC OPERATION

Getting to grips with the camera module

The Raspberry Pi camera - part 1

James Hughes

DIFFICULTY : BEGINNER

Guest Writer

A few weeks ago, the Raspberry Pi Foundation

launched their first peripheral, a 5MP camera.

Priced at $25, the same price as the model A, it’s

a very small PCB on which is an Omnivision

OV5647 camera module. It connects to either the

Model A or Model B Raspberry Pi using a 1 5cm

1 5 way ribbon connector.

image taking tasks. Firstly though, a description

of how the camera module came to be...

History

From its first launch the Raspberry Pi has had a

connector on it to attach a camera to the GPU

(the VideoCore 4 Graphics Processing Unit on

the Raspberry Pi). This connection uses the CSI-

2 electrical protocol and is a standard used in

most mobile phones. It is an extremely fast

connection, which on the Raspberry Pi is

capable of sending 1 080p sized images

(1 920x1 080 x1 0bpp) at 30 frames per second,

or lower resolution at even higher frame rates. It

had always been intended at some point to

release a camera module that could use this

connection, as the ability to stream high speed

video data through the GPU without any

interaction with the ARM processor would always

make the camera much more efficient than any

USB attached webcam. It would also enable the

use of the GPU’s ability to encode H264 video,

or JPEG images in hardware.

Over the course of this series I will take you

through initial connection of the camera to your

Raspberry Pi and will show you some of the

basic commands used to take both still and video

imagery. At the end, some of the more

sophisticated features will also be explained. Not

every option will be covered (new options are

being added all the time so it’s difficult to keep

up) but hopefully this article will give enough

information for you to be able to cover most

It turns out that productising a tiny PCB like the

camera board is not a quick task! The prototype

was re-designed to remove some unnecessary

components, but more importantly, to move the

camera crystal, used for timing, to the PCB itself.

eachendoftheconnector.

Electromagneticcompatibility(EMC)testinghad

shownthatthe25Mhzclockprovidedbythe

GPUcausedtoomuchinterferenceasitpassed

uptheribboncabletothePCB.Addingacrystal

tothePCBitselfstoppedthisinterference.A

couplemoreboarddesignslater,tohelpwith

productionlinemanufactureandtesting,and

eventually,aboutayearafterthefirstprototypes,

theproductionboardwasready.

Meanwhile,workhadbeenongoingtowritea

coupleofapplicationstomakeuseofthe

camera,toupdatetheGPUfirmwaretosupport

thecamera,andtoimprovethecameratuningas

thebasictuningalreadyinplacehadanumberof

obviousdefects.

Itshouldslideupeasily,andbeabletopivot

aroundslightly.Fullyinserttheribboncableinto

theslot,ensuringitisstraight,thengentlypress

downthetabstoclipitintoplace.Thecamera

PCBitselfalsorequiresyoutopullthetabsaway

fromtheboard,gentlyinsertthecable,thenpush

thetabsback.

Cameratuningisacomplextask,whichhas

beencoveredontheRaspberryPiwebsite,soI

won’trepeatithere.Sufficeittosay,theend

resultsarewellworththeextraeffortputinby

DavidPlowmanwhileatBroadcom.Thanks

David.

So,withthehistoryoutoftheway,let’stakea

lookatgettingyourcameragoing.

Settingup

Firstly, it’simportanttostartwithawarning.

Cameraslikethesearestaticsensitive.You

shouldearthyourselfpriortohandlingthePCB(a

sinktap/faucetorsimilarshouldsufficeifyou

don’thaveanearthingstrap).

Thereareonlytwoconnectionstomake,the

ribboncableneedstobeattachedtothecamera

PCBandtheRaspberryPiitself.Youneedtoget

ittherightwayroundorthecamerawillnotwork.

OnthecameraPCB,thebluebackingonthe

cableshouldbeawayfromthePCB,andonthe

RaspberryPi itshouldbetowardstheethernet

connection(orwheretheethernetconnector

wouldbeifyouareusingamodelA).

ThePCBconnectorisalittlemoreawkwardthan

theoneonthePi itself.Thereisavideoat

http://youtu.be/GImeVqHQzsE whichshowsthe

connectionsbeingmade.

So,wenowhavethehardwareallattached,we

nowneedtomakesurewehavethecorrect

softwareinstalled.Asexplainedabove,thereare

somecommandlineappstoinstall,anda

firmwareupgradewiththecameradriverand

tuningtoinstall.Thisprocessmaynotbe

necessaryinfutureasnewerdistro’sare

AlthoughtheconnectorsonthePCBandthePi

aredifferent,theyworkinasimilarway.Onthe

RaspberryPi,youneedtopullupthetabson

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