raspberry pi

Raspberry Pi.. what we have learned so far ..

Copyright © 2012-2013, Wolf Paulus. A Tech Casita Production. All rights reserved.

http://wolfpaulus.com



General Purpose Computer

Headless Server

Embedded System


Model B


“From a position in the mid-1990, when 17-year-olds came to the University with a grounding in several computer languages, hardware hacking, and often even with assembly language, we gradually found ourselves in a position where, by 2005, these kids were arriving having done some HTML - with a bit of PHP and Cascading Style Sheets if you were lucky.”

Why ?

RaspberryPiPrototype Model A


May 2011 Video of the Raspberry Pi, recorded by tech journalist Rory Cellan-Jones with his phone, goes viral.

Feb 29th 2012Google shows more searches for “Raspberry Pi” than “Lady Gaga” andhardware suppliers’ Websites crash under the load of up to 7 orders per second.

June 2012 Raspberry Pi User Forum has 20K members who have written more than 100K posts.

Feb 2013 One Million Raspberry Pi sold

H!tory


Model B


Model A


• AROS

• Android 4.0 (Ice Cream Sandwich)

• Arch Linux ARM

• Debian Squeeze

• FreeBSD

• Firefox OS

• Gentoo Linux

• Google Chrome OS

• NetBSD

• Raspberry Pi Fedora Remix

• Open webOS

• Raspbian (Debian Wheezy port with faster floating point support)

• RISC OS

• Slackware ARM

• QtonPi (Linux distribution based on the Qt framework)

Operating Sy"ems


Creating a bootable SDCardMac OS X System Information Tool


Download the compressed image file from http://www.raspberrypi.org/downloads

Un-compress the archive, to get to the image file.

df -h, to determine which drive is used for the SDCard

$ sudo diskutil unmount /dev/disk2s1$ sudo dd bs=1m if=./2012-09-18-wheezy-raspbian.img of=/dev/rdisk2$ sync$ sudo diskutil eject /dev/rdisk2

Creating a bootable SDCard


http://www.raspberrypi.org/downloads

http://www.raspberrypi.org/downloads

Configu#ngRa$berry Pi


Configu#ngRa$berry Pi

• sudo raspi-config

• Expand the disk image from 2GB all the way ...

• Re-boot

• sudo raspi-config

• Configure Local

• Configure Keyboard Layout

• Configure TimeZone

• Change Password

• Enable SSH


Ra$berryPi LXDE


Ra$berryPi

$ cat /etc/network/interfaces

auto loiface lo inet loopbackiface eth0 inet dhcp

allow-hotplug wlan0iface wlan0 inet manualwpa-roam /etc/wpa_supplicant/wpa_supplicant.confiface default inet dhcp

$ sudo nano /etc/wpa_supplicant/wpa_supplicant.conf..network={

ssid=”SSID”psk=”******“proto=RSNkey_mgmt=WPA-PSKpairwise=CCMPauth_alg=OPEN

}


Ho"name“raspberrypi”

Change Hostname:

sudo nano /etc/hostname

sudo nano /etc/hosts


Ra$berry PiHeadless Server

Pt.2Copyright © 2012-2013, Wolf Paulus. A Tech Casita Production. All rights reserved.

Steps to make a Raspberry Pi Supercomputerhttp://www.southampton.ac.uk/~sjc/raspberrypi/pi_supercomputer_southampton_web.pdf

MPI: A High Performance Message Passing Libraryhttp://www.open-mpi.org/


http://www.southampton.ac.uk/~sjc/raspberrypi/pi_supercomputer_southampton_web.pdf

http://www.southampton.ac.uk/~sjc/raspberrypi/pi_supercomputer_southampton_web.pdf

http://www.open-mpi.org

http://www.open-mpi.org

apt-get update - updates current list of available packagesapt-get upgrade - updates currently installed packagesapt-get install package-name - installs or upgrades package-name

apt-cache search name - searches the package list for nameapt-get remove package-name - removes packageapt-get --purge remove package-name - removes package and configuration filesapt get autoclean - removes files, needed during upgrade process apt-get autoremove - removes not longer needed dependencies

Advanced Packaging Tool (APT)

Ra$berryPi APT

Sources to retrieve packages from:/etc/apt/sources.list


Install: sudo apt-get install tightvncserverStart: tightvncserverStop: tightvncserver -kill :1

Ra$berryPi VNC Server


Ra$berry PiCamera Server


Ra$berry PiCamera Server

1.) Get the mpeg-streamer source code:svn co https://mjpg-streamer.svn.sourceforge.net/svnroot/mjpg-streamer mjpg-streamer

2.) Installing build dependencies sudo apt-get install libjpeg8-dev imagemagick

3.) make4.) Starting the Camera Stream./mjpg_streamer -i "./input_uvc.so" -o "./output_http.so -w ./www"

<p align="center"> <img src="http://<IP>:8080/?action=stream" width="1280" height="960" /></p>


https://mjpg-streamer.svn.sourceforge.net/svnroot/mjpg-streamer

https://mjpg-streamer.svn.sourceforge.net/svnroot/mjpg-streamer

Ra$berry PiEmbedded Sy"em

Pt.3Copyright © 2012-2013, Wolf Paulus. A Tech Casita Production. All rights reserved.

Arduino UNO : Arduino MEGA : Raspberry Pi


UNO MEGA DUE Pi

Operating Voltage

SRAM

FLASH-Memory

Clock Speed

USB Host

Network

Audio / Video

Current I/O pins

Digital I/O Pins

Analog Input Pins

Price

5 V 5 V 3.3 V 3.3 V

2 KB 8 KB 96 KB 512 MB

32 KB 256 KB 512 KB up to 64 MB

16 MHz 16 MHz 84 MHz 700 MHz

n/a n/a 1 2

n/a n/a n/a 10/100 wired Ethernet RJ45

n/a n/a n/aHDMI, Composite Video,

TRS-audio jack

40 mA 40 mA total 130 mA 2 to 16 mA

14 (6 PWM) 54 (15 PWM) 54 (12 PWM) 17 (1 PWM)

6 1612

2DAC Analog Out 0

$30 $59 $50 $35


MCP3008 8-Channel 10-Bit ADC With SPI Interface

Ra$berryPi wi& ADC


I2C

SPI


I2C connects the same two signal lines to all slaves. I.e. addressing is required and all devices need a unique addressSDA - Serial DataSCL - Serial Clock

Ra$berryPi Inter-IC Bus - I2C


SPI requires four signals: clock (SCLK)master output/slave input (MOSI)master input/slave output (MISO)slave select (SS) or (CS) chip-select

Ra$berryPi Se#al Pe#pheral Interface Bus - SPI


pi@raspberrypi ~ $ cat /etc/modprobe.d/raspi-blacklist.conf# blacklist spi and i2c by default (many users don't need them)blacklist spi-bcm2708blacklist i2c-bcm2708

Loading Kernel Modules:- Edit the raspi-blacklist.conf, so that the i2c module gets enabled.- Add the following lines to /etc/modules

i2c-dev i2c-bcm2708

Reboot, and confirm ls /dev/i2c* shows

/dev/i2c-0 /dev/i2c-1

Installing Dependencies:sudo apt-get install python-smbus i2c-tools

With i2c devices connected, run somthing like this, to discover devices addresses.sudo i2cdetect -y 0

I2C


pi@raspberrypi ~ $ cat /etc/modprobe.d/raspi-blacklist.conf# blacklist spi and i2c by default (many users don't need them)blacklist spi-bcm2708blacklist i2c-bcm2708

Loading Kernel Modules:Edit the raspi-blacklist.conf, so that the spi module gets loaded, Reboot, and confirm with lsmod that ‘spidev’ and ‘spi_bcm2708’ are now loaded and ls /dev/spi* shows two spi devices: /dev/spidev0.0 and /dev/spidev0.1

Installing Dependencies:sudo apt-get install python-dev git-core

Install Python bindings for Linux SPI access through spidev:cd ~git clone git://github.com/doceme/py-spidevcd py-spidev/sudo python setup.py install

... which creates /usr/local/lib/python2.7/dist-packages/spidev.so

SPI


IN =[0000 0001][1CNL ----][---- ----]

(8+channel) <<4OUT=[---- ----][---- -XXX][XXXX XXXX] (10bit)

((r[1] & 3) << 8) + r[2] Copyright © 2012-2013, Wolf Paulus. A Tech Casita Production. All rights reserved.

IN =[0000 0001][1CNL ----][---- ----]

(8+channel) <<4OUT=[---- ----][---- -XXX][XXXX XXXX]

r[0] ((r[1] & 3) << 8) + r[2]

r = spi.xfer2( [1, (8+chnnl)<<4, 0] ) return ((r[1] & 3) << 8) + r[2]


1 #!/usr/bin/python 2 import spidev 3 import time 4 5 # Performs SPI transaction, CS will be held active between blocks 6 # Generally, SPI transfer can transport up to 8KBytes 7 def readadc(chnnl): 8 if (chnnl > 7) or (chnnl < 0): 9 return -1 10 r = spi.xfer2( [1, (8+chnnl)<<4, 0] ) 11 return ((r[1] & 3) << 8) + r[2] 12 13 # Sends a String to an 7-Segment LED display, connected via SPI 14 # The maximum speed of the SPI clock input is 250kHz. 15 # SPI mode 0 (CPOL = 0, CPHA = 0); 16 # the clock line should idle low, and data is sampled on the rising edge of the clock. 17 def sendDisplay(s) : 18 spi.xfer2([118]) # clear screen 19 ca = list(s) # convert the string into a char array 20 spi.xfer2([ord(ca[0]),ord(ca[1]),ord(ca[2]),ord(ca[3])]) 21 return 22 23 # Simple moving average of the list. Up to length item are included. 24 # The new value is added to the given list while the 1st value might be removed. 25 def movavg(list, length, value): 26 list.append(value) 27 if length < len(list) : 28 del list[0] 29 sum=0 30 for x in list[:] : 31 sum+=x 32 return sum / len(list)


33 34 # Declare Global Variables 35 # 36 spi = spidev.SpiDev() 37 pause = 0.5 38 adc_channel = 0 39 movavg_window = 3 40 l = list() 41 42 # Main Loop 43 # 44 while True: 45 time.sleep(pause) 46 47 spi.open(0,0) # Connects the spi object to /dev/spidev-0.0 48 value = readadc(adc_channel) # Read the current ADC Channel value 49 spi.close() # Done with this SPI channel for now 50 51 ma = movavg(l, movavg_window, value) 52 sa = '%04d' % ma 53 54 print value # Show current sensor value in console 55 56 spi.open(0,1) # Connects the SPI object to /dev/spidev-0.1 57 spi.mode=0 # SPI mode 0 (CPOL = 0, CPHA = 0); 58 spi.max_speed_hz = 250000 # Set SPI clock speed to 250kHz. 59 sendDisplay(sa) # update the display 60 spi.close() # Done with this SPI channel for now


3.3V

Ground SPI

Light Sensor

LED-Display

ADCSPI

CS

CS


Light Sensor

LED-Display

SPI

CSCS

SPIADC


Se#al AccessRa$berry Pi


USB to TTL Serial Cable

$10


http://www.adafruit.com/products/954

http://www.adafruit.com/products/954

USB to Serial$ 20


FTDI Basic Breakout - 3.3V

$ 15


BootingRa$berry Pi


60MB Boot Partition easily accessible from your PC

rootfs and tmpfs


Summary.. what we have learned so far ..

General Purpose Computer

Headless Server

Embedded System


(anks for coming





raspberry pi

Technology

wolf paulus

tech casita production

dependencies copyright

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raspberry pi supercomputerhttp

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