Introduction to Raspberry Pi and GPIO

Raspberry Pi A Slice For Education http://www.raspberrypi.org

Who Am I ?My Name is Kris Findlay. Also known in the community as Azmodie.I have been using the Open Source Linux operating system for over 10 years. IT Manager for Animation Company (makers of oscar nominated The Illusionist 2010) I am also the Webmaster for The Software Society and The UK AdhesionsSociety (Charity) which are both implemented, hosted and developed with opensource software. ( currently Django, apache, nginx, mysql )Email address : azmodie@gmail.com or kris.findlay@gmail.comIdenti.ca/Twitter : azmodieGoogle Plus : http://gplus.to/azmodieLinkedIn : Kris Findlay

Agenda• A Little history • More device specifics• What a Raspberry Pi can do for you ? • Other Emerging Embeded Platforms• Development Options• Possible live/video demo. • Questions

A Little history The Raspberry Pi was created by the Raspberry Pi Foundation toinspire a new generation of children to become programmers.Foundation trustee Eben Upton, a lecturer at Cambridge at the time,saw that the skillset of applicants to CS courses had been steadilydecreasing for a number of years. This is mostly due to the way thateducation has been geared more towards using office applications andless on understanding the hardware.The Debian images available have lots of tools for both kids and adultsalike. so almost any age 4-50+ can enjoy learning about programmingand electronics.

More device specificsModel A256Mb RAM1 x USBno EthernetModel B256Mb RAM2 x USB1 x EthernetBoth models have a700MHz Armv6 (Arm11)Quad-Core Graphics chip Diagram of Model B

What a RaspberryPi can do for you• Xbmc @ Full 1080p HD• Linux desktop - just add keyboard and mouse.• Linux low powered server (fileserver etc..)• Attach webcam and monitoring software• Interface with electronics from leds, solenoids,switches,mosfets etc..• Almost anything else you can imagine

Other Emerging Embeded Platforms• VIA APC is powered by a VIA WonderMedia 8750 800 MHz ARM11 processor, 512MB of DDR3 memory, and 2GB of flash storage. The chip supports 1080p HD video playback, H.264 video encoding, and OpenGL ES 2.0 graphics.• Android Mk802 A10 AllWinner Mini Computer The little computer looks like a portable storage device, but it has a 1.5 GHz Allwiner A10 processor, 512MB(1Gb spotted) of RAM, and 4GB of storage. It ships with Google Android 4.0 software• Beagle Board (1GHZ ARM 7) and Beagle bone (720MHz ARM 7) also PandaBoard (all ~$80-$180)

Development Options• Python (Quick2wire),C(WiringPi), Bash, Basic, etc..• Scratch Geared to students and non-developers• Various Other Linux environments including Aros (Linux based port), Arch, Debian, Gentoo etc..• Many open-source libraries being ported to arm.• Cross-compiler tool-chains available. (both soft and hard float)

ScratchThe MIT program Scratch is designed to provide an accessible way forkids to learn about coding.The programs interface makes it easy to build and change software bydragging and dropping commands and changing variable valuesthrough simple menus.The version installed on the Pi comes loaded with a simple car-racinggame. Users can add and remove commands from the game, thenpress play and immediately see the effect of those changes - forinstance, tweaking how cars handle or adjusting the animation for carcrashes.

Scratch Example

Quick2Wire (Python GPIO)quick2wire have released a python api to safely access the gpio pinsfrom user land. eg. anyone in the gpio group. as well as allowing cleanimport and export of pins.Here’s the code that drives an LED:from quick2wire.gpio import Pinfrom time import sleepout_pin = Pin(12, Pin.Out) for i in range(0, 10): out_pin.value = 1 sleep(1) out_pin.value = 0 sleep(1)out_pin.unexport()http://quick2wire.com/https://github.com/quick2wire/quick2wire-python-apihttps://github.com/quick2wire/quick2wire-gpio-admin

My Raspberry Pi DemoMy demo focuses on input and output from python script through the gpio pins tosome simple electronics components.This simple demo takes input from a switchwhich illuminates a red led to confirm it waspressed.using the quick2wire api for python.when the switch is pressed a counter isincreased by 1 until it reaches 16 at whichpoint it will reset counter to 0.the corospoding value of counter at any onetime is then convirted to binary value anddisplayed on the 4 green and yellow leds.eg. counter = 3 bin outpit = 0011 led pin = 0011

My Raspberry Pi Demo

My Raspberry Pi Demo#!/usr/bin/python3import time # outputs binary reprisentation to 4 ledsimport string # that matches count.from quick2wire.gpio import Pin binvalue = bin(i)[2:].zfill(4) out_pin4.value = binvalue[-1]# import pins for output out_pin3.value = binvalue[-2]out_pin1 = Pin(11, Pin.Out) out_pin2.value = binvalue[-3]out_pin2 = Pin(13, Pin.Out) out_pin1.value = binvalue[-4]out_pin3 = Pin(15, Pin.Out) time.sleep(.2)out_pin4 = Pin(16, Pin.Out) # trap ctrl+c to cleanly unexport pins# import pins for input except KeyboardInterrupt:in_pin = Pin(7, Pin.In) out_pin1.unexport() out_pin2.unexport()# init count out_pin3.unexport()count = 0 out_pin4.unexport() in_pin.unexport()try:while True: # get input value of button mybutton = in_pin.value if mybutton == False: count = count + 1 # reset at 16 if count == 16: count = 0 rpi-count.py @ https://github.com/azmodie/rpi-scripts

expEYES ProjectThe expEYES (“experiments for Young Engineers and Scientists”) aims toprovide a low cost platform for experimentation and education in electronics andphysics.The device has 12 bit Analog I/O, Digital I/O,time interval measurements, & other featuresaccessible from Python. It is packaged with anumber of accessories & software which canbe used to perform a large number ofexperiments.For example, the device can be used to studyelectromagnetic induction, the conductivity ofwater, to measure gravity by time of flight,alongside many other applications. It aims toenable anybody to develop new experiments.http://expeyes.in/articles/54/expeyes-meets-raspberry-pi

Links to More Details / ProjectsA coffee machine controlled by Raspberry Pihttp://moccapi.blogspot.co.uk/Solinoid based glockenspielhttp://www.thebox.myzen.co.uk/Raspberry/Buffer_Board.htmlSimple Guide to the RPi GPIO Header and Pinshttp://www.raspberrypi-spy.co.uk/2012/06/simple-guide-to-the-rpi-gpio-header-and-pins/Raspberry Pi – Driving a Relay using GPIOhttp://www.susa.net/wordpress/2012/06/raspberry-pi-relay-using-gpio/Hardware Ladder Gamehttp://www.raspberrypi.org/archives/1488Speach Recognitionhttps://sites.google.com/site/observing/Home/speech-recognition-with-the-raspberry-piIdeas for model railwayshttp://www.raspberrypi.org/phpBB3/viewtopic.php?f=37&t=5993

Contact Details & Any Questions ? Email address : azmodie@gmail.com / kris.findlay@gmail.com Twitter : azmodie Facebook : azmodie LinkedIn : Kris Findlay

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Introduction to Raspberry Pi and GPIO

by Kris Findlay on Aug 26, 2012

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