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Physical Computing with Python and Raspberry Pi - All Things Open 2017

Physical Computing with Python and Raspberry Pi - All Things Open 2017

Talk given at ATO 2017 in Raleigh, NC

Ben Nuttall

October 23, 2017
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  1. Physical computing
    with Raspberry Pi
    Ben Nuttall
    Raspberry Pi Foundation
    UK Charity 1129409

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  2. Ben Nuttall

    Raspberry Pi Community Manager

    Based in Cambridge, UK

    Columnist on opensource.com

    @ben_nuttall on Twitter

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  3. Over 10 million Raspberry Pis sold

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  4. Over 15 million Raspberry Pis sold

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  5. Raspberry Pi Foundation

    Educational charity founded in
    2009

    Incorporates:
    – Raspberry Pi Trading Ltd
    – Code Club
    – CoderDojo
    – Raspberry Pi Foundation North
    America

    Trading profits fund education
    programmes
    raspberrypi.org/about

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  6. Our mission
    “Putting the power of digital making into the hands of people all over the world”
    So that people are:

    Capable of understanding and shaping an increasingly digital world

    Able to solve the problems that matter to them, both as makers and
    entrepreneurs

    Equipped for the jobs of the future
    raspberrypi.org/about

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  7. We do this by providing...

    Low-cost, high-performance computers

    Outreach and education programmes

    Free resources and teacher training
    p

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  8. Current models

    Raspberry Pi 3

    64-bit quad-core ARMv8
    @ 1.2GHz

    1GB RAM

    $35

    Raspberry Pi Zero / Zero W

    32-bit single-core ARMv6
    @ 1GHz

    512MB RAM

    $5 / $10
    raspberrypi.org/products

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  9. Raspbian desktop
    raspberrypi.org/downloads

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  10. Raspbian x86
    rpf.io/x86

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  11. GPIO Pins – General Purpose
    Input/Output

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  12. Physical computing

    Flashy lights

    Motors & robots

    Photo & video

    Sensors

    Internet of Things

    Home automation

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  13. GPIO

    3V3, 5V

    GPIO, SPI, I2C, UART

    GPIO = variable 3V3 pinout.xyz

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  14. GPIO components

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  15. Add-on boards / HATs

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  16. GPIO with Scratch

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  17. Python - GPIO Zero
    from gpiozero import LED
    from time import sleep
    led = LED(17)
    while True:
    led.on()
    sleep(1)
    led.off()
    sleep(1)

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  18. Python - GPIO Zero
    from gpiozero import LED
    led = LED(17)
    led.blink()

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  19. GPIO Zero supports...

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  20. GPIO Zero Device Hierarchy!

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  21. Multi-paradigm: procedural
    from gpiozero import LED, Button
    led = LED(17)
    button = Button(4)
    while True:
    if button.is_pressed:
    led.on()
    else:
    led.off()

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  22. Multi-paradigm: event-driven
    from gpiozero import LED, Button
    led = LED(17)
    button = Button(4)
    button.when_pressed = led.on
    button.when_released = led.off

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  23. Multi-paradigm: declarative
    from gpiozero import LED, Button
    led = LED(17)
    button = Button(4)
    led.source = button.values

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  24. .value
    >>> led = PWMLED(17)
    >>> led.value
    0.0
    >>> led.on()
    >>> led.value
    1.0
    >>> led.value = 0

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  25. .value
    >>> led = PWMLED(17)
    >>> pot = MCP3008()
    >>> led.value = pot.value

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  26. .value
    >>> led = PWMLED(17)
    >>> pot = MCP3008()
    >>> led.value = pot.value
    >>> while True:
    ... led.value = pot.value

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  27. Source / Values
    Output Device
    .value
    .values
    .source
    Input Device
    .value
    .values

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  28. Source / Values
    Output Device
    .value
    .values
    .source
    Input Device
    .value
    .values

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  29. Source / Values
    from gpiozero import LED, Button
    led = LED(17)
    button = Button(2)
    led.source = button.values

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  30. Processing values
    Output Device
    .value
    .values
    .source
    Input Device
    .value
    .values
    function

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  31. Source tools
    from gpiozero import Button, LED
    from gpiozero.tools import negated
    led = LED(4)
    button = Button(17)
    led.source = negated(button.values)

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  32. Combining values
    Output Device
    .value
    .values
    .source
    Input Device
    .value
    .values
    Source tool
    Input Device
    .value
    .values

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  33. AND logic gate
    from gpiozero import Button, LED
    from gpiozero.tools import all_values
    button_a = Button(2)
    button_b = Button(3)
    led = LED(17)
    led.source = all_values(button_a.values, button_b.values)

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  34. Energenie tortoise lamp
    from gpiozero import Energenie, TimeOfDay
    from datetime import time
    lamp = Energenie(1)
    daytime = TimeOfDay(time(8), time(20))
    lamp.source = daytime.values

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  35. Supporting multiple pin libraries

    RPi.GPIO

    Implemented in C, current default

    Available in PyPI & apt repository (installed by default in Raspbian)

    RPIO

    Implemented in C, supports hardware PWM, supports Pi 1 only (dead project)

    Available in PyPI

    pigpio

    Python wrapper for C library, supports lots of protocols, runs as daemon, supports remote connections

    Available in PyPI & apt repository (installed by default in Raspbian)

    Native

    Pure Python, limited functionality, experimental

    Included in gpiozero source

    MockPin & MockPWMPin

    Pure Python, used in test suite

    Included in gpiozero source

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  36. pigpio - remote GPIO from Pi or PC

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  37. pigpio - remote GPIO from Pi or PC
    from gpiozero import LED
    from gpiozero.pins.pigpio import PiGPIOFactory
    from signal import pause
    factory = PiGPIOFactory('192.168.0.2')
    led = LED(22, pin_factory=factory)
    led.blink()
    pause()

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  38. pigpio - remote GPIO from Pi or PC
    $ export GPIOZERO_PIN_FACTORY=pigpio
    $ export PIGPIO_ADDR=192.168.0.2
    $ python3 led.py
    from gpiozero import LED
    from signal import pause
    led = LED(22)
    led.blink()
    pause()

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  39. MockPin
    $ GPIOZERO_PIN_FACTORY=mock python3
    >>> from gpiozero import LED
    >>> led = LED(22)
    >>> led.blink()
    >>> led.value
    True
    >>> led.value
    False

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  40. MockPin
    >>> from gpiozero import LED
    >>> led = LED(22)
    >>> button = Button(23)
    >>> led.source = button.values
    >>> led.value
    False
    >>> button.pin.drive_low()
    >>> led.value
    True

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  41. pinout command line tool

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  42. Sense HAT

    Special made for Tim Peake's
    Astro Pi mission

    Sensors, LED display &
    joystick

    Great for science, games and
    creativity

    Works on any Pi model

    Emulators also available
    raspberrypi.org/products/sense-hat

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  43. Sense HAT
    >>> from sense_hat import SenseHat
    >>> sense = SenseHat()
    >>> sense.show_message(“Hello world”)

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  44. Sense HAT
    >>> sense.temperature
    25.0
    >>> sense.humidity
    45.0
    >>> sense.accelerometer
    {'pitch': 0.0, 'roll': 0.0, 'yaw': 0.0}
    >>> sense.gyroscope
    {'pitch': 0.0, 'roll': 0.0, 'yaw': 0.0}
    >>> sense.orientation
    {'pitch': 0.0, 'roll': 0.0, 'yaw': 0.0}

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  45. Sense HAT
    from sense_hat import SenseHat
    sense = SenseHat()
    while True:
    r = 255 * sense.humidity / 100
    sense.clear(r, 0, 0)
    pythonhosted.org/sense-hat

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  46. Astro Pi: Your code in space
    astro-pi.org

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  47. Sense HAT Web Emulator
    trinket.io/sense-hat

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  48. Sense HAT Desktop Emulator
    sense-emu.readthedocs.io

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  49. Picamera

    8 megapixels (v2)
    – v1 was 5mpx

    Visible light & infra-red
    versions available

    1080p30, 720p60 and
    VGA90 video

    Command line interface
    and Python library
    raspberrypi.org/products/camera-module-v2

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  50. Picamera - capture
    from picamera import PiCamera
    from time import sleep
    camera = PiCamera()
    camera.start_preview()
    sleep(3)
    camera.capture('/home/pi/Desktop/image.jpg')
    camera.stop_preview()

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  51. Picamera – record video
    from picamera import PiCamera
    from time import sleep
    camera = PiCamera()
    camera.start_preview()
    camera.start_recording('/home/pi/video.h264')
    sleep(10)
    camera.stop_recording()
    camera.stop_preview()

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  52. Picamera + GPIO push button
    from picamera import PiCamera
    from gpiozero import Button
    camera = PiCamera()
    button = Button(17)
    camera.start_preview()
    button.wait_for_press()
    camera.capture('/home/pi/Desktop/image.jpg')
    camera.stop_preview()

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  53. Picamera image effects
    from picamera import PiCamera
    from time import sleep
    camera = PiCamera()
    camera.start_preview()
    for effect in camera.IMAGE_EFFECTS:
    camera.image_effect = effect
    camera.annotate_text = effect
    sleep(1)
    camera.stop_preview()

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  54. Picamera image effects

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  55. Web Streaming
    github.com/waveform80/pistreaming

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  56. Picamera + OpenCV
    pyimagesearch.com

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  57. Google AIY Projects kit

    Free with The MagPi #57

    Now available to buy

    Google Voice HAT + speaker

    Google assistant

    Write code to process custom voice
    commands
    – “Lights on”
    – “Robot go forward”
    – “Take a picture”
    aiyprojects.withgoogle.com

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  58. Mythic Beasts Pi Cloud

    Raspberry Pi 3 in the cloud a data centre

    NFS filesystem (no SD card)

    SSH into a Pi in minutes
    mythic-beasts.com

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  59. The MagPi

    Community magazine established in
    2012 (as free PDF download)

    Now the official Raspberry Pi
    magazine

    Paper copies on sale in UK/US
    shops and online

    Still a free PDF download

    Occasionally comes with a free
    computer or other giveaway

    Book series (buy or download for
    free)
    raspberrypi.org/magpi

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  60. How you can get involved...

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  61. Raspberry Jam

    Independently organised
    community events

    Family-friendly

    Mix of meetup / conference /
    workshop styles

    Raspberry Jam Guidebook and
    more resources available

    Contact me about setting one up!
    raspberrypi.org/jam

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  62. Raspberry Jam near you?
    raspberrypi.org/jam

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  63. Raspberry Jam big birthday weekend
    rpf.io/bday

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  64. Code Club

    Free volunteer-led after
    school clubs for children
    aged 9-13

    Projects provided using
    Scratch, HTML and Python

    Training and support
    provided for volunteers

    Help translating materials
    codeclubworld.org

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  65. CoderDojo

    Free volunteer-led youth
    clubs for under-18s

    Informal, lots of variety

    Resources online
    coderdojo.com

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  66. Raspberry Pi booth

    Booth #41

    Behind the registration desk

    Come say hi!

    Ask questions

    Tell me about your projects

    Find a Raspberry Jam near
    you – or help set one up

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  67. Physical computing
    with Raspberry Pi
    Ben Nuttall
    Raspberry Pi Foundation
    UK Charity 1129409

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