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

Talk given at ATO 2017 in Raleigh, NC

Transcript

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
    

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35. 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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36. 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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37. pigpio - remote GPIO from Pi or PC
    

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38. 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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39. 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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40. 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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41. 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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42. pinout command line tool
    

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43. 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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44. Sense HAT
    

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

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46. 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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47. 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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48. Astro Pi: Your code in space
    astro-pi.org
    

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

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

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51. 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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52. 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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53. 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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54. 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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55. 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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56. Picamera image effects
    

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57. Web Streaming
    github.com/waveform80/pistreaming
    

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58. Picamera + OpenCV
    pyimagesearch.com
    

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59. 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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60. 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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61. 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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62. How you can get involved...
    

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63. 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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64. Raspberry Jam near you?
    raspberrypi.org/jam
    

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

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66. 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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67. CoderDojo
    ●
    Free volunteer-led youth
    clubs for under-18s
    ●
    Informal, lots of variety
    ●
    Resources online
    coderdojo.com
    

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

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