Python and Raspberry Pi - FOSDEM 2017

Talk on Python and Raspberry Pi at FOSDEM 2017

Transcript

1. Python and Raspberry Pi
   Ben Nuttall
   Raspberry Pi Foundation
   UK Charity 1129409
   

   View Slide

2. Ben Nuttall
   ●
   Raspberry Pi Community Manager
   ●
   Based in Cambridge, UK
   ●
   Creator of gpiozero python library
   ●
   Columnist on opensource.com
   ●
   github.com/bennuttall
   ●
   twitter.com/ben_nuttall
   ●
   ben@raspberrypi.org
   

   View Slide

3. Over 11 million Raspberry Pis sold
   

   View Slide

4. Raspberry Pi Foundation
   ●
   Educational charity founded
   in 2009
   ●
   Owns trading subsidiary
   Raspberry Pi Trading Ltd
   ●
   Trading profits fund
   educational programmes
   

   View Slide

5. 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
   

   View Slide

6. We do this by providing...
   ●
   Low-cost, high-performance computers
   ●
   Outreach and education programmes
   ●
   Free resources and teacher training
   p
   

   View Slide

7. Current models
   ●
   Raspberry Pi 3
   ●
   64-bit quad-core ARMv8
   @ 1.2GHz
   ●
   1GB RAM
   ●
   $35
   ●
   Raspberry Pi Zero
   ●
   32-bit single-core ARMv6
   @ 1GHz
   ●
   512MB RAM
   ●
   $5
   

   View Slide

8. Raspbian Jessie with PIXEL
   

   View Slide

9. PIXEL x86
   

   View Slide

10. GPIO Pins – General Purpose
    Input/Output
    

    View Slide

11. Physical computing
    ●
    Flashy lights
    ●
    Motors & robots
    ●
    Photo & video
    ●
    Sensors
    ●
    Internet of Things
    ●
    Engaging and empowering
    

    View Slide

12. GPIO
    ●
    3V3, 5V
    ●
    GPIO, SPI, I2C, UART
    ●
    GPIO = variable 3V3
    

    View Slide

13. GPIO components
    

    View Slide

14. Add-on boards / HATs
    

    View Slide

15. Python - RPi.GPIO
    import RPi.GPIO as GPIO
    from time import sleep
    GPIO.setmode(GPIO.BCM)
    GPIO.setwarnings(False)
    GPIO.setup(17, GPIO.OUT)
    while True:
    GPIO.output(17, GPIO.HIGH)
    sleep(1)
    GPIO.output(17, GPIO.LOW)
    sleep(1)
    

    View Slide

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

    View Slide

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

    View Slide

18. 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()
    

    View Slide

19. 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
    

    View Slide

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

    View Slide

21. GPIO Zero supports...
    

    View Slide

22. GPIO Zero Device Hierarchy!
    

    View Slide

23. Supporting multiple back-ends
    ●
    RPi.GPIO
    ●
    Implemented in C, current default
    ●
    RPIO
    ●
    Implemented in C
    ●
    pigpio
    ●
    Python wrapper for C library, runs as daemon, remote pins
    ●
    Native
    ●
    Pure Python, limited functionality, experimental
    ●
    MockPin & MockPWMPin
    ●
    Pure Python, used in test suite
    

    View Slide

24. pigpio - remote GPIO from Pi or PC
    

    View Slide

25. pigpio - remote GPIO from Pi or PC
    from gpiozero import LED
    from gpiozero.pins.pigpiod import PiGPIOPin
    led = LED(PiGPIOPin(22, host='192.168.0.2'))
    led.blink()
    

    View Slide

26. pigpio - remote GPIO from Pi or PC
    $ PIGPIO_ADDR=192.168.0.2 python3 led.py
    from gpiozero import LED
    led = LED(22)
    led.blink()
    

    View Slide

27. Picamera
    ●
    8 megapixels (v2)
    – v1 was 5mpx
    ●
    Visible light & infra-red
    versions available
    ●
    1080p30, 720p60 and
    VGA90 video
    ●
    Command line interface
    and Python library
    

    View Slide

28. 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()
    

    View Slide

29. 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()
    

    View Slide

30. 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()
    

    View Slide

31. 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: %s" % effect
    sleep(5)
    camera.stop_preview()
    

    View Slide

32. Picamera image effects
    

    View Slide

33. Web Streaming
    

    View Slide

34. Energenie
    

    View Slide

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
    

    View Slide

36. 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
    

    View Slide

37. Sense HAT
    

    View Slide

38. Sense HAT
    >>> from sense_hat import SenseHat
    >>> sense = SenseHat()
    >>> sense.show_message(“Hello world”)
    >>> sense.temperature
    >>> sense.humidity
    >>> sense.accelerometer
    >>> sense.gyroscope
    >>> sense.orientation
    

    View Slide

39. Sense HAT
    from sense_hat import SenseHat
    sense = SenseHat()
    while True:
    r = 255 * sense.humidity / 100
    sense.clear(r, 0, 0)
    

    View Slide

40. Astro Pi: Your code in space
    

    View Slide

41. Sense HAT Web Emulator
    

    View Slide

42. Sense HAT Desktop Emulator
    

    View Slide

43. Read the docs!
    ●
    gpiozero.readthedocs.io
    ●
    picamera.readthedocs.io
    ●
    pythonhosted.org/sense-hat
    

    View Slide

44. How you can get involved...
    

    View Slide

45. Python libraries
    ●
    Contribute to:
    – gpiozero
    – picamera
    – sense hat
    – more!
    ●
    Help maintainers upgrade modules to Python 3
    ●
    Create your own Python libraries for Raspberry Pi things
    

    View Slide

46. 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
    ●
    Book series (also available for free)
    ●
    raspberrypi.org/magpi
    

    View Slide

47. Raspberry Jam
    ●
    Independently organised
    community events
    ●
    Family-friendly
    ●
    Mix of meetup / conference /
    workshop styles
    ●
    Contact me about setting one
    up!
    ●
    raspberrypi.org/jam
    

    View Slide

48. Code Club
    ●
    Free volunteer-led after
    school clubs for children
    ●
    Projects provided using
    Scratch, HTML and Python
    ●
    Training and support provided
    for volunteers
    ●
    Help translating materials
    ●
    codeclubworld.org
    

    View Slide

49. Python and Raspberry Pi
    Ben Nuttall
    Raspberry Pi Foundation
    UK Charity 1129409
    

    View Slide