GPIO Zero

Talk given at the Raspberry Pi Big Birthday Weekend

Transcript

1. GPIO Zero
   Ben Nuttall
   Raspberry Pi Foundation
   UK Charity 1129409
   

   View Slide

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

   View Slide

3. GPIO Pins – General Purpose
   Input/Output
   

   View Slide

4. GPIO Zero: a friendly API for GPIO devices
   from gpiozero import LED
   led = LED(17)
   led.on()
   

   View Slide

5. 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

6. 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

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

   View Slide

8. GPIO Zero supports...
   

   View Slide

9. GPIO Zero Device Hierarchy!
   

   View Slide

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

    View Slide

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

    View Slide

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

    View Slide

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

    View Slide

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

    View Slide

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

    View Slide

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

    View Slide

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

    View Slide

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

    View Slide

19. Source tools
    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)
    

    View Slide

20. 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

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

    View Slide

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

    View Slide

23. pigpio - remote GPIO from Pi or PC
    

    View Slide

24. 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

25. 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

26. Internal devices
    ●
    TimeOfDay
    ●
    PingServer
    ●
    CPUTemperature
    ●
    More coming soon
    ●
    Make your own!
    

    View Slide

27. 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

28. Is the internet working?
    from gpiozero import LED, PingServer
    from gpiozero.tools import negated
    green = LED(17)
    red = LED(18)
    google = PingServer('google.com')
    google.source_delay = 60
    green.source = google.values
    red.source = negated(green.values)
    

    View Slide

29. CPU Temperature
    from gpiozero import LEDBarGraph, CPUTemperature
    cpu = CPUTemperature(min_temp=50, max_temp=90)
    leds = LEDBarGraph(2, 3, 4, 5, 6, 7, 8, pwm=True)
    leds.source = cpu.values
    

    View Slide

30. guizero
    

    View Slide

31. PIXEL x86
    

    View Slide

32. PIXEL x86 – Remote GPIO
    

    View Slide

33. GitHub
    

    View Slide

34. What's coming?
    

    View Slide

35. What's coming?
    ●
    More GPIO devices, more internal devices
    ●
    More protocols (I2C, one wire, etc.)
    ●
    Improved documentation
    ●
    Improved Remote GPIO support including Pi Zero OTG
    ●
    Improved advanced features
    ●
    GUI representation for real and mock pins
    ●
    pinout command line tool
    

    View Slide

36. pinout command line tool
    

    View Slide

37. Read the docs!
    

    View Slide

38. Contributors
    ●
    Core team:
    – Ben Nuttall
    – Dave Jones
    – Andrew Scheller
    ●
    Contributors:
    – Martin O'Hanlon
    – Steve Amor
    – David Glaude
    – Edward Betts
    – Alex Chan
    – Thijs Triemstra
    – Schelto vanDoorn
    – Alex Eames
    – Barry Byford
    – Clare Macrae
    – Tim Golden
    – Phil Howard
    

    View Slide

39. The MagPi #55
    

    View Slide

40. GPIO Zero Book
    

    View Slide

41. GPIO Zero
    Ben Nuttall
    Raspberry Pi Foundation
    UK Charity 1129409
    

    View Slide