Physical computing with GPIO Zero - oggcamp

Presentation given at oggcamp 2015 on the new GPIO Zero Python library

Transcript

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

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2. Ben Nuttall
   ●
   Education Developer Advocate
   at the Raspberry Pi Foundation
   – Software & project development
   – Learning resources & teacher
   training
   – Outreach
   ●
   Hobbyist turned employee
   ●
   Based in Cambridge (but from
   the North)
   ●
   @ben_nuttall on Twitter
   

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3. Python – RPi.GPIO
   import RPi.GPIO as GPIO
   from time import sleep
   GPIO.setmode(GPIO.BCM)
   GPIO.setwarnings(False)
   led = 17
   GPIO.setup(led, GPIO.OUT)
   while True:
   GPIO.output(led, True)
   sleep(1)
   GPIO.output(led, False)
   sleep(1)
   

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4. 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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5. LED
   from gpiozero import LED
   from time import sleep
   led = LED(17)
   led.on() # on
   led.off() # off
   led.toggle() # on­>off or off­>on
   led.blink() # flash on/off continuously
   

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6. LED + Button
   from gpiozero import LED, Button
   led = LED(17)
   button = Button(3)
   button.when_pressed = led.on
   button.when_released = led.off
   

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7. Source + Values
   from gpiozero import LED, Button
   led = LED(17)
   button = Button(3)
   led.source = button.values
   

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8. LED - PWM
   from gpiozero import PWMLED
   from time import sleep
   led = PWMLED(17)
   led.on() # on
   led.off() # off
   led.value = 0.5 # half brightness
   

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9. Motion sensor
   from gpiozero import LED, MotionSensor
   led = LED(2)
   sensor = MotionSensor(3)
   sensor.when_motion = led.on
   sensor.when_no_motion = led.off
   

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10. Light sensor
    from gpiozero import LED, LightSensor
    led = LED(2)
    sensor = LightSensor(3)
    while True:
    sensor.wait_for_light()
    print("It's light!")
    sensor.wait_for_dark()
    print("It's dark")
    

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11. Traffic Lights
    from gpiozero import TrafficLights
    lights = TrafficLights(9, 10, 11)
    lights.on() # all on
    lights.off() # all off
    lights.red.on() # red on
    lights.toggle() # swap state of all lights
    

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12. Traffic Lights sequence
    lights.green.on()
    lights.amber.off()
    lights.red.off()
    while True:
    sleep(10)
    lights.green.off()
    lights.amber.on()
    sleep(1)
    lights.amber.off()
    lights.red.on()
    sleep(10)
    lights.amber.on()
    sleep(1)
    lights.green.on()
    lights.amber.off()
    lights.red.off()
    

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13. TrafficHat
    from gpiozero import TrafficHat
    th = TrafficHat()
    th.lights.red.on()
    th.lights.amber.on()
    th.button.when_pressed = th.on
    th.button.when_released = th.off
    

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14. TrafficHat - PWM
    from gpiozero import TrafficHat
    th = TrafficHat(pwm=True)
    th.lights.red.value = 0.2
    th.lights.amber.value = 0.4
    th.lights.green.value = 0.8
    

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15. Push button stop motion
    from gpiozero import Button
    from picamera import PiCamera
    button = Button(4)
    with PiCamera() as camera:
    camera.start_preview()
    frame = 1
    while True:
    button.wait_for_press()
    camera.capture('/home/pi/frame%03d.jpg' % frame)
    frame += 1
    

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16. Full colour LED
    from gpiozero import RGBLED
    led = RGBLED(2, 3, 4)
    led.red.on() # full red
    led.color = (1, 0, 1) # purple
    led.blue = 0.3 # dim the blue value to 0.3
    # now (1, 0, 0.3)
    

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17. Motor
    from gpiozero import Motor
    from time import sleep
    motor = Motor(forward=17, backward=18)
    while True:
    motor.forward()
    sleep(5)
    motor.backward()
    sleep(5)
    

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18. Robot
    from gpiozero import Robot
    from time import sleep
    robot = Robot(left=(17, 18), right=(22, 23))
    while True:
    robot.forward()
    sleep(10)
    robot.left()
    sleep(1)
    

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19. Button controlled Robot
    from gpiozero import RyanteckRobot, Button
    robot = RyanteckRobot()
    left = Button(26)
    right = Button(16)
    fw = Button(21)
    bw = Button(20)
    fw.when_pressed = robot.forward
    fw.when_released = robot.stop
    left.when_pressed = robot.left
    left.when_released = robot.stop
    right.when_pressed = robot.right
    right.when_released = robot.stop
    bw.when_pressed = robot.backward
    bw.when_released = robot.stop
    

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20. Analogue - potentiometers
    from gpiozero import MCP3008
    pot = MCP3008()
    while True:
    print(pot.value)
    

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21. Dial up the brightness!
    from gpiozero import PWMLED, MCP3008
    led = PWMLED(2)
    pot = MCP3008()
    while True:
    led.value = pot.value
    

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22. Dial up the brightness!
    from gpiozero import PWMLED, MCP3008
    led = PWMLED(2)
    pot = MCP3008()
    led.source = pot.values
    

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23. Analogue - potentiometers
    from gpiozero import RGBLED, MCP3008
    led = RGBLED(red=2, green=3, blue=4)
    red_pot = MCP3008(channel=0)
    green_pot = MCP3008(channel=1)
    blue_pot = MCP3008(channel=2)
    while True:
    led.red = red_pot.value
    led.green = green_pot.value
    led.blue = blue_pot.value
    

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24. Analogue - potentiometers
    from gpiozero import RGBLED, MCP3008
    led = RGBLED(red=2, green=3, blue=4)
    red_pot = MCP3008(channel=0)
    green_pot = MCP3008(channel=1)
    blue_pot = MCP3008(channel=2)
    led.red.source = red_pot.values
    led.green.source = green_pot.values
    led.blue.source = blue_pot.values
    

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25. GPIO Music Box
    from gpiozero import Button
    import pygame.mixer
    from pygame.mixer import Sound
    pygame.mixer.init()
    def play(pin):
    sound = sound_pins[pin]
    print("playing note from pin %s" % pin)
    sound.play()
    sound_pins = {
    2: Sound("samples/drum_tom_mid_hard.wav"),
    3: Sound("samples/drum_cymbal_open.wav"),
    }
    buttons = [Button(pin) for pin in sound_pins]
    for button in buttons:
    sound = sound_pins[button.pin]
    button.when_pressed = sound.play
    

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26. Analogue - potentiometers
    from gpiozero import PWMLED, MCP3008
    led = PWMLED(2)
    pot = MCP3008()
    led.source = pot.values
    

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27. GPIO Zero - beta
    ●
    www.pythonhosted.org/gpiozero
    – Installation instructions
    – Documentation
    – Examples
    ●
    GitHub Issues
    – Suggestions
    – Feedback
    ●
    Contact me
    – ben@raspberrypi.org
    – @ben_nuttall on Twitter
    ●
    #gpiozero on Twitter
    

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28. CamJam EduKit
    ●
    £5 starter kit (kit 1)
    ●
    £7 sensors kit (kit 2)
    ●
    £17 robotics kit (kit 3)
    ●
    Free worksheets
    ●
    Very reusable
    

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29. The MagPi
    

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30. The MagPi
    

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31. Physical computing with GPIO Zero
    Ben Nuttall
    Raspberry Pi Foundation
    UK Charity 1129409
    

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