Physical computing for beginners with GPIO Zero

Presentation given at Bett 2016 introducing educators to physical computing with Raspberry Pi and GPIO Zero

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
   ●
   @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()
    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. GPIO Zero
    ●
    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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27. GPIO Zero
    ●
    Pre-installed in Raspbian Jessie
    ●
    Available with apt:
    – sudo apt-get install python3-gpiozero
    – sudo apt-get install python-gpiozero
    

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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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