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Physical computing with GPIO Zero
Ben Nuttall
Raspberry Pi Foundation
UK Charity 1129409
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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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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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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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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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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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Source + Values
from gpiozero import LED, Button
led = LED(17)
button = Button(3)
led.source = button.values
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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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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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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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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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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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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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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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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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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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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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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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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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Analogue - potentiometers
from gpiozero import MCP3008
pot = MCP3008()
while True:
print(pot.value)
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Dial up the brightness!
from gpiozero import PWMLED, MCP3008
led = PWMLED(2)
pot = MCP3008()
while True:
led.value = pot.value
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Dial up the brightness!
from gpiozero import PWMLED, MCP3008
led = PWMLED(2)
pot = MCP3008()
led.source = pot.values
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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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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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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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GPIO Zero - beta
●
www.pythonhosted.org/gpiozero
– Installation instructions
– Documentation
– Examples
●
GitHub Issues
– Suggestions
– Feedback
●
Contact me
– [email protected]
– @ben_nuttall on Twitter
●
#gpiozero on Twitter
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CamJam EduKit
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£5 starter kit (kit 1)
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£7 sensors kit (kit 2)
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£17 robotics kit (kit 3)
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Free worksheets
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Very reusable
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Raspberry Pi blog
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The MagPi
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The MagPi
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The MagPi
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Physical computing with GPIO Zero
Ben Nuttall
Raspberry Pi Foundation
UK Charity 1129409