PIR Motion sensor - GPIO library

  • Light an LED when a MotionSensor detects motion:


    • GPIO gpio pir-motion-sensor 
     
from gpiozero import MotionSensor, LED
from signal import pause

pir = MotionSensor(4)
led = LED(16)

pir.when_motion = led.on
pir.when_no_motion = led.off

pause()

Light sensor - GPIO library

  • GPIO gpio light sensor


  • Have a LightSensor detect light and dark: 


    •  
from gpiozero import LightSensor

sensor = LightSensor(18)

while True:
    sensor.wait_for_light()
    print("It's light! :)")
    sensor.wait_for_dark()
    print("It's dark :(")

  • Run a function when the light changes: 


    •  
from gpiozero import LightSensor, LED
from signal import pause

sensor = LightSensor(18)
led = LED(16)

sensor.when_dark = led.on
sensor.when_light = led.off

pause()

  • Or make a PWMLED change brightness according to the detected light level: 


    •  
    
from gpiozero import LightSensor, PWMLED
from signal import pause

sensor = LightSensor(18)
led = PWMLED(16)

led.source = sensor

pause()

Distance sensor - GPIO library

  • GPIO gpio distance sensor


  • Note In the diagram above, the wires leading from the sensor to the breadboard can be omitted; simply plug the sensor directly into the breadboard facing the edge (unfortunately this is difficult to illustrate in the diagram without the sensor’s diagram obscuring most of the breadboard!)


  • Have a DistanceSensor detect the distance to the nearest object: 


    •  
from gpiozero import DistanceSensor
from time import sleep

sensor = DistanceSensor(23, 24)

while True:
    print('Distance to nearest object is', sensor.distance, 'm')
    sleep(1)

  • Run a function when something gets near the sensor: 


    •  
from gpiozero import DistanceSensor, LED
from signal import pause

sensor = DistanceSensor(23, 24, max_distance=1, threshold_distance=0.2)
led = LED(16)

sensor.when_in_range = led.on
sensor.when_out_of_range = led.off

pause()

Servo- GPIO library

  • Control a servo between its minimum, mid-point and maximum positions in sequence: 


    •  
from gpiozero import Servo
from time import sleep

servo = Servo(17)

while True:
    servo.min()
    sleep(2)
    servo.mid()
    sleep(2)
    servo.max()
    sleep(2)

  • Use a button to control the servo between its minimum and maximum positions: 


    •  
from gpiozero import Servo, Button

servo = Servo(17)
btn = Button(14)

while True:
    servo.min()
    btn.wait_for_press()
    servo.max()
    btn.wait_for_press()

  • Automate the servo to continuously slowly sweep: 


    •    
from gpiozero import Servo
from gpiozero.tools import sin_values

servo = Servo(17)

servo.source = sin_values()
servo.source_delay = 0.1

  • Use AngularServo so you can specify an angle: 


    •     
from gpiozero import AngularServo
from time import sleep

servo = AngularServo(17, min_angle=-90, max_angle=90)

while True:
    servo.angle = -90
    sleep(2)
    servo.angle = -45
    sleep(2)
    servo.angle = 0
    sleep(2)
    servo.angle = 45
    sleep(2)
    servo.angle = 90
    sleep(2)

Motors - GPIO library

  • GPIO gpio motor


  • Spin a Motor around forwards and backwards: 


    •  
from gpiozero import Motor
from time import sleep

motor = Motor(forward=4, backward=14)

while True:
    motor.forward()
    sleep(5)
    motor.backward()
    sleep(5)

Robot - GPIO library

  • GPIO gpio robot


  • Make a Robot drive around in (roughly) a square: 


    •  
from gpiozero import Robot
from time import sleep

robot = Robot(left=(4, 14), right=(17, 18))

for i in range(4):
    robot.forward()
    sleep(10)
    robot.right()
    sleep(1)

  • Make a robot with a distance sensor that runs away when things get within 20cm of it: 


    •  
    
from gpiozero import Robot, DistanceSensor
from signal import pause

sensor = DistanceSensor(23, 24, max_distance=1, threshold_distance=0.2)
robot = Robot(left=(4, 14), right=(17, 18))

sensor.when_in_range = robot.backward
sensor.when_out_of_range = robot.stop
pause()