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4.1.3 Welcome¶

Introduction¶

In this project, we will use PIR to sense the movement of pedestrians, and use servos, LED, buzzer to simulate the work of the sensor door of the convenience store. When the pedestrian appears within the sensing range of the PIR, the indicator light will be on, the door will be opened, and the buzzer will play the opening bell.

Required Components¶

In this project, we need the following components.

../_images/4.1.8_welcome_list.png

It’s definitely convenient to buy a whole kit, here’s the link:

Name

ITEMS IN THIS KIT

LINK

Raphael Kit

337

Raphael Kit

You can also buy them separately from the links below.

COMPONENT INTRODUCTION

PURCHASE LINK

GPIO Extension Board

BUY

Breadboard

BUY

Jumper Wires

BUY

Resistor

BUY

LED

BUY

PIR Motion Sensor Module

-

Servo

BUY

Buzzer

BUY

Transistor

BUY

Schematic Diagram¶

T-Board Name

physical

wiringPi

BCM

GPIO18

Pin 12

1

18

GPIO17

Pin 11

0

17

GPIO27

Pin 13

2

27

GPIO22

Pin 15

3

22
../_images/4.1.8_welcome_schematic.png

Experimental Procedures¶

Step 1: Build the circuit.

../_images/4.1.8_welcome_circuit.png

Step 2: Change directory.

cd ~/raphael-kit/python-pi5

Step 3: Run.

sudo python3 4.1.8_Welcome_zero.py

After the code runs, if the PIR sensor detects someone passing by, the door will automatically open (simulated by the servo), turn on the indicator and play the doorbell music. After the doorbell music plays, the system will automatically close the door and turn off the indicator light, waiting for the next time someone passes by.

There are two potentiometers on the PIR module: one is to adjust sensitivity and the other is to adjust the detection distance. To make the PIR module work better, you You need to turn both of them counterclockwise to the end.

../_images/4.1.8_PIR_TTE.png

Code

Note

You can Modify/Reset/Copy/Run/Stop the code below. But before that, you need to go to source code path like raphael-kit/python-pi5. After modifying the code, you can run it directly to see the effect.

#!/usr/bin/env python3

from gpiozero import LED, MotionSensor, Servo, TonalBuzzer
import time

# GPIO pin setup for LED, motion sensor (PIR), and buzzer
ledPin = LED(6)
pirPin = MotionSensor(21)
buzPin = TonalBuzzer(27)

# Servo motor pulse width correction factor and calculation
myCorrection = 0.45
maxPW = (2.0 + myCorrection) / 1000  # Maximum pulse width
minPW = (1.0 - myCorrection) / 1000  # Minimum pulse width

# Initialize servo with custom pulse widths
servoPin = Servo(25, min_pulse_width=minPW, max_pulse_width=maxPW)

# Musical tune for buzzer, with notes and durations
tune = [('C#4', 0.2), ('D4', 0.2), (None, 0.2),
        ('Eb4', 0.2), ('E4', 0.2), (None, 0.6),
        ('F#4', 0.2), ('G4', 0.2), (None, 0.6),
        ('Eb4', 0.2), ('E4', 0.2), (None, 0.2),
        ('F#4', 0.2), ('G4', 0.2), (None, 0.2),
        ('C4', 0.2), ('B4', 0.2), (None, 0.2),
        ('F#4', 0.2), ('G4', 0.2), (None, 0.2),
        ('B4', 0.2), ('Bb4', 0.5), (None, 0.6),
        ('A4', 0.2), ('G4', 0.2), ('E4', 0.2),
        ('D4', 0.2), ('E4', 0.2)]

def setAngle(angle):
    """
    Move the servo to a specified angle.
    :param angle: Angle in degrees (0-180).
    """
    value = float(angle / 180)  # Convert angle to servo value
    servoPin.value = value      # Set servo position
    time.sleep(0.001)           # Short delay for servo movement

def doorbell():
    """
    Play a musical tune using the buzzer.
    """
    for note, duration in tune:
        buzPin.play(note)       # Play the note
        time.sleep(float(duration))  # Duration of the note
    buzPin.stop()               # Stop buzzer after playing the tune

def closedoor():
    # Turn off LED and move servo to close door
    ledPin.off()
    for i in range(180, -1, -1):
        setAngle(i)             # Move servo from 180 to 0 degrees
        time.sleep(0.001)       # Short delay for smooth movement
    time.sleep(1)               # Wait after closing door

def opendoor():
    # Turn on LED, open door (move servo), play tune, close door
    ledPin.on()
    for i in range(0, 181):
        setAngle(i)             # Move servo from 0 to 180 degrees
        time.sleep(0.001)       # Short delay for smooth movement
    time.sleep(1)               # Wait before playing the tune
    doorbell()                  # Play the doorbell tune
    closedoor()                 # Close the door after the tune

def loop():
    # Main loop to check for motion and operate door
    while True:
        if pirPin.motion_detected:
            opendoor()               # Open door if motion detected
        time.sleep(0.1)              # Short delay in loop

try:
    loop()
except KeyboardInterrupt:
    # Clean up GPIO on user interrupt (e.g., Ctrl+C)
    buzPin.stop()
    ledPin.off()

Code Explanation

  1. The script begins by importing necessary modules. The gpiozero library is used to interface with the LED, motion sensor, servo motor, and tonal buzzer. The time module is for handling timing-related functions.

    #!/usr/bin/env python3
from gpiozero import LED, MotionSensor, Servo, TonalBuzzer
import time

  2. Initializes the LED, PIR motion sensor, and tonal buzzer on their respective GPIO pins.

    # GPIO pin setup for LED, motion sensor (PIR), and buzzer
ledPin = LED(6)
pirPin = MotionSensor(21)
buzPin = TonalBuzzer(27)

  3. Calculates the maximum and minimum pulse widths for the servo motor, incorporating a correction factor for fine-tuning.

    # Servo motor pulse width correction factor and calculation
myCorrection = 0.45
maxPW = (2.0 + myCorrection) / 1000  # Maximum pulse width
minPW = (1.0 - myCorrection) / 1000  # Minimum pulse width

  4. Initializes the servo motor on GPIO pin 25 with the custom pulse widths for accurate positioning.

    # Initialize servo with custom pulse widths
servoPin = Servo(25, min_pulse_width=minPW, max_pulse_width=maxPW)

  5. The tune is defined as a sequence of notes (frequency) and durations (seconds).

    # Musical tune for buzzer, with notes and durations
tune = [('C#4', 0.2), ('D4', 0.2), (None, 0.2),
        ('Eb4', 0.2), ('E4', 0.2), (None, 0.6),
        ('F#4', 0.2), ('G4', 0.2), (None, 0.6),
        ('Eb4', 0.2), ('E4', 0.2), (None, 0.2),
        ('F#4', 0.2), ('G4', 0.2), (None, 0.2),
        ('C4', 0.2), ('B4', 0.2), (None, 0.2),
        ('F#4', 0.2), ('G4', 0.2), (None, 0.2),
        ('B4', 0.2), ('Bb4', 0.5), (None, 0.6),
        ('A4', 0.2), ('G4', 0.2), ('E4', 0.2),
        ('D4', 0.2), ('E4', 0.2)]

  6. Function to move the servo to a specified angle. Converts the angle to a value between 0 and 1 for the servo.

    def setAngle(angle):
    """
    Move the servo to a specified angle.
    :param angle: Angle in degrees (0-180).
    """
    value = float(angle / 180)  # Convert angle to servo value
    servoPin.value = value      # Set servo position
    time.sleep(0.001)           # Short delay for servo movement

  7. Function to play a musical tune using the buzzer. Iterates through the tune list, playing each note for its specified duration.

    def doorbell():
    """
    Play a musical tune using the buzzer.
    """
    for note, duration in tune:
        buzPin.play(note)       # Play the note
        time.sleep(float(duration))  # Duration of the note
    buzPin.stop()               # Stop buzzer after playing the tune

  8. Functions to open and close the door using the servo motor. The opendoor function turns on the LED, opens the door, plays the tune, and then closes the door.

    def closedoor():
    # Turn off LED and move servo to close door
    ledPin.off()
    for i in range(180, -1, -1):
        setAngle(i)             # Move servo from 180 to 0 degrees
        time.sleep(0.001)       # Short delay for smooth movement
    time.sleep(1)               # Wait after closing door

def opendoor():
    # Turn on LED, open door (move servo), play tune, close door
    ledPin.on()
    for i in range(0, 181):
        setAngle(i)             # Move servo from 0 to 180 degrees
        time.sleep(0.001)       # Short delay for smooth movement
    time.sleep(1)               # Wait before playing the tune
    doorbell()                  # Play the doorbell tune
    closedoor()                 # Close the door after the tune

  9. Main loop that constantly checks for motion detection. When motion is detected, it triggers the opendoor function.

    def loop():
    # Main loop to check for motion and operate door
    while True:
        if pirPin.motion_detected:
            opendoor()               # Open door if motion detected
        time.sleep(0.1)              # Short delay in loop

  10. Executes the main loop and ensures that the script can be stopped with a keyboard command (Ctrl+C), turning off the buzzer and LED for a clean exit.

    try:
    loop()
except KeyboardInterrupt:
    # Clean up GPIO on user interrupt (e.g., Ctrl+C)
    buzPin.stop()
    ledPin.off()