4.1.8 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.

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/Schematic_three_one2.png

Experimental Procedures

Step 1: Build the circuit.

../_images/image239.png

Step 2: Change directory.

cd /home/pi/raphael-kit/python/

Step 3: Run.

sudo python3 4.1.8_Welcome.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/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. After modifying the code, you can run it directly to see the effect.

#!/usr/bin/env python3

import RPi.GPIO as GPIO
import time

SERVO_MIN_PULSE = 500
SERVO_MAX_PULSE = 2500

ledPin = 18    # define the ledPin
pirPin = 17    # define the sensorPin
servoPin = 22  # define the servoPin
buzPin = 27    # define the buzzerpin


CL = [0, 131, 147, 165, 175, 196, 211, 248]        # Frequency of Low C notes

CM = [0, 262, 294, 330, 350, 393, 441, 495]        # Frequency of Middle C notes

CH = [0, 525, 589, 661, 700, 786, 882, 990]        # Frequency of High C notes

song = [    CH[5],CH[2],CM[6],CH[2],CH[3],CH[6],CH[3],CH[5],CH[3],CM[6],CH[2]    ]

beat = [    1,1,1,1,1,2,1,1,1,1,1,]


def setup():
    global p
    global Buzz                        # Assign a global variable to replace GPIO.PWM
    GPIO.setmode(GPIO.BCM)       # Numbers GPIOs by physical location
    GPIO.setup(ledPin, GPIO.OUT)   # Set ledPin's mode is output
    GPIO.setup(pirPin, GPIO.IN)    # Set sensorPin's mode is input
    GPIO.setup(servoPin, GPIO.OUT)   # Set servoPin's mode is output
    GPIO.output(servoPin, GPIO.LOW)  # Set servoPin to low
    GPIO.setup(buzPin, GPIO.OUT)    # Set pins' mode is output

    Buzz = GPIO.PWM(buzPin, 440)    # 440 is initial frequency.
    Buzz.start(50)                    # Start Buzzer pin with 50% duty ration

    p = GPIO.PWM(servoPin, 50)     # set Frequece to 50Hz
    p.start(0)                     # Duty Cycle = 0

def map(value, inMin, inMax, outMin, outMax):
    return (outMax - outMin) * (value - inMin) / (inMax - inMin) + outMin


def setAngle(angle):      # make the servo rotate to specific angle (0-180 degrees)
    angle = max(0, min(180, angle))
    pulse_width = map(angle, 0, 180, SERVO_MIN_PULSE, SERVO_MAX_PULSE)
    pwm = map(pulse_width, 0, 20000, 0, 100)
    p.ChangeDutyCycle(pwm)#map the angle to duty cycle and output it

def doorbell():
    for i in range(1, len(song)):        # Play song 1
        Buzz.ChangeFrequency(song[i])    # Change the frequency along the song note
        time.sleep(beat[i] * 0.25)        # delay a note for beat * 0.25s
    time.sleep(1)                        # Wait a second for next song.

def closedoor():
    GPIO.output(ledPin, GPIO.LOW)
    for i in range(180, -1, -1): #make servo rotate from 180 to 0 deg
        setAngle(i)
        time.sleep(0.001)
    time.sleep(1)
def opendoor():
    GPIO.output(ledPin, GPIO.HIGH)
    for i in range(0, 181, 1):   #make servo rotate from 0 to 180 deg
        setAngle(i)     # Write to servo
        time.sleep(0.001)
    time.sleep(1)
    doorbell()
    closedoor()

def loop():
    while True:
        if GPIO.input(pirPin)==GPIO.HIGH:
            opendoor()


def destroy():
    GPIO.cleanup()                     # Release resource
    p.stop()
    Buzz.stop()

if __name__ == '__main__':     # Program start from here
    setup()
    try:
        loop()
    except KeyboardInterrupt:  # When 'Ctrl+C' is pressed, the program destroy() will be  executed.
        destroy()

Code Explanation

def setup():
    global p
    global Buzz                        # Assign a global variable to replace GPIO.PWM
    GPIO.setmode(GPIO.BCM)       # Numbers GPIOs by physical location
    GPIO.setup(ledPin, GPIO.OUT)   # Set ledPin's mode is output
    GPIO.setup(pirPin, GPIO.IN)    # Set sensorPin's mode is input
    GPIO.setup(buzPin, GPIO.OUT)    # Set pins' mode is output
    Buzz = GPIO.PWM(buzPin, 440)    # 440 is initial frequency.
    Buzz.start(50)                    # Start Buzzer pin with 50% duty ration
    GPIO.setup(servoPin, GPIO.OUT)   # Set servoPin's mode is output
    GPIO.output(servoPin, GPIO.LOW)  # Set servoPin to low
    p = GPIO.PWM(servoPin, 50)     # set Frequece to 50Hz
    p.start(0)                     # Duty Cycle = 0

These statements are used to initialize the pins of each component.

def setAngle(angle):      # make the servo rotate to specific angle (0-180 degrees)
    angle = max(0, min(180, angle))
    pulse_width = map(angle, 0, 180, SERVO_MIN_PULSE, SERVO_MAX_PULSE)
    pwm = map(pulse_width, 0, 20000, 0, 100)
    p.ChangeDutyCycle(pwm)#map the angle to duty cycle and output it

Create a function, servowrite to write the angle in the servo that is 0-180.

def doorbell():
    for i in range(1,len(song)): # Play song1
        Buzz.ChangeFrequency(song[i]) # Change the frequency along the song note
        time.sleep(beat[i] * 0.25) # delay a note for beat * 0.25s

Create a function, doorbell to enable the buzzer to play music.

def closedoor():
    GPIO.output(ledPin, GPIO.LOW)
    Buzz.ChangeFrequency(1)
    for i in range(180, -1, -1): #make servo rotate from 180 to 0 deg
        setAngle(i)
        time.sleep(0.001)

Close the door and turn off the indicator light.

def opendoor():
    GPIO.output(ledPin, GPIO.HIGH)
    for i in range(0, 181, 1):   #make servo rotate from 0 to 180 deg
        setAngle(i)     # Write to servo
        time.sleep(0.001)
    doorbell()
    closedoor()

The function, opendoor() consists of several parts: turn on the indicator light, turn the servo (to simulate the action of opening the door), play the doorbell music of the convenience store, and call the function , closedoor() after playing music.

def loop():
while True:
    if GPIO.input(pirPin)==GPIO.HIGH:
        opendoor()

When PIR senses that someone is passing by, it calls the function, opendoor() .

Phenomenon Picture

../_images/image240.jpeg