Library

•

Toma Laura

Published June 22, 2020

Social distancing sensor

By using the sensor, when you get too close it will warn you by making a sound and changing the led color.

IntermediateShowcase (no instructions)3 hours712

Things used in this project

Hardware components

RGB Diffused Common Cathode

Ultrasonic Sensor - HC-SR04 (Generic)

Buzzer

Breadboard (generic)

Male/Female Jumper Wires

Male/Male Jumper Wires

Resistor 1k ohm

Through Hole Resistor, 150 ohm

General Purpose Transistor NPN

1N4007 – High Voltage, High Current Rated Diode

Software apps and online services

Raspberry Pi Raspbian

Story

Nowadays, because of the pandemic, we will have to be more careful when it comes to the distance between us and other people. By using our project, you will always be warned when someone is too close to you.

Howit works:

The device is set to react when an object/person is "close" (< 75 cm) or "too close" (< 25 cm). The "close" mode activates the buzzer and turns the RGB led into the blue light. The "too close" mode, makes the buzzer sounds more disturbing and turns the RGB led into the red light. While the distance between the persons is bigger than 75 centimetres, the light will be green and the buzzer will play a song, for letting you know that there is no one too close to you.

video demonstration

Library:

For our project we've used the pigpio library which is installed in the following steps:

first download and install the latest version:

wget https://github.com/joan2937/pigpio/archive/master.zipunzip master.zipcd pigpio-mastermakesudo make install

before you run the code, you need to start the pigpio daemon

sudo pigpiod

for running the code use the following command :

python3 project.py

Code

Code

import time
import pigpio
import RPi.GPIO as GPIO
import array

a3 = 220
e5 = 659
d5 = 587
a4 = 440
f3 = 175
f5 = 698
d3 = 147
g3 = 196
c5 = 523
b4 = 494
g4 = 392
e3 = 165
a5 = 880
e4 = 330

dl1 = 0.7
dl2 = 0.2
dl3 = 0.3
dl4 = 0.1
dl5 = 0.4

sequence_1_notes = array.array('i', [a4, c5, a4, a4, d5, a4, g4, a4, e5, a4, a4, f5, e5, c5, a4, e5, a5, a4, g4, g4, e4, b4, a4])
sequence_1_delays = array.array('f', [dl2, dl2, dl2, dl3, dl3, dl3, dl2, dl2, dl2, dl2, dl3, dl3, dl2, dl2, dl2, dl2, dl3, dl3, dl2, dl3, dl3, dl4, dl5])

pi = pigpio.pi()

buzzer = 12

pi.set_mode(buzzer, pigpio.OUTPUT)
GPIO.setmode(GPIO.BOARD)

trig = 18
echo = 16
redled = 11
greenled = 13
blueled = 15

GPIO.setup(trig, GPIO.OUT)
GPIO.setup(echo, GPIO.IN)

GPIO.setup(redled, GPIO.OUT)
GPIO.setup(greenled, GPIO.OUT)
GPIO.setup(blueled, GPIO.OUT)

def song():
        for i in range(0,23):
                pi.hardware_PWM(buzzer, sequence_1_notes[i], 50000)
                time.sleep(sequence_1_delays[i])
                pi.hardware_PWM(buzzer, 0, 0)
                time.sleep(dl4)

                GPIO.output(greenled, GPIO.HIGH)
                time.sleep(0.01)
                GPIO.output(greenled, GPIO.LOW)
                time.sleep(0.01)

def calculate_distance():
        GPIO.output(trig, GPIO.HIGH)

        time.sleep(0.00001)
        GPIO.output(trig, GPIO.LOW)

        start = time.time()
        stop = time.time()

        while GPIO.input(echo) == 0:
                start = time.time()

        while GPIO.input(echo) == 1:
                stop = time.time()

        duration = stop - start

        distance = 34300/2 * duration
        if distance < 0.5 and distance > 400:
                return 0
        else:
                return distance

try:

        while True:
                if calculate_distance() < 25:
                        pi.hardware_PWM(buzzer, 500, 500000)
                        time.sleep(0.05)

                        pi.hardware_PWM(buzzer, 0, 0)
                        time.sleep(0.035)

                        GPIO.output(redled, GPIO.HIGH)
                        time.sleep(0.035)

                        GPIO.output(redled, GPIO.LOW)
                        time.sleep(0.025)
                elif calculate_distance() > 25 and calculate_distance() < 75:
                        pi.hardware_PWM(buzzer, 300, 400000)
                        time.sleep(0.05)

                        GPIO.output(blueled, GPIO.HIGH)
                        time.sleep(0.3)

                        GPIO.output(blueled, GPIO.LOW)
                        time.sleep(0.2)

                        pi.hardware_PWM(buzzer, 0, 0)
                        time.sleep(0.03)

                elif calculate_distance() > 75:
                        GPIO.output(greenled, GPIO.HIGH)
                        time.sleep(0.5)

                        GPIO.output(greenled, GPIO.LOW)
                        time.sleep(0.2)
                        song()
except KeyboardInterrupt:
        pass

pi.write(buzzer, 0)
pi.stop()

GPIO.cleanup()

Credits

Mihaila Andreea

1 project • 0 followers

Toma Laura

1 project • 0 followers

Social distancing sensor