Simple Social Distance Detector

// davisde //

Video Overview

WHAT YOU NEED

PARTS LIST

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Steps

STEP 1 – Wiring

First we need to wire up all the components to the Pi Pico. You can download the Fritzing diagram, or just use the diagram image to the left. Here’s how it will look:

HC-SR04
VCC > Pin 40
GND > GND
Trig > GP3
Echo > GP2

SSD1306
VCC > Pin 36
GND > GND
SDA > GP0
SCL > GP1

Buzzer
GND > GND
Power > GP13

STEP 2 – Code

I’m using the Thonny python editor.

# IMPORT NECESSARY DEPENDENCIES
# THE SSD1306 DEPENDENCY IS AN EXTERNAL DEPENDENCY
from machine import Pin, I2C, Timer, PWM
from ssd1306 import SSD1306_I2C
import utime


# INITIALIZE DISPLAY
i2c = I2C(0,sda=Pin(0),scl=Pin(1),freq=40000)
oled = SSD1306_I2C(128,64,i2c)

# INITIALIZE HC-SR04 SENSOR
trigger = Pin(3, Pin.OUT)
echo = Pin(2, Pin.IN)

# INITITALIZE BUZZER #
buzzer = PWM(Pin(13))
# set audio frequency
buzzer.freq(500)
# set audio volume from 0 to 1000
buzzer.duty_u16(1000)

# INITIALIZE VARIABLES #
target_distance = 2 #meters

# CREATE A FUNCTION TO CHECK FOR DISTANCE #
def sensor():
    # turn off trigger, and wait for 2 microseconds
    trigger.low()
    utime.sleep_us(2)
    # turn on trigger, and wait for 5 microseconds
    trigger.high()
    utime.sleep_us(5)
    # turn off trigger
    trigger.low()
    # count time it takes to receive an echo
    while echo.value() == 0:
        signaloff = utime.ticks_us()
    while echo.value() == 1:
        signalon = utime.ticks_us()
    timepassed = signalon - signaloff
    #convert the time to measurements
    #measurement in cm
    #distance = (timepassed * 0.0343) / 2
    #measurement in m
    distance = (timepassed * 0.000343) / 2
    #measurement in feet
      #distance = (timepassed * 1125) / 2
    return distance

# ADD MAIN LOOP TO 'TRY' STATEMENT IN CASE OF ERRORS #
try:
    # CREATE MAIN LOOP #
    while True:
        # WIPE DISPLAY SCREEN #
        oled.fill(0)
        # GET RESULT FROM SENSOR #
        result = sensor()
        if result < target_distance:
            buzzer.duty_u16(1000)
            oled.text("TOO CLOSE!",0,20)
        else:
            buzzer.duty_u16(0)
        oled.text("Distance:",0,0)
        oled.text(str(result) + " m",0,10)
        oled.text("",0,20)
        oled.show()
        utime.sleep(1)            
except KeyboardInterrupt:
    pass

 

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