counting-people.py

# Libraries
import RPi.GPIO as GPIO
from time import sleep, time

GPIO.setwarnings(False)
 
# GPIO Mode (BOARD / BCM)
GPIO.setmode(GPIO.BOARD)

# LED pins
LED_1 = 24
LED_2 = 26
LED_3 = 32

GPIO.setup(LED_1, GPIO.OUT, initial=GPIO.LOW)
GPIO.setup(LED_2, GPIO.OUT, initial=GPIO.LOW)
GPIO.setup(LED_3, GPIO.OUT, initial=GPIO.LOW)

# set GPIO Pins
GPIO_TRIGGER = 12
GPIO_ECHO = 18
 
# set GPIO direction (IN / OUT)
GPIO.setup(GPIO_TRIGGER, GPIO.OUT)
GPIO.setup(GPIO_ECHO, GPIO.IN)


def distance():
    # set Trigger to HIGH
    GPIO.output(GPIO_TRIGGER, True)
 
    # set Trigger after 0.01ms to LOW
    sleep(0.00001)
    GPIO.output(GPIO_TRIGGER, False)
 
    StartTime = time()
    StopTime = time()
 
    # save StartTime
    while GPIO.input(GPIO_ECHO) == 0:
        StartTime = time()
 
    # save time of arrival
    while GPIO.input(GPIO_ECHO) == 1:
        StopTime = time()
 
    # time difference between start and arrival
    TimeElapsed = StopTime - StartTime
    # multiply with the sonic speed (34300 cm/s)
    # and divide by 2, because there and back
    distance = (TimeElapsed * 34300) / 2
 
    return distance


def led_on(pin):
    GPIO.output(pin, GPIO.HIGH)

def led_off():
    GPIO.output(LED_1, GPIO.LOW)
    GPIO.output(LED_2, GPIO.LOW)
    GPIO.output(LED_3, GPIO.LOW)

# Have to be atleast 20cm away from the sensor
# Anything more than that is completely ignored
minimumProximity = 20

if __name__ == '__main__':
  wasBlocking = False
  personCount = 0

    try:
        while True:
            dist = int(distance())

            if wasBlocking == True:
              if dist > minimumProximity:
                # Person stopped blocking sensor
                wasBlocking = False
                personCount += 1
                led_off()
              else:
                # The sensor is still being blocked
            else:
              if dist < minimumProximity:
                # Person started blocking sensor
                wasBlocking = True
                led_on(LED_1)
              else:
                # Nothing in front of the sensor
                led_off()

            print("Person count: %s" % personCount)
            sleep(0.5)
 
      # Reset by pressing CTRL + C
    except KeyboardInterrupt:
        print("Stopped by user...")
        GPIO.cleanup()