Distance_Proximity_sensor

# Found on seeed studio's wiki and changed it a bit...
# By Seth

import sys
from time import sleep
from pathlib import Path
import os

usleep = lambda x: sleep(x / 1000000.0)

UltraOne = Path('/sys/class/gpio/gpio60/direction')
UltraTwo = Path('/sys/class/gpio/gpio60/value')

_TIMEOUT1 = 1000
_TIMEOUT2 = 10000

class GroveUltrasonicRanger(object):
    def __init__(self):
        self.write_text('low')

    def _get_distance(self):
        self.self = self
        self.write_text('low')
        usleep(2)
        self.write_text('high')
        usleep(10)
        self.write_text('low')

        self.write_text('in') = UltraTwo

        t0 = time.time()
        count = 0
        while count < _TIMEOUT1:
            if self.UltraTwo.read():
                break
            count += 1
        if count >= _TIMEOUT1:
            return None

        t1 = time.time()
        count = 0
        while count < _TIMEOUT2:
            if not self.UltraTwo.read():
                break
            count += 1
        if count >= _TIMEOUT2:
            return None

        t2 = time.time()

        dt = int((t1 - t0) * 1000000)
        if dt > 530:
            return None

        distance = ((t2 - t1) * 1000000 / 29 / 2)    # cm

        return distance

    def get_distance(self):
        while True:
            dist = self._get_distance()
            if dist:
                return dist

Grove = GroveUltrasonicRanger

def main():
    if len(sys.argv) < 2:
        print('Usage: {} pin_number'.format(sys.argv[0]))
        sys.exit(1)

    sonar = GroveUltrasonicRanger(int(sys.argv[1]))

    print('Detecting distance...')
    while True:
        print('{} cm'.format(sonar.get_distance()))
        sleep(2)

if __name__ == '__main__':
    main()