from machine import Pin
import time

soundVelocity=340
distance=0

class SR04(object):
    def __init__(self, trig: int=13, echo: int=14):
        self._trigPin = Pin(trig,Pin.OUT,0)
        self._echoPin = Pin(echo,Pin.IN,0)

    def distanceCM(self):
        self._trigPin.value(1)
        time.sleep_us(10)
        self._trigPin.value(0)    
        while(self._echoPin.value()==0):
            pass
        pingStart=time.ticks_us()
        while(self._echoPin.value()==1):
            pass
        pingStop=time.ticks_us()
        pingTime=time.ticks_diff(pingStop,pingStart)
        distance=pingTime*soundVelocity//2//10000
        return distance
    
    def distanceMM(self):
        self._trigPin.value(1)
        time.sleep_us(10)
        self._trigPin.value(0)    
        while(self._echoPin.value()==0):
            pass
        pingStart=time.ticks_us()
        while(self._echoPin.value()==1):
            pass
        pingStop=time.ticks_us()
        pingTime=time.ticks_diff(pingStop,pingStart)
        distance=pingTime*soundVelocity//2//1000
        return distance
    
    def distance(self):
        self._trigPin.value(1)
        time.sleep_us(10)
        self._trigPin.value(0)    
        while(self._echoPin.value()==0):
            pass
        pingStart=time.ticks_us()
        while(self._echoPin.value()==1):
            pass
        pingStop=time.ticks_us()
        pingTime=time.ticks_diff(pingStop,pingStart)
        distance=pingTime*soundVelocity/2/10000
        return distance