ultrasonic.py

from machine import Pin, PWM
import time

class Ultrasonic:
    
    def __init__(self, echoPinNum, triggerPinNum):
        self.echoPin = Pin(echoPinNum, Pin.IN, 0)
        self.trigPulse = PWM(Pin(triggerPinNum, Pin.OUT), freq=10, duty=1)
        self.startEcho = 0
        self.endEcho = 0
        self.distance = 0
        self.lastMeasure = 0
        self.soundVelocity=340
        self.echoPin.irq(trigger=Pin.IRQ_RISING | Pin.IRQ_FALLING, handler=self.measure)

    def measure(self, pin):
        if pin.value():
            self.startEcho = time.ticks_us()
        else:
            self.endEcho = time.ticks_us()
            self.distance = self.calculateCM(self.startEcho, self.endEcho)
            self.lastMeasure = self.endEcho

    def calculateCM(self, start, stop):
        ticks=time.ticks_diff(stop,start)
        return int(ticks*self.soundVelocity//2//10000)