from machine import Pin, I2C, time_pulse_us
from time import sleep_us, sleep
import ssd1306
import machine

i2c_dev = I2C(0, scl=Pin(5), sda=Pin(4), freq=200000)

display = ssd1306.SSD1306_I2C(128, 64, i2c_dev)
display.text('Hello, World!', 0, 0, 1)

button = machine.Pin(12, machine.Pin.IN, machine.Pin.PULL_UP)

display.show()

ECHO_PIN = 22
TRIGGER_PIN = 26

trigger = Pin(TRIGGER_PIN, Pin.OUT)
echo = Pin(ECHO_PIN, Pin.IN)

CM = True

def detect_dist():
    global pulse_duration

    trigger.low()
    sleep_us(2)
    trigger.high()
    sleep_us(10)
    trigger.low()

    pulse_duration = time_pulse_us(echo, 1, 30000)

    if CM:
        pulse_duration = pulse_duration / 58
    else:
        pulse_duration = pulse_duration / 148


while True:
    detect_dist()

    display.fill(0)

    display.text("Distance: ", 0, 0, 1)
    display.text(str(pulse_duration) + (" CM" if CM else " INCH"), 0, 20, 1)

    sleep(0.1)
    display.show()

    if not button.value():
        CM = not CM