door-alarm/demo.py
2025-05-08 12:35:21 +02:00

33 lines
695 B
Python

from machine import Pin
import utime
trigger = Pin(2, Pin.OUT)
echo = Pin(3, Pin.IN)
sound = 340 * 100 # m/s * centi = cm/s
def ultra():
trigger.low()
utime.sleep_us(2)
trigger.high()
utime.sleep_us(10)
trigger.low()
# echo goes high as soon as sound wave is sent
# and returns to low once sound gets back
while echo.value() == 0:
sent_time = utime.ticks_us() # us
while echo.value() == 1:
received_time = utime.ticks_us() # us
delta_time = received_time - sent_time # us
distance = delta_time / 1_000_000 * sound / 2
print("The distance from object is", distance, "cm")
while True:
ultra()
utime.sleep(0.1)