#L8a - Program control sensor cu ultrasunete de tip
# HC-SR04 
# Conexiuni:
# Vcc  - 5V
# trig - pin 24 (GP18)
# echo - pin 25 (GP19)
# GND  - GND
# Semnalul echo trabuie adus la nivel de max 3,3V, necesita
# divizor rezitiv.

import machine
import utime

trig=machine.Pin(18, machine.Pin.OUT)
echo=machine.Pin(19, machine.Pin.IN, machine.Pin.PULL_UP)
led=machine.Pin(25, machine.Pin.OUT)

trig.value(0)      # initializare
led.value(0)


while 1:                   # bucla infinita
	trig.value(1)      # start trig
	utime.sleep(0.00001) # 10 microsecunde
	trig.value(0)        # porneste emisie US


	while echo()==0:
		start_t=utime.ticks_us() # in 1 iese cu ultima valoare
	while echo()==1:
		stop_t=utime.ticks_us() # in 0 iese cu ultima valoare
	durata=stop_t - start_t         # durata dus-intors ultrasunete
        dist= durata*342/2/10000      # in cm
	
        print("%.2f" % dist, "cm")    # afisare distanta
        if dist < 10 :
		led.value(1) # aprind led
        else:
		led.value(0) # sting led
	utime.sleep(0.4)            # secunde