"SmartStick — An Ultrasonic Blind Stick Using Raspberry Pi P

from machine import Pin, time_pulse_us
import utime

# ── Pin Setup ──────────────────────────────────────
TRIG = Pin(0, Pin.OUT)   # Ultrasonic Trigger → GP0
ECHO = Pin(1, Pin.IN)    # Ultrasonic Echo   → GP1
BUZZ = Pin(15, Pin.OUT)  # Buzzer Positive   → GP15

# ── Distance Thresholds (in cm) ────────────────────
DANGER_DIST  = 30   # Very close  → fast beep
WARNING_DIST = 80   # Medium close → slow beep

# ── Get Distance Function ──────────────────────────
def get_distance():
    TRIG.low()
    utime.sleep_us(2)
    TRIG.high()
    utime.sleep_us(10)
    TRIG.low()
    duration = time_pulse_us(ECHO, 1, 30000)
    if duration < 0:
        return None
    distance = (duration * 0.0343) / 2
    return round(distance, 2)

# ── Buzzer Beep Function ───────────────────────────
def beep(on_time, off_time):
    BUZZ.high()
    utime.sleep_ms(on_time)
    BUZZ.low()
    utime.sleep_ms(off_time)

# ── Main Loop ──────────────────────────────────────
print("Blind Stick Started...")

while True:
    dist = get_distance()
    if dist is None:
        print("No object detected")
        BUZZ.low()
        utime.sleep_ms(200)
    else:
        print("Distance:", dist, "cm")
        if dist <= DANGER_DIST:
            beep(on_time=100, off_time=100)
        elif dist <= WARNING_DIST:
            beep(on_time=200, off_time=500)
        else:
            BUZZ.low()
            utime.sleep_ms(200)