UltrasonicDistance Sensor

#include "pico/stdlib.h"
#include "hardware/gpio.h"

int timeout = 26100; // max µs to wait

// Fire TRIG pulse, measure ECHO width
uint64_t getPulse(uint trigPin, uint echoPin) {
    gpio_put(trigPin, 1);
    sleep_us(10);        // ≥10µs HIGH pulse
    gpio_put(trigPin, 0);

    uint width = 0;

    // Wait for ECHO to go HIGH
    while (gpio_get(echoPin) == 0)
        tight_loop_contents();

    // Count µs while ECHO stays HIGH
    while (gpio_get(echoPin) == 1) {
        width++;
        sleep_us(1);
        if (width > timeout) return 0;
    }
    return width;
}

// Convert pulse width → centimeters
int getCm(uint trig, uint echo) {
    uint64_t pulse = getPulse(trig, echo);
    return pulse / 29 / 2;
}

// Convert pulse width → inches
int getInch(uint trig, uint echo) {
    uint64_t pulse = getPulse(trig, echo);
    return (long)pulse / 74.f / 2.f;
}

int main() {
    stdio_init_all();
    uint trigPin = 2, echoPin = 3;

    gpio_init(trigPin); gpio_set_dir(trigPin, GPIO_OUT);
    gpio_init(echoPin); gpio_set_dir(echoPin, GPIO_IN);

    while (true) {
        int d = getCm(trigPin, echoPin);
        printf("\nDistance: %d cm", d);
        sleep_us(10000);
    }
}