/
ultrasonic.c
49 lines (40 loc) · 1.09 KB
/
ultrasonic.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
//Get readings from ultrasonic sensor
#include "pico/stdlib.h"
#include <stdio.h>
#include "hardware/gpio.h"
#include "hardware/timer.h"
int timeout = 26100;
void setupUltrasonicPins(uint trigPin, uint echoPin)
{
gpio_init(trigPin);
gpio_init(echoPin);
gpio_set_dir(trigPin, GPIO_OUT);
gpio_set_dir(echoPin, GPIO_IN);
}
uint64_t getPulse(uint trigPin, uint echoPin)
{
gpio_put(trigPin, 1);
sleep_us(10);
gpio_put(trigPin, 0);
uint64_t width = 0;
while (gpio_get(echoPin) == 0) tight_loop_contents();
absolute_time_t startTime = get_absolute_time();
while (gpio_get(echoPin) == 1)
{
width++;
sleep_us(1);
if (width > timeout) return 0;
}
absolute_time_t endTime = get_absolute_time();
return absolute_time_diff_us(startTime, endTime);
}
uint64_t getCm(uint trigPin, uint echoPin)
{
uint64_t pulseLength = getPulse(trigPin, echoPin);
return pulseLength / 29 / 2;
}
uint64_t getInch(uint trigPin, uint echoPin)
{
uint64_t pulseLength = getPulse(trigPin, echoPin);
return (long)pulseLength / 74.f / 2.f;
}