mirror of https://github.com/joan2937/pigpio
52 lines
929 B
C
52 lines
929 B
C
#include <stdio.h>
|
|
|
|
#include <pigpio.h>
|
|
|
|
/*
|
|
OH3144E or equivalent Hall effect sensor
|
|
|
|
Pin 1 - 5V
|
|
Pin 2 - Ground
|
|
Pin 3 - gpio (here P1-8, gpio 14, TXD is used)
|
|
|
|
The internal gpio pull-up is enabled so that the sensor
|
|
normally reads high. It reads low when a magnet is close.
|
|
|
|
gcc -o hall hall.c -lpigpio -lrt -lpthread
|
|
sudo ./hall
|
|
*/
|
|
|
|
#define HALL 14
|
|
|
|
void alert(int gpio, int level, uint32_t tick)
|
|
{
|
|
static uint32_t lastTick=0;
|
|
|
|
if (lastTick) printf("%d %.2f\n", level, (float)(tick-lastTick)/1000000.0);
|
|
else printf("%d 0.00\n", level);
|
|
|
|
lastTick = tick;
|
|
}
|
|
|
|
int main(int argc, char *argv[])
|
|
{
|
|
int secs=60;
|
|
|
|
if (argc>1) secs = atoi(argv[1]); /* program run seconds */
|
|
|
|
if ((secs<1) || (secs>3600)) secs = 3600;
|
|
|
|
if (gpioInitialise()<0) return 1;
|
|
|
|
gpioSetMode(HALL, PI_INPUT);
|
|
|
|
gpioSetPullUpDown(HALL, PI_PUD_UP);
|
|
|
|
gpioSetAlertFunc(HALL, alert);
|
|
|
|
sleep(secs);
|
|
|
|
gpioTerminate();
|
|
}
|
|
|