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