삼성 아틱 조도센서를 이용한 LED 밝기 조정하기

 #include <stdio.h>

#include <stdlib.h>

#include <stdbool.h>

#define HIGH            1

#define LOW 0

#define ANALOG_PIN          0 // A0

#define PWM_PIN 0

#define PERIOD 1000000

bool pwmPin(int pin, int period, int duty_cycle, int enable){

    FILE * fd;

    char fName[128];

    if(( fd = fopen("/sys/class/pwm/pwmchip0/export", "w")) == NULL) {

        printf("Error: unable to export pin\n");

        return false;

    }

    fprintf(fd, "%d\n", pin);

    fclose(fd);

    sprintf(fName, "/sys/class/pwm/pwmchip0/pwm%d/period", pin);

    if((fd = fopen(fName, "w")) == NULL) {

        printf("Error: can't open pin period\n");

        return false;

    }

    fprintf(fd, "%d\n", period);

    fclose(fd);

    sprintf(fName, "/sys/class/pwm/pwmchip0/pwm%d/duty_cycle", pin);

    if((fd = fopen(fName, "w")) == NULL) {

        printf("Error: can't open pin duty_cycle\n");

        return false;

    }

    fprintf(fd, "%d\n", duty_cycle);

    fclose(fd);

    sprintf(fName, "/sys/class/pwm/pwmchip0/pwm%d/enable", pin);

    if((fd = fopen(fName, "w")) == NULL) {

        printf("Error: can't open pin enable\n");

        return false;

    }

    if(enable == HIGH) {

        fprintf(fd, "1\n");

    }

    else {

        fprintf(fd, "0\n");

    }

    fclose(fd);

    return true;

}

int analogRead(int pin) {

           FILE * fd;

           char fName[64];

           char val[8];

           // open value file

           sprintf(fName, "/sys/devices/12c0000.adc/iio:device0/in_voltage%d_raw", pin);

           if((fd = fopen(fName, "r")) == NULL) {

                       printf("Error: can't open analog voltage value\n");  

                       return 0;

           }         

           fgets(val, 8, fd);

           fclose(fd);

           return atoi(val);

}

int Con_duty(int duty) {

           pwmPin(PWM_PIN, PERIOD, duty, 1);

}

int main(void)

{

    long SenVal = 0;

    while(1)

    {

        SenVal = analogRead(ANALOG_PIN);

        printf("val : %d\n", SenVal);

                       if (SenVal > 500) Con_duty(100000); // LED ON

                       else if (SenVal <= 500) Con_duty(0); // LED OFF

                       sleep(1);

    }

           return 0;

}

 from time import sleep

OUTPUT = 'out'

INPUT = 'in'

HIGH = 1

LOW = 0

def export(pin):

    try:

        exp = open('/sys/class/gpio/export','wb',0)

        exp.write(str(pin))

        print('Registion Successful: pin%d' %pin)

    except IOError as e:

        print('Error: %d - %s' %(e.errno,e.strerror))

def unexport(pin):

    try:

        uexp = open('/sys/class/gpio/unexport','wb',0)

        uexp.write(str(pin))

        print('Unregistion Successful: pin%d' %pin)

        uexp.close()

    except IOError as e:

        print('Error: %d - %s' %(e.errno,e.strerror))

def pinMode(pin, mode):

    try:

        direction = open('/sys/class/gpio/gpio%d/direction' %pin,'wb',0)

        direction.write('out' if mode == OUTPUT else 'in')

        direction.close()

    except IOError as e:

        print('Error: %d - %s' %(e.errno,e.strerror))

def digitalWrite(pin,value):

    try:

        val = open('/sys/class/gpio/gpio%d/value' %pin,'wb',0)

        val.write(str(value))

        val.close()

    except IOError as e:

        print('Error: %d - %s' %(e.errno,e.strerror))

def analogRead(pin):

    filePath = '/sys/devices/platform/c0000000.soc/c0053000.adc/iio:device0/in_voltage%d_raw' %pin

    try:

        file = open(filePath,"rb",0)

        value = file.read()

        file.close()

        return int(value)

    except IOError as e:

        print('Error: %d - %s' %(e.errno, e.strerror))

        return 0

LEDpin = 128

LightSensor = 0

export(LEDpin)

pinMode(LEDpin,OUTPUT)

try:

while True:

raw = analogRead(LightSensor)

volt = raw * 1.8/4095

print("Raw value: %d" %raw)

print("Voltage: %0.2f" %volt)

if raw <= 1024:

digitalWrite(LEDpin, HIGH)

else:

digitalWrite(LEDpin, LOW)

sleep(0.5)

except KeyboardInterrupt:

unexport(LEDpin)

print("Stop!!!")