CODEWITHSUNDEEP
craspberry-pisensors
Sunaina Chopra
Sunaina Chopra

Reputation: 89

C code for sensor prints output only once and exits

Im a C noob, Ive this code which is supposed to measure body temperature using IR sensor on raspberry pi. The code is working fine but it doesn't work in loop mode and simply prints the temperature only once and exits. While I want it to run continuously until user presses some interrupt key/killed by user.

//gcc mlx90614.c -o mlx90614 -l bcm2835
#include <stdio.h>
#include <bcm2835.h>
#include <stdlib.h>
#include <fcntl.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <time.h>
#define AVG 1   //averaging samples
 
 
int main(int argc, char **argv)
{
    unsigned char buf[6];
    unsigned char i,reg;
    double temp=0,calc=0, skytemp,atemp;
    bcm2835_init();
    bcm2835_i2c_begin();
    bcm2835_i2c_set_baudrate(25000);
    // set address
    bcm2835_i2c_setSlaveAddress(0x5a);
 
    printf("\ndevice is working!!\n");
 
    calc=0;
    reg=7;
 
    for(i=0;i<AVG;i++)
    {
        bcm2835_i2c_begin();
        bcm2835_i2c_write (&reg, 1);
        bcm2835_i2c_read_register_rs(&reg,&buf[0],3);
        temp = (double) (((buf[1]) << 8) + buf[0]);
        temp = (temp * 0.02)-0.01;
        temp = temp - 273.15;
        calc+=temp;
        sleep(1);
    }
 
    skytemp=calc/AVG;
    calc=0;
    reg=6;
 
    for(i=0;i<AVG;i++){
        bcm2835_i2c_begin();
        bcm2835_i2c_write (&reg, 1);
        bcm2835_i2c_read_register_rs(&reg,&buf[0],3);
        temp = (double) (((buf[1]) << 8) + buf[0]);
        temp = (temp * 0.02)-0.01;
        temp = temp - 273.15;
        calc+=temp;
        sleep(1);
    }
 
    atemp=calc/AVG;
 
    printf("ambient temperature = %04.2f\n", atemp);
    printf("object temperature = %04.2f\n", skytemp);
 
    printf("done\n");
 
    return 0;
}

To compile

gcc mlx90614.c -o mlx90614 -l bcm2835
sudo ./mlx90614

Output

device is working!!
ambient temperature = 30.06
object temperature=31.04
done

Upvotes: 1

Views: 144

Answers (1)

Fiddling Bits
Fiddling Bits

Reputation: 8861

You need an infinite loop. For example:

printf("\ndevice is working!!\n");
while(1)
{
    calc=0;
    reg=7;
    ...
    printf("ambient temperature = %04.2f\n", atemp);
    printf("object temperature = %04.2f\n", skytemp);
}
printf("done\n");

Upvotes: 3

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