Help me about sensor and GSM module

[atomy_kwang]

#include <16F877.h>
#fuses HS,NOLVP,NOWDT,NOPROTECT
#use delay(clock = 20000000)
#use rs232(baud=9600,xmit=pin_c6,rcv=pin_c7)

#byte port_b=6

char phone_num[13]="+xxxxxxxxxxx" ;
char ctrl_z=0x1A ;
char CR = 0x0d ;
char LF = 0x0a ;


void send_sms(void)
{

if(!input(PIN_B4))
{
printf("at+cmgs=\"%s\"\n\r",phone_num);
printf("%c\n\r",CR);
printf("%c\n\r",LF);
printf("Products were sold out in Chatuchak area\n\r");
printf("%c\n\r",CR);
printf("%c\n\r",LF);
printf("%c\n\r",ctrl_z);
printf("%c\n\r",CR);
printf("%c\n\r",LF);

}
port_b=0x00;
}

void blink_led()
{
output_toggle(PIN_B7);
delay_ms(100);
}

void main()
{
set_tris_b(0xF0);
blink_led();
while(true)
{
send_sms();
}
}

i would like to send sms if my sensor can detect a light from led
but i have a problem. When sensor detect the sms were sent all time
but i would like to send it enought 1 time

Please help me
thank you

[Guest]

When you run the program, does the LED stay on, or does it flash once and stay off? I would try using output_toggle, output_high and output_low. You don't have to use set_trisb() then.

If you only want to send one message per light reception, you'd probably be better off connecting the sensor to an external interrupt. In the interrupt service routine, set a flag. in the while(true) loop in main(), poll that flag. If the flag is set, clear it, and send your SMS. Also, you don't need to use the set_trisb() if you use output_toggle and output_low.

[crystal_lattice]

Just as a side note, your CR and LF after the printf containing the message is probably redundant as the \n\r does that for you...