If loop problem

Projects Programming
1

Hi I'm new to Arduino, i'm using the Arduino UNO.
While programming a bidirectionnal communication with Arduino and my phone (recieving sms and responding with the right answer. I'm having trouble with my loop, which means it's always just the "else " part that respond to the sms and never is the " if" part working..
Could you help me?

#include <DFRobot_sim808.h>
#include <SoftwareSerial.h>


#define PHONE_NUMBER "+33768522026"  
 
//The content of messages sent
#define MESSAGE1  "ceci est du francais"
#define MESSAGE2 "ceci est de l'anglais"

#define MESSAGE_LENGTH 160
char message[MESSAGE_LENGTH];
int messageIndex = 0;

char phone[16];
char datetime[24];

#define PIN_TX    10
#define PIN_RX    11
SoftwareSerial mySerial(PIN_TX,PIN_RX);
DFRobot_SIM808 sim808(&mySerial);

//DFRobot_SIM808 sim808(&Serial);

void setup() {
  mySerial.begin(9600);
  Serial.begin(9600);
  while(!sim808.init()) {
      Serial.print("Sim808 init error\r\n");
      delay(1000);
  }
  delay(3000);  
  Serial.println("Init Success, please send SMS message to me!");
 
 

  //******** define phone number and text **********
   //Serial.print("messageIndex: ");
   //Serial.println(messageIndex);
    while(!sim808.init()) {
      delay(1000);
      Serial.print("Sim808 init error\r\n");
  }  
  Serial.println("Sim808 init success");
  Serial.println("Start to send message ...");
   if (strcmp(message ,"bonjour") )
    {
    sim808.sendSMS(PHONE_NUMBER,MESSAGE1); 
    Serial.println("message1 envoyé");
    }
   else (strcmp(message ,"hello") ) ;
   Serial.println("message2 envoyé");
    {
    sim808.sendSMS(PHONE_NUMBER,MESSAGE2); 
    }
}
  


void loop() {
   //*********** Detecting unread SMS ************************
   
    //Serial.print("messageIndex: ");
    //Serial.println(messageIndex);

   //*********** At least, there is one UNREAD SMS ***********
   if (messageIndex > 0) { 
      sim808.readSMS(messageIndex, message, MESSAGE_LENGTH, phone, datetime);
      Serial.println("Sim808 init success");
      Serial.println("Start to send message ...");
      if (messageIndex == "bonjour") 
        {
       sim808.sendSMS(PHONE_NUMBER,MESSAGE1); 
       }
      else ( messageIndex == "hello") ;
        {
        sim808.sendSMS(PHONE_NUMBER,MESSAGE2); 
        }
      
  //***********In order not to full SIM Memory, is better to delete it**********
      sim808.deleteSMS(messageIndex);
      Serial.print("From number: ");
      Serial.println(phone);  
      Serial.print("Datetime: ");
      Serial.println(datetime);        
      Serial.print("Recieved Message: ");
      Serial.println(message); 
   }
 }
2

‘messageIndex’ is an int, when you compare it to == "…" it will be false. you probably want to compare ‘message’ variable which you cannot compare using == either. use strcmp

1 Like
3

Thank you!

if (strcmp(message ,"bonjour") )

Like this? Because I tried like you said and still the if part is not working..

4

But in the method
bool readSMS (int messageIndex, char * message, int length, char * phone, char * datetime);
messageIndex is an integer number and cannot be "hello" or "bonjour".
Put
Serial.println(messageIndex); right after sim808.readSMS() and you will see what it is equal to.

5

Yes thanks, but in the loop i've replaced it by

message

6

Is it your code?

7

Oh sorry here is the new one:

#include <DFRobot_sim808.h>
#include <SoftwareSerial.h>


#define PHONE_NUMBER "+33768522026"  
 
//The content of messages sent
#define MESSAGE1  "ceci est du francais"
#define MESSAGE2 "ceci est de l'anglais"

#define MESSAGE_LENGTH 160
char message[MESSAGE_LENGTH];
int messageIndex = 0;

char phone[16];
char datetime[24];

#define PIN_TX    10
#define PIN_RX    11
SoftwareSerial mySerial(PIN_TX,PIN_RX);
DFRobot_SIM808 sim808(&mySerial);

//DFRobot_SIM808 sim808(&Serial);

void setup() {
  mySerial.begin(9600);
  Serial.begin(9600);
  while(!sim808.init()) {
      Serial.print("Sim808 init error\r\n");
      delay(1000);
  }
  delay(3000);  
  Serial.println("Init Success, please send SMS message to me!");
 
 

  //******** define phone number and text **********
   //Serial.print("messageIndex: ");
   //Serial.println(messageIndex);
    while(!sim808.init()) {
      delay(1000);
      Serial.print("Sim808 init error\r\n");
  }  
  Serial.println("Sim808 init success");
  Serial.println("Start to send message ...");
   if (strcmp(message ,"bonjour") )
    {
    sim808.sendSMS(PHONE_NUMBER,MESSAGE1); 
    Serial.println("message1 envoyé");
    }
   else (strcmp(message ,"hello") ) ;
   Serial.println("message2 envoyé");
    {
    sim808.sendSMS(PHONE_NUMBER,MESSAGE2); 
    }
}
  


void loop() {
   //*********** Detecting unread SMS ************************
   
    //Serial.print("messageIndex: ");
    //Serial.println(messageIndex);

   //*********** At least, there is one UNREAD SMS ***********
   if (messageIndex > 0) { 
      sim808.readSMS(messageIndex, message, MESSAGE_LENGTH, phone, datetime);
      Serial.println("Sim808 init success");
      Serial.println("Start to send message ...");
      if (strcmp(message ,"bonjour") )
        {
       sim808.sendSMS(PHONE_NUMBER,MESSAGE1); 
       }
      else (strcmp( message,"hello")) ;
        {
        sim808.sendSMS(PHONE_NUMBER,MESSAGE2); 
        }
   }   
  //***********In order not to full SIM Memory, is better to delete it**********
sim808.deleteSMS(messageIndex);
    
 }
8

Well then, print the message to the Serial Monitor and see what it is equal to.
Check its length, see if there is '\ n', '\ r' at the end.

1 Like
9

read documentation on strcmp, this will return false when there is exact match, you need

if (strcmp(message ,"bonjour") == 0)

1 Like
10

Alright, thank you

11

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