GSM module SIM 900 Problem to send SMS (FIXED VERSION)

Projects Programming
16

Hello, it's been a while.

Good new: I finally managed to modify the program by activiting the SIM card with the hardware trigger and it worked ! I managed to send the SMS.

Here is the code I used !

#include <SoftwareSerial.h>

//Create software serial object to communicate with SIM900
SoftwareSerial mySerial(7, 8); //SIM900 Tx & Rx is connected to Arduino #7 & #8

void setup()
{
  //SIM900power();
  //Begin serial communication with Arduino and Arduino IDE (Serial Monitor)
  Serial.begin(9600);
  
  //Begin serial communication with Arduino and SIM900
  mySerial.begin(9600);

  Serial.println("Initializing..."); 
  delay(1000);

  mySerial.println("AT"); //Handshaking with SIM900
  updateSerial();

  mySerial.println("AT+CMGF=1"); // Configuring TEXT mode
  updateSerial();
  mySerial.println("AT+CMGS=\"+33686920417\"");//change ZZ with country code and xxxxxxxxxxx with phone number to sms
  updateSerial();
  mySerial.print("YO"); //text content
  updateSerial();
  mySerial.write(26);
}

void loop()
{
}

void updateSerial()
{
  delay(500);
  while (Serial.available()) 
  {
    mySerial.write(Serial.read());//Forward what Serial received to Software Serial Port
  }
  while(mySerial.available()) 
  {
    Serial.write(mySerial.read());//Forward what Software Serial received to Serial Port
  }
}

//void SIM900power()
//{
  //pinMode(9, OUTPUT); 
  //digitalWrite(9,LOW);
  //delay(1000);
  //digitalWrite(9,HIGH);
  //delay(2000);
  //digitalWrite(9,LOW);
  //delay(3000);
//}

I simply removed the SIM900power () function which would permits the program to activate the SIM card without needing to push the button.

However, I need to activate by software and without using the button, and I noticed that we needed to solder the R13 SMD jumper on the shield (look at the part named Software trigger in the tutorial).

The GSM module shield I used was originally sent by my internship tutor alongside with a lot of other stuff for my project. I took a picture about the R13 emplacement.

![image|317x393](upload://7EU0ei8BwgBc34dQHXqI6OcvlqU.jpeg

We could see a component here, but I don't know if it is well soldered as aked on the tuto or not.
If it's not, what kind of tools would you advise me to do it ?

Also, for the TX RX jumpers, should I move them for using D1 and D0 instead of D7 and D8 ?

image

I used D7 and D8 for activating the SIM card with the button, and it worked well.

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