Help with Serial port

[DaleNguyenVN]

I've tried to send SMS from GSM Sim900A using Arduino Mega to my mobile phone when the gas sensor triggered but the received message was blank.
There are some other tasks (Light Sensor, PIR Sensor, ...)but they work normally. I'm just in trouble with Sim900A task
Here below is my entire code.
Hope to receive your support.
Thanks a lot.

#include <Arduino_FreeRTOS.h>
#include <semphr.h>
#include <Servo.h>
#include <SPI.h>
#include <RFID.h>

#define SS_PIN 53
#define RST_PIN 8
#define Servo_Pin 45


int LightSensorPin = 6;
int LightSensorLED = 7;
int PIRSensorPin = 5;
int PIRSensorLED = 3;
int gasPin = A0;

SemaphoreHandle_t xSerialSemaphore;
SemaphoreHandle_t xSerial2Semaphore;

Servo myservo;
RFID rfid(SS_PIN, RST_PIN);

unsigned long time1 =0;

//Voice confirguration
int led = 34;

int gas_thres = 300;
int pinbuzzer = 40;

unsigned char reading_card[5];
unsigned char member1[5] = {124, 166, 19, 50, 251};
unsigned char member2[5] = {64, 185, 152, 124, 29};

unsigned char i, j;
int val = 0; 


//------------ Task Assignment -------/

void TaskDoor( void *pvParameters);
void TaskLightSensor(void *pvParameters);
void TaskPIRSensor(void *pvParameters);
void TaskGasSensor(void *pvParameters);
void TaskSerial(void *pvParameters);

//-------------End Task Assignment ------//

void exitdoor()
{
  myservo.write(150);
}

void setup() 
{
  pinMode(2, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(2), exitdoor, LOW);
  pinMode(pinbuzzer, OUTPUT);
  digitalWrite(pinbuzzer, HIGH);
  Serial.begin(9600);
  Serial1.begin(9600);
  Serial2.begin(9600);

  while (!Serial and !Serial2)
  {
    ;
  }
  
 //--------Semaphore Declaration------------//// 
 if ( xSerialSemaphore == NULL )  // Check to confirm that the Serial Semaphore has not already been created.
  {
    xSerialSemaphore = xSemaphoreCreateMutex();  // Create a mutex semaphore we will use to manage the Serial Port
    if ( ( xSerialSemaphore ) != NULL )
      xSemaphoreGive( ( xSerialSemaphore ) );  // Make the Serial Port available for use, by "Giving" the Semaphore.
  }

  if ( xSerial2Semaphore == NULL )  // Check to confirm that the Serial Semaphore has not already been created.
  {
    xSerial2Semaphore = xSemaphoreCreateMutex();  // Create a mutex semaphore we will use to manage the Serial Port 2
    if ( ( xSerial2Semaphore ) != NULL )
      xSemaphoreGive( ( xSerial2Semaphore ) );  // Make the Serial Port available for use, by "Giving" the Semaphore.
  }
   
  


//===============Task Create =================//

//---Task Door----//

xTaskCreate(
  TaskDoor
  , (const portCHAR *) "Door" 
  , 128 //RAM for program >= 64byte
  , NULL
  , 2 //Priority level
  , NULL );

//---Task Light Sensor ---//

  xTaskCreate(
    TaskLightSensor
    , (const portCHAR *) "LightSensor"
    , 128 
    , NULL
    , 2
    , NULL);

    //---Task PIR Sensor---//
    
  xTaskCreate(
    TaskPIRSensor
    , (const portCHAR *) "PIRSensor"
    , 128 
    , NULL
    , 2
    , NULL);

  xTaskCreate(
    TaskGasSensor
    , (const portCHAR *) "GasSensor"
    , 1028
    , NULL
    , 2
    , NULL);

  xTaskCreate(
    TaskSerial
    , (const portCHAR *) "TaskSerial"
    , 512
    , NULL
    , 2
    , NULL);
    
  }//end Creating Tasks

//-----Delay function--------//
void Delay(float delayTime){
        unsigned long endTime = millis() + delayTime;
        while(millis() < endTime)
        {
        
          while(millis() < endTime){};  
        }
    }


//-----Play tune---------
void Buzzer(float playtime){
        unsigned long endtime = millis() + playtime;
        while(millis() < endtime)
        {
          digitalWrite(pinbuzzer, LOW);
          Delay(200);
          digitalWrite(pinbuzzer, HIGH);
          Delay(200);
        }
    }
//==============LOOP===============//

void loop() {
//Nothing in loop
}

//--------------Task Detail-----------//

void TaskDoor(void *pvParameters)
{
  (void) pvParameters;
  myservo.attach(Servo_Pin);
  SPI.begin();
  rfid.init();
  myservo.write(30);
  pinMode(28, INPUT);
  
  for(;;)
  {
  if (rfid.isCard()) 
       {
            if (rfid.readCardSerial()) // Detect card
            {    
                for (i = 0; i < 5; i++) 
                {
                    reading_card[i] = rfid.serNum[i]; //Store the scanned card value to reading_card
                }
                //Serial.println();
                //verification
                
                for (i = 0; i < 5; i++) {
                    //Compare each element of the card to the stored value
                    if (reading_card[i] != member1[i]) 
                    {
                        break;
                    }
                }
                for (j = 0; j < 5; j++) {
                    if (reading_card[i] != member2[i]) {
                        break;
                    }
                }
                if ((i == 5)||(j == 5)) 
                {
                    myservo.write(150); // open door
                    time1 = millis();
                
                    Delay(2000);
                    myservo.write(30);         //close door           
                }
                else
                {
                  Buzzer(1000);             
                }                         
            }
            rfid.halt();   
        }        
  }
}

void TaskLightSensor(void *pvParameters __attribute__((unused)))
{
  (void) pvParameters;
    pinMode(led, OUTPUT);
    pinMode(LightSensorLED, OUTPUT);
    pinMode(LightSensorPin, INPUT);
  for(;;)
  {
  
      int LightSensorval = digitalRead(LightSensorPin);
      digitalWrite(LightSensorLED, LightSensorval);
  }
}

void TaskPIRSensor(void *pvParameters)
{
  (void) pvParameters;

    pinMode(PIRSensorLED, OUTPUT);
    pinMode(PIRSensorPin, INPUT);
  for(;;)
  {
    int PIRSensorval = digitalRead(PIRSensorPin);
    digitalWrite(PIRSensorLED, PIRSensorval);
    Delay(100);    
  }
}

void TaskGasSensor(void *pvParameters __attribute__((unused)))
{
  (void) pvParameters;
  
  pinMode(gasPin, INPUT);
  for(;;)
  {
    
    int gas = analogRead(gasPin);
     
    if (gas > gas_thres)
    {
      Buzzer(2000);
    {
      {
             sendSMS("Gas detected");
      }
    }
      Delay(100);
    
    }
  }
}

void TaskSerial(void *pvParameters __attribute__((unused)))
{
  (void) pvParameters;
  char fire;
  for(;;)
  {

      if ( xSemaphoreTake( xSerial2Semaphore, ( TickType_t ) 5 ) == pdTRUE )
    { 
             if(Serial2.available() > 0)
              {
                fire = Serial2.read();
              }
             xSemaphoreGive( xSerial2Semaphore ); // Now free or "Give" the Serial Port for others.
    }
    
    if (fire == 'H')
    {
      Buzzer(2000);
             sendSMS("High Temp");
      }
      Delay(100);
  }
}

//------Send SMS---------
void sendSMS(String message)
{
  Serial1.println("AT");
  vTaskDelay(7);
  // AT command to set SIM900 to SMS mode
  Serial1.println("AT+CMGF=1"); 
  vTaskDelay(7);

  // change to your sim900's your phone number
  Serial1.println("AT+CMGS=\"+84931770634\"\r"); 
  delay(100);
  // Send the SMS
  Serial1.println(message); 
  delay(100);

  // End AT command with a ^Z, ASCII code 26
  Serial1.println((char)26); 
  Serial1.println();
  // Give module time to send SMS
  vTaskDelay(7);  
}

[feilipu]

I'd suggest that the first thing to do is to remove the various delay(), and Delay() functions references, and just stick to using the vTaskDelay() function for creating a delay.

Delay functions that hammer millis(); seem to cause substantial issues with the serial port response, no matter what else might be working.

You might be ok writing a delay function specifically for tone generation, but otherwise steer clear of non vTaskDelay() implementation.