serial is print twice?

Question

I have a problem , when send 1 or 0 by Bluetooth module the serial monitor print two time (RECEIVED SMS) . what's the wrong ?

This is my code :

 char BluetoothData = 0 ; 
void setup() {
 // initialize serial communication:
 Serial.begin(9600);
 for (int pin = 1; pin <= 13; pin++)
 {
 pinMode(pin, OUTPUT); // sets the digitals pin as outputs
 digitalWrite(pin, LOW); // sets the digitals pin off defult intial states 
 } 
 Serial.println("ALL LEDs NOW OFF \n "); 
 Serial.println("Please, Enter : ( 1 to Turn on All LEDs ) or ( 0 to Turn off LEDs ) \n");
}
void loop() { 
 // read the sensor:
 if (Serial.available() > 0) {
 BluetoothData = Serial.read();
 Serial.print("*** RECEIVED SMS *** : ==>> ");
 Serial.println(BluetoothData);
 if (BluetoothData == '1'){ 
 for (int Pin = 1; Pin <= 13; Pin++) {
 digitalWrite(Pin, HIGH);
 } 
 Serial.println("ALL LEDs NOW ON");
 }
 // turn all the LEDs off:
 else if (BluetoothData == '0') {
 for (int Pin = 1; Pin <= 13; Pin++) {
 digitalWrite(Pin, LOW);
 }
 Serial.println("ALL LEDs NOW OFF"); 
 }
 }
 delay(100); 
} 

This is photo for serial monitor

enter image description here

• user3629249: Please do not post photos of the output, rather select the text, then copy/paste the text into the question, as indented code
• user3629249: for ease of readability and understanding: 1) please consistently indent the code. Indent after every opening brace '{'. Unindent before every closing brace '}'. Suggest each indent level be 4 spaces.
• user3629249: the posted code does not contain a main() function, not the necessary #include statements. So how are we to reproduce the problem?
• Khalid Abu-Khadija: I cannot understand all the functions and terms of the site. I weak in that, is there a video that explains the matter?

Answer 1

Probably the first time because you received the character '1' or '0'. The second character is probably a '0円' or '\d', an end-of-string or end-of-line character.

You can easily check this by printing the value of each received character, like

Serial.println((int)(BluetoothData));

You probably see the value for '0' (48), '1' (49), end of string '0' of end of line '13' or maybe '10' (new line).

• Michel Keijzers: you're welcome.

Answer 2

In the Arduino IDE you should select "No Line Ending" from the menu, instead of "New line". Otherwise you are sending an extra "\n".