So i am sending text from bluetooth app that i made from MIT App Inventor to my arduino but the serial monitor shows numbers instead of alphabet.Im a new one and i can't really figured it out.
@yabedibedoo Installation and Troubleshooting is for Problems with the Arduino IDE itself NOT your project. It says so in the description of the section.
Therefore I have moved your post here. Please be more careful where you post in future.
Your code is printing out numbers because that is what you are asking it to do. The single quote mark like 'A' is taken by the computer to mean a number, and when you print it that is what you get.
However the double quotes mark is taken to mean a string, which is printed as a letter "A".
EVERYTHING in the processor/computer is a (binary) "number". It could represent an actual numerical value, or it could represent an alpha-numeric character, or a processor instruction, etc. The software has to "know" the context.
For example, an upper case "A" is represented by a decimal value of 65 (decimal). (ASCII Table).
you will really see the alphabet being printed out to the Serial monitor.
what is likely happening is that the MIT app is actually sending in the character as its ASCII number representation, so what we see on the console is a succession of characters properly printed by multiple succession of the loop reading one char and what was sent was an ASCII textual representation "65" may be and not 'A'
probably reading the documentation for this function would clarify what happens when you send an integer
Send1ByteNumber(number)
Decodes the given number String to an integer and writes it as one byte to the output stream.
If the number could not be decoded to an integer, or the integer would not fit in one byte, then the Form’s ErrorOccurred event is triggered and this method returns without writing any bytes to the output stream.
here OP is providing an int and not a String to the function
You haven't provided details of your hardware setup. You have an android device running your app and it is sending data via bluetooth.
But what device is receiving that data? Do you have an HC-05 type bluetooth connected to the Arduino board? Or is your PC receiving the bluetooth data directly without going thru the Arduino board?
Your output is repeating "65" and the backward question mark. So what is happening at the Android device? It sends "A" when the START_LAUNCHER button is pressed. Why is the output repeating?