Can anyone confirm this for me although I have tested it myself but when I send a string of data from my android app and send it to arduino say for example data = bluetoothPort.read(); inside an if statement then when I try to use the data in another if statement for example Serial.print(data); inside another if statement it will only show a blank line which let me believe that none of the data are saved. also when a receiving a string of data for example a string of abcde and send it to arduino for example data = bluetoothport.read() and then Serial.print(data) the serial monitor shows abcde as expected but what really happens is data has the value of a then prints then replace by b then print then replace by c then print then replace by d then print then replace by e. Am I wrong or somehow right? are there any work around or parts I need that will make me store data as a whole so that I can use it for other thread or a better code to store string of data?

#include <IRremote.h>
#include <SoftwareSerial.h>

SoftwareSerial bluetoothPort(4,5);
const int RECV_PIN = 12;
const int SEND_PIN = 13;

IRsend irsend;
IRrecv irrecv(RECV_PIN);

decode_results results;
char data;

void setup() 

void loop() 
   if (bluetoothPort.available() > 0)
       data = bluetoothPort.read(); //received bluetooth data from android

       irreceived(); //received IR code from a remote then sends it to my android
       irsend.sendNEC(data, 32)

 void irreceived()
     Serial.println(results.value, HEX);   //receive value of 489010   
     bluetoothPort.println(results.value, HEX); //send value to android

so the above is a simple sketch that receive data from a remote controller then send it to my android app then when I resend it back to my arduino I would like the data to be able to receive all the data instead of saving it per letter/number and also be able to store it for other statement to use.

1 Answer 1


Serial communications only consist of one character. That is what serial is - the sending of one character at a time.

How you then deal with those characters, combining them into strings, interpreting them as numbers, whatever, is completely up to you to program.

There is no such thing as a string in serial communications. There is only the character.

The Arduino API has a few (badly implemented IMHO) helper functions that can get a whole string (kinda), but it is much better (both from a learning perspective and an implementation perspective) to do it yourself.

I have a little tutorial here that may help you get to grips with it.

  • This works great for me at best even and I love it. I got one question though... I am developing a universal remote control Arduino paired with Android app and thanks to your help I was able to receive the code sent from a remote control and send to the android app and on a push of a button the Arduino received(thanks to your help) and sends using IR emitter... the usual way to send was irsend.sendNEC(0x40BFEA15, 32); but when I do this irsend.sendNEC(buffer, 32); the buffer has 0x40BFEA15 value it does not work? any idea or tips or work around on how to make it work?
    – User9124
    Jan 26, 2017 at 14:11
  • You have a string, and you need a 32-bit unsigned integer. You need to parse the string and convert it to an integer. strtoul() may help you there.
    – Majenko
    Jan 26, 2017 at 14:33
  • Through trial and error I have manage to figure out that I need when I do this long number = 0x40BFEA15; then this irsend.sendNEC(number, 32) it works so the next question is... how do I convert the received Bluetooth data on a char buffer` that contains 0x40BFEA15 into a long that will retain the value of buffer..? or is there other way to receive bluetooth data as a long instead of a char.? silly question but I know I am near to finish with this one.
    – User9124
    Jan 26, 2017 at 15:31
  • I told you the function to use just now.
    – Majenko
    Jan 26, 2017 at 16:25
  • just did this long data = strtoul(buffer, NULL, 16); then Serial.print(val); and it gives me a combination of numbers so I did this Serial.print(val, HEX); and gives me 40BFEA15 and was expecting the result to be 0x40BFEA15, it omits the first two character :"0x" am I doing it wrong?
    – User9124
    Jan 26, 2017 at 18:44

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