I want to send text over serial monitor to Arduino and make Arduino return that string back to me over serial monitor.
I have made this function which reads from serial input and returns a string object.
String readSerial() { String input; while(Serial.available() > 0) input.concat(Serial.read()); return input;}In theloop() I have:
if(Serial.available()) Serial.print(readSerial());If I just do something likeSerial.print("Hello world!"); everything is fine. But, if I try to return string object I get lot's of numbers.
I guessSerial.print doesn't know how to readString object and returns ASCII codes of characters or something?
[update]I have checked it, and it's indeed outputing ASCII codes. ForHi I get72105.
[update]I have updated myreadSerial function to use this :
input += (char)Serial.read();But now I'm getting carriage return and new line after every character:
[SEND] HiH(CR)i(CR)So, how can I make it return my text so that is readable?
2 Answers2
String.concat() takes aString as the second argument.Serial.read() returns anint. The compiler creates code that converts theint into aString similar to this:
input.concat(String(Serial.read()));This is not what you want.
Let's tell the compiler what you really want instead:
input.concat((char)Serial.read());This will tell the compiler to do the following:
input.concat(String((char)Serial.read()));We are now having the compiler call the correctString constructor, and the code will work as we expect.
- Yes, just figured that out. Thanks anyway.Reygoch– Reygoch2014-08-28 21:41:43 +00:00CommentedAug 28, 2014 at 21:41
Answering the other part of the question:
- you're getting CRs because your readString is just wrong.
The problem is that you don't wait for receiving a whole line of string. For example, if you press H on the serial monitor, then it is getting received and echoed back as if it would been the whole input, ending with a new line.
You might wish to check my answer atGet strings from Serial.read() that is usehttps://www.arduino.cc/en/Serial/ReadStringUntil which reads you the whole string until a separator (for example the whole string until it ends with a CR when you press Enter on the serial monitor).
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