Reading JSON using serial communication on Arduino

[renno-bih]

This library is great, helps me sending JSON data from Arduino to Web. But I also want to send JSON data from web to Arduino to control some of devices.
At the moment I'm using serial interface for communication between Arduino and Node.js script. I managed to send JSON stream to Arduino but I cannot store it to variable that can be parsed using this library.

I tried this method to read each line:

 while (Serial.available() > 0)
    {
        char recieved = Serial.read();
        inData += recieved; 

        // Process message when new line character is recieved
        if (recieved == '\n')
        {
            Serial.print("Arduino Received: ");
            Serial.print(inData);

        }   
            inData = ""; // Clear recieved buffer
        }
    }

But this example doesn't work for reading line of JSON data.
Any idea why?

[bblanchon]

Maybe the end of line is not \n, it could be \r or \0.
Also, you should try Serial.readBytesUntil()

[renno-bih]

Hmmm, not sure how to use Serial.readBytesUntil() with strings .... but I tried this:

if(Serial.available() > 0)
    {
        inData = Serial.readStringUntil('\n');
       Serial.println("data: "+inData);

       inData="";
     }

And strange thing is happening again ...
For input:

{"type_json":1,"count_json":68,"codeValue_json":"20df40bf","bits_json":32}

I get this output:

data: {"type_json":1,"count_json":68,"codeValue_json":"20df40bf","bit

Any reason why it doesn't store the whole line of input text?

[renno-bih]

I solved problem.
I was using delay function in my loop. Looks like delay function has influence on readStringUntil() ...

Organizing my code in separate timers and leaving readStringUntil() in loop fixed my problem.

[q2dg]

readStringUntil() has a timeout configurable with setTimeout()

[pilotak]

how do you parse your variable "inData" to JSON?