How to send Arduino data to Processing and save it on PC

edited October 2016 in Arduino

Hello everybody!

I'm currently using Arduino to control an LED-strip (as semicircle) of 180 LEDs with an Arduino Uno board. My Arduino sketch has the following process operation: The LEDs are blinking one after another and start with a frequency of 50Hz and go down to 20 Hz before they switch forward. In addition to that, there is a button which can be pressed for instant switching, whereby the frequency and the respective LED-number are send over a serial port, so you can see them in the serial Monitor (Arduino).

Now I would like to save these data on my PC with help of Processing. I know that there are many tutorials and articles to find but I only found Processing-codes to save sensorsinput. I guess there is a simple the solution, but I'm a total greenhorn in programming (especially Processing) and would like an opinion about my current "work" (I don't even know if my code is even sligthly correct :D)

And of course my crappy (sorry for vile language^^) Processing sketch: Note that the framework is from codes I found in other posts!

import processing.serial.*;

Serial myPort; //creates a software serial port
Table dataTable; //table to store values.

int numReadings = 500; //keeps track of how many readings one would like to take before writing the file. 
int readingCounter = 0; //counts each reading to compare to numReadings. 
float Winkel;
String Wink;

String fileName;
void setup()
  String portName = Serial.list()[0]; 

  myPort = new Serial(this, portName, 9600); //set up your port to listen to the serial port

  dataTable = new Table();
  dataTable.addColumn("id"); //This column stores a unique identifier for each record. We will just count up from 0 - so the first reading will be ID 0, the second will be ID 1, etc. 

  //the following adds columns for time.

  //columns for values

  void draw() { 
    TableRow newRow = dataTable.addRow(); //add a row for this new reading
    newRow.setInt("id", dataTable.lastRowIndex());//record a unique identifier (the row's index)

    Wink = myPort.readString();

    //record time stamp
    newRow.setInt("year", year());
    newRow.setInt("month", month());
    newRow.setInt("day", day());
    newRow.setInt("hour", hour());
    newRow.setInt("minute", minute());
    newRow.setInt("second", second());

    //record information. 
    newRow.setFloat("Winkel", Winkel);

    readingCounter++; //optional, use if you'd like to write your file every numReadings reading cycles

    //saves the table as a csv in the same folder as the sketch every numReadings. 
    if (readingCounter % numReadings ==0)//The % is a modulus, a math operator that signifies remainder after division. The if statement checks if readingCounter is a multiple of numReadings (the remainder of readingCounter/numReadings is 0)
      fileName = str(year()) + str(month()) + str(day()) + str(dataTable.lastRowIndex()); //filename: year+month+day+readingCounter
      saveTable(dataTable, fileName); // save it to computer.

The idea here is just to get the frequency (in German: Frequenz) and angle (in German: Winkel) data in a file. It doesn't have to look fancy. I do hope that I provided you with every necessary information! I can also add a screenshot of the serial monitor from Arduino by request.

Many thanks in advance for your help!


  • Break your problem down into smaller steps.

    Step 1: Can you write a simple Processing sketch that simply outputs a single value to a file? You can hardcode everything, just get it working.

    Step 2: Can you modify that simple sketch so that it outputs a variable? Something simply like mouseX would be fine.

    Step 3: Can you create a simple Arduino program that sends a single value to Processing? Again, the value can be hardcoded. When you receive it in Processing, just print it to the console for now.

    Step 4: Can you modify that simple program to store the value from Arduino into a variable?

    Step 5: Can you combine the ideas from your two separate programs to store the variable (which you're getting from Arduino) into a file?

    Step 6: Modify your program to send whatever you want from the Arduino, then store that in a file in Processing.

    Take these steps one at a time, and post an MCVE if you get stuck on a specific step. You'll have much better luck programming this way rather than trying to get random code you found on the internet to work. Good luck.

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