Processing not finding Arduino Uno

[SWijnen]

Hey everyone,

I’m working on a project for school, and for some reason, my environment is messing up. The deadline is upcoming Friday, so I’m still researching some solutions while also making this post. Thanks for your help!

The problem:

I have an Arduino Uno that communicates data to Processing 4.2, but Processing is not detecting the Arduino anymore. The connection always worked fine, but without any changes in both the codes, it suddenly stopped. Testing the same code and Arduino on a different laptop does work, Processing is then able to detect the Arduino. The Arduino IDE is able to see the Uno, and I have the serial monitor off. With the IDE closed, the problem still exists.

Things I already noticed:

• The Processing code runs/starts better and faster on a different laptop (of the same type, just a year newer)
• Not the from this problem, but maybe good to know: A few weeks back, I’ve had the issue that the Arduino IDE did not saw a different microcontroller. While a secondair program was able to see the same microcontroller. The IDE was not able to detect the mc, even with the program closed and my laptop restarted.

The setup:

Arduino Uno with a MPR121 Capacitieve Touch Sensor Module connected to it. The Arduino sends an ‘id’ number and ‘value’ number through the serial monitor whenever there is a change on that ‘id’. (see code below)

Processing visualizes the incoming ‘id’ and ‘value’. This code is made for quick debugging (but also takes long to start up (meaning the window pops up, and it takes long for the code to go into the draw() function.

The codes:

Processing code:

import processing.serial.*;

Serial myPort;  // Create object from Serial class
String val;     // Data received from the serial port
boolean SerialAvailable = false;

int incommingSerialId = 0;
int valueFromSerial = 0;
int[] interaction = new int[13];

color bgColor;

void setup() {
  size(400, 250);
  
  try {
    String portName = Serial.list()[0]; //change the 0 to a 1 or 2 etc. to match your port
    myPort = new Serial(this, portName, 9600);
    myPort.bufferUntil('\n');
    SerialAvailable = true;
    println("arduino found");
    bgColor = color(250);
    fill(0);
  }
  catch(Exception e) {
    println("arduino not found");
    SerialAvailable = false;
    bgColor = color(100, 0, 0);
    fill(255);
  }

  textSize(60);
}

void draw() {
  background(bgColor);
  CheckSerialCom();

  push();
  String sc2 = incommingSerialId + ": " + interaction[incommingSerialId];
  text(sc2, 40, 120);
  
  pop();
  
  println(interaction[2]);
}

void CheckSerialCom() {
  if (SerialAvailable) {
    SerialCom();
  } else {
    
    for (int i = 0; i < 9; i++) {
      if (keyPressed && ((key >= '0' && key <= '9') || key == ' ')) {
        int value = key - '0';
        if (value == i || key == ' ') {
          interaction[i] = 1;
        }
      } else {
        interaction[i] = 0;
      }
      UpdateInteraction(i,interaction[i]);
    }
  }
}

void SerialCom() {
  // If data is available,
  if ( myPort.available() > 0) {
    val = myPort.readStringUntil('\n');         // read it and store it in val

    if (val != null) {
      val = trim(val);      // removes whitespace + \r + \n

      String[] parts = split(val, ';');

      if (parts.length == 2) {
        int id = int(parts[0]);
        int value = int(parts[1]);

        UpdateInteraction(id, value);
      }
    }
  }
}

void UpdateInteraction(int id, int value) {
  incommingSerialId = id;
  interaction[id] = value;
}

Arduino code:

/*********************************************************
This is a library for the MPR121 12-channel Capacitive touch sensor

Designed specifically to work with the MPR121 Breakout in the Adafruit shop 
  ----> https://www.adafruit.com/products/

These sensors use I2C communicate, at least 2 pins are required 
to interface

Adafruit invests time and resources providing this open source code, 
please support Adafruit and open-source hardware by purchasing 
products from Adafruit!

Written by Limor Fried/Ladyada for Adafruit Industries.  
BSD license, all text above must be included in any redistribution
**********************************************************/

#include <Wire.h>
#include "Adafruit_MPR121.h"

#ifndef _BV
#define _BV(bit) (1 << (bit))
#endif

// You can have up to 4 on one i2c bus but one is enough for testing!
Adafruit_MPR121 cap = Adafruit_MPR121();

// Keeps track of the last pins touched
// so we know when buttons are 'released'
uint16_t lasttouched = 0;
uint16_t currtouched = 0;
uint16_t baseln;
uint16_t filterln;

void setup() {
  Serial.begin(9600);

  while (!Serial) {  // needed to keep leonardo/micro from starting too fast!
    delay(10);
  }

  //Serial.println("Adafruit MPR121 Capacitive Touch sensor test");

  // Default address is 0x5A, if tied to 3.3V its 0x5B
  // If tied to SDA its 0x5C and if SCL then 0x5D
  if (!cap.begin(0x5A)) {
    //Serial.println("MPR121 not found, check wiring?");
    while (1)
      ;
  }
  //Serial.println("MPR121 found!");
}

void loop() {
  // Get the currently touched pads
  currtouched = cap.touched();

  for (uint8_t i = 0; i < 12; i++) {
    // it if *is* touched and *wasnt* touched before, alert!
    if ((currtouched & _BV(i)) && !(lasttouched & _BV(i))) {
      Serial.print(i);
      Serial.print(";");
      Serial.println("1");
    }
    // if it *was* touched and now *isnt*, alert!
    if (!(currtouched & _BV(i)) && (lasttouched & _BV(i))) {
      Serial.print(i);
      Serial.print(";");
      Serial.println("0");
    }
  }

  // reset our state
  lasttouched = currtouched;

  delay(100);
}

[glv]

@SWijnen

Processing is not detecting the Arduino anymore.

Has the COM port changed? It is not always the first one in the array.

Try the code here and change COM port as required:

list() / Libraries

I always have this in my code to verify:

// List all the available serial ports:
printArray(Serial.list());

On my PC:

It may not be that simple but it is a starting point.

Simplify your code when testing to isolate issues.

I did not have your hardware and reduced it to test what I could:

Receive:

import processing.serial.*;

Serial myPort;  // Create object from Serial class
String val;     // Data received from the serial port
boolean SerialAvailable = false;

void setup() {
  size(400, 250);

  try {
    String portName = Serial.list()[2]; //change the 0 to a 1 or 2 etc. to match your port
    myPort = new Serial(this, portName, 9600);
    myPort.bufferUntil('\n');
    SerialAvailable = true;
    println("Arduino found");
  }
  catch(Exception e) {
    println("Arduino not found");
    SerialAvailable = false;
  }
}

void draw() {
  CheckSerialCom();
}

void CheckSerialCom() {
  if (SerialAvailable) {
    SerialCom();
  }
}

void SerialCom() {
  // If data is available,
  if ( myPort.available() > 0) {
    val = myPort.readStringUntil('\n');         // read it and store it in val

    if (val != null) {
      val = trim(val);      // removes whitespace + \r + \n
      println(val);
    }
  }
}

Send:

int i;

void setup() {
  Serial.begin(9600);

  while (!Serial) {
    delay(10);
  }
}

void loop() {
  // Get the currently touched pads

      Serial.print(millis());
      Serial.print(",");
      Serial.print(i++);
      Serial.println();
      
  delay(100);
}

The above worked when selecting the correct COM port.

It did not find the COM port once time and I did a power reset unplugging USB (and plugging in).

Operating system?
Version of Processing in different systems?
Arduino IDE? Should not impact communication unless monitor is running.

:)

[SWijnen]

@glv

printArray(Serial.list());

Thank you! I had the wrong com port I think. But for me that raises another few questions (I’ll also look into that myself).

Why does it work all the time and suddenly changes the array of COM ports (or the order of it)?

Is there a way to automatically connect to the right com port?

[RichardDL]

Are you using a Windows PC? Try plugging the Ard into different usb sockets and see what com port you have. Some Ard with the CH340 chip change port number with USB socket. It’s a feature. (?)

[glv]

Hello @SWijnen ,

@SWijnen

Thank you! I had the wrong com port I think.

You need to know which COM port you are using moving forward to navigate this and find a solution.

@SWijnen

Why does it work all the time and suddenly changes the array of COM ports (or the order of it)?

A search for USB Enumeration will get you started and then add “Arduino”.
This applies to all USB devices connected.
This behavior may be hardware dependent (see last post).

@SWijnen

Is there a way to automatically connect to the right com port?

As you have observed the COM port may change depending on PC and may also change using a different USB Port.
There are different strategies to try for selecting this automatically in code; there is no simple solution.

You can manually assign a COM port to the device on the Windows PC in use:

I have used the jSerialComm library to detect the COM port by name and port:

More details about COM ports

Hello @bask185, This will provide more details: This is the list of COM ports using the jSerialComm library: [image] Those other COM ports are your virtual COM ports: [image] And your ports: [image] This is the list of COM ports using Processing Serial library: [image]

You can use it alongside the Processing Serial library:

The jSerialComm library gives you a name to find!
You will have to add the library and write the code to iterate through the array to find the COM port you want for the “Arduino Uno”.

A search in the forum may yield other approaches to this with Processing (Java).
There are other approaches with Windows and other programming languages but this may be beyond scope of this project.

To better assist please share:

• Operating system
  Windows 10, etc.
• Hardware.
  Arduino can be a any number of boards including original and clones.
• Processing version
  You stated 4.2.
  Keep in mind the latest version is 4.4.10.
• Arduino IDE and version. Should not impact COM port.
• Anything else that may be important!

@SWijnen

The deadline is upcoming Friday, so I’m still researching some solutions while also making this post. Thanks for your help!

You may just have to assign manually in the code until this is sorted out.
Prioritize what needs to be done to complete your project.
Keep notes!
This is all good stuff to discuss in your project!

Hint:

It is important to use established naming conventions and the correct capitalization for technical terms in posts, project documentation and future careers.
COM for example and not “com”.

Reference:
COM (hardware interface) - Wikipedia

:)