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Serial analog read (Read 2772 times)
Patric
Serial analog read
May 18th, 2009, 12:50pm  
I wrote this little program, and with the serial monitor in Arduino, it works. But to let it work in Processing, and continue read the analog value seems impossible. I searched allover the forum, and found no solution.
I think I am stupid not to get such simple program working in Processing.
Please help, I am a total beginner! (always 'programmed' in Liberty Basic)

Code:
int pin = 5; // analog pin
int in = 0; // in variabele

void setup()
{
Serial.begin(9600); // start serial communication
}

void loop()
{
  in = analogRead(pin);
  delay(1000);
Serial.print(in,DEC);
Serial.println(" milliVolt ");
 }
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« Last Edit: May 18th, 2009, 2:00pm by Patric »  
 
NoahBuddy
Re: Serial analog read
Reply #1 - May 18th, 2009, 3:07pm  
Since your message will be coming in as decimal (variable length) you will want to scan the serial input for a '\n'.

If you only want to print the result to the console then the example at
http://processing.org/reference/libraries/serial/Serial_readChar_.html

will do almost what you need. Change println() in draw() to print() and whatever comes in will be sent to the console.

If you want to use the number that the string represents, you will have to parse it as it comes in.

Hints: watch for '\n' character, it will be easier to parse without the " millivolt "

If you still have trouble, I have a working example. Wink
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Patric
Re: Serial analog read
Reply #2 - May 19th, 2009, 11:39am  
It works!!!
Thank you very much!
Now it also works in Liberty Basic, I just had to reset!
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Patric
Re: Serial analog read
Reply #3 - May 19th, 2009, 12:47pm  
Patric wrote on May 19th, 2009, 11:39am:
It works!!!
Thank you very much!
Now it also works in Liberty Basic, I just had to reset!


But I am very curious for your example!
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NoahBuddy
Re: Serial analog read
Reply #4 - May 19th, 2009, 1:16pm  
Kind of a slow oscilloscope
Code:

import processing.serial.*;

Serial port;
String buff = "";
int NEWLINE = 10;
int px = 0;
int threshold = 50;

int[] values = new int[512];
int val = 0;

void mouseReleased() {
  px = mouseX;
}

void setup() {
  size(512, 512);
  
  textFont(createFont("Arial", 14),14);
  
  println("Available serial ports:");
  println(Serial.list());
  
  port = new Serial(this, "COM5", 9600);  
}

void draw() {
  background(54);
  
  // Graph the stored values
  for (int i = 0; i < 511; i++) {
    stroke(0,255,0);
    line(i, height-1 - values[i], (i + 1), height-1 - values[i + 1]);
  }
  
  while (port.available() > 0)
    serCap(port.read());
    
  stroke(0,128,192);
  fill(255);
  line(px,0,px,height);
  text(val,20,10);
}

void serCap(int serial) {
  
  if (serial != NEWLINE) {// Keep reading characters until '\n' found
    buff += char(serial);
    
  } else {
    
    if (buff.length() == 4) {//change this to get more channels
	try {
	  // I used a fixed length hex string from the arduino
	  // Adding channels just means reading the next 4 bytes
	  val = unhex(buff.substring(0, 4));
	  
	} catch (Exception e) {}
    }
    
    // Clear the value of "buff" for next time
    buff = "";
    
    // Not optimized
    // Shift over the existing values to make room for the new one.
    for (int i = 0; i < 511; i++) {
	values[i] = values[i + 1];
    }
    
    // Add the received value to the array.
    values[511] = val;
  }
}
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Patric
Re: Serial analog read
Reply #5 - May 19th, 2009, 4:00pm  
Thank you! I will try it.
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