collecting, averaging & ignoring duplicate serial data

rossdickinson

Hey, I'm trying to receive data from the serial port, collect a sample group ('numReadings'), average it ('average'), and print it to screen only if the new average ('average') isn't equal to the old average ('previousAverage').

Below I have some really horrible code, trying to illustrate the idea, but i'm having trouble pulling it all together and amn't 100% if this is the best way to do it.

Would really appreciate if anyone was able to offer advice!

Cheers,

Ross

import processing.serial.*;

Serial myPort;
int numReadings = 512;
int readIndex = 0;
int total = 0;
int average = 0;
int previousAverage = 0;
int[] readings = new int[numReadings];

void setup() {

  size(640, 640);
  background(30);
  myPort = new Serial(this, Serial.list()[0], 9600);
  myPort.bufferUntil('n');
}

void draw() {
}

void serialEvent (Serial MyPort) {

    for (int thisReading = 0; thisReading < numReadings; thisReading++) {
    readings[thisReading] = 0;
  }

  String inString = myPort.readStringUntil('\n');

  if (inString != null){
    inString = trim(inString);
  }

  total = total - readings[readIndex];
  readings[readIndex] = inString;
  total = total + readings[readIndex];
  readIndex = readIndex + 1;


  if (readIndex >= numReadings) {
  readIndex = 0;
  }

average = total / numReadings;

if (average != previousAverage) {
println(average);
}
  previousAverage = average;
}

Processing 2.2.1 (i need to update i know) Windows 8

_vk

// I think the idea is something like  this.
// I made a fake serial input
// don't know the kind of data you get...
// the equality is based in int values, but maybe
// average should be a float... 


int numReadings = 512;
int average = 0;
int previousAverage = 0;
int[] readings = new int[numReadings];


int index = 0;



void setup() {

  size(64, 64);
  background(30);
}

void draw() {

  //convert to int to add to array
  readings[index] = int(serialMockup());

  // so we know it is happening
  if (index%50 == 0) {
    println("receiving data [" + index +"]");
  }

  // next slot
  index++;
  index%=readings.length;



  // a full buffer
  if (index == 0) {

    average = average(readings);

    // new average?
    if (average != previousAverage) {
      println("\nDifer! New average = "+ average + "   last average = " + previousAverage);
    } else {
      //the line below shouldn't be...
      println("\naverage  "  + average + " is equal to  last average = " + previousAverage + " shoudn't print");
    }

    previousAverage = average;
    average = 0;
    readings = new int[numReadings];
  }
}

int average(int[] a) {
  float tot = 0;
  for (int i = 0; i < a.length; i++) {
    tot+=a[i];
  }
  return round(tot/float(a.length));
}



String serialMockup() {
  return nf(int(random(100)), 2);
}

rossdickinson

@_vk thanks so much, this is exactly what I was trying to do. Will edit the code to feed data in from the serial port.

Cheers! :)