How to make Arduino to stop updating i2c data when meet a condition and wait until it receives another serial input from processing?

Question

I am currently making a robot with Arduino Uno, D6T omron thermal sensor (i2c sensor) and some other sensors. My thermal sensor will always update the data in array form. It will display 4 data arrays every 1 second.

I wish to have my Arduino send out a string "found" over serial when it meet a condition, and thermal sensor will stop updating my data. Thermal sensor and Arduino will just have to wait until the user sends a selection, jump to the selected function, and thermal sensor will start updating data again after that. I am new to coding, any suggestion on how to make my arduino and sensor to wait? Thank you guys! =)

Attached below is my code. (Arduino Sketch):

#include <Wire.h>
#include <WireExt.h>

#define D6T_addr 0x0A
#define D6T_cmd 0x4C

int rbuf[35];
float tdata[16];
float t_PTAT;

const int S_DATATRANSFER = 0;
const int S_WAIT = 1;
const int S_STOPTRANSFER = 2;
const int S_CONFIRMATION = 3;
const int S_ALLSTOP = 4;

float left_sum, right_sum, center_sum;

//-----------------------------------------------------------------------------

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

}

void loop()
{

static int state = S_DATATRANSFER;


    switch(state)
    {

    case S_DATATRANSFER:
        //Calculate temp
        //serialprint temp
        int i;

        if (Serial.available() > 0) 
        {     
                      char inByte = Serial.read();     
                      if (inByte == '1') 
            {  //processing will send one byte to arduino if ready     

                Wire.beginTransmission(D6T_addr);
                Wire.write(D6T_cmd);
                Wire.endTransmission();

            if (WireExt.beginReception(D6T_addr) >= 0) 
                {
                    i = 0;
                    for (i = 0; i < 35; i++) 
                    {
                        rbuf[i] = WireExt.get_byte();
                    }
                    WireExt.endReception();

                    t_PTAT = (rbuf[0]+(rbuf[1]<<8))*0.1;
                    for (i = 0; i < 16; i++) 
                    {
                        tdata[i]=(rbuf[(i*2+2)]+(rbuf[(i*2+3)]<<8))*0.1;
                    }
                }

                right_sum= tdata[0]+ tdata[4] + tdata[8] + tdata[12];
                left_sum= tdata[3] + tdata[7] + tdata[11] + tdata[15];
                center_sum= tdata[5] + tdata[6] + tdata[9] + tdata[10];            
                output_csv();  

               }
                      }
        state = S_WAIT;
        break;

    case S_WAIT:
        if (center_sum > 35*4)
        {
        state = S_STOPTRANSFER;
        }
        else
        {
        state = S_DATATRANSFER;
        }
        break;

    case S_STOPTRANSFER:

        Serial.println("F");
                delay(300);

        state = S_CONFIRMATION;

        break;

    case S_CONFIRMATION:
        while (Serial.available())
        {
         char val = Serial.read();
            if (val == '2')
            {
                state = S_ALLSTOP;
            }
            else if (val == '3')
            {
                state = S_DATATRANSFER; 
                }  
                        else if (val == '1')
                        {
                                state = S_DATATRANSFER;
                        }
                }   

        break;

        case S_ALLSTOP:

        break;


    }
}

void output_csv() 
{
  for (int i = 0; i < 16; i++) 
  {
    Serial.print(tdata[i]);
    if (i < 15) 
    {
      Serial.print(",");
    } 
    else 
    {
      Serial.println();
    }
  }
}

Attached below is my code in processing:

import processing.serial.*;
import controlP5.*;
import javax.swing.JOptionPane.*;
import com.onlylemi.processing.android.capture.*;
ControlP5 cp5;
javax.swing.JOptionPane JOptionPane;

AndroidCamera ac;
PImage img;
Textlabel myTextlabelA, myTextlabelB;
boolean canStart = true;
boolean canInput = false;
boolean Start = false;
boolean Start_camera = false;
String typedText = "Comments: ";
PFont font;
String command = "";
String confirm;
String found;

PImage carImage;
float[] tdata = new float[17]; 
float tptat; // PTAT
String portName; 
//int serialport = 0; 

String buf; 
float colourGreen; //change green in relation to temperature 

int lbTemp = 25; //lowest relative temperature
int hbTemp = 35; //highest relative temperature 
Serial myPort;  // Create object from Serial class


void setup() {
  size(1366,768);
  //background(#FFFFFF);
  background(ControlP5.BLACK);
  //println(Serial.list());
  //portName = Serial.list()[serialport];
  myPort = new Serial(this, "COM15", 9600);
  myPort.clear();
  cp5 = new ControlP5(this);
  ac = new AndroidCamera(720, 480, 30);
  ac.start();

  myTextlabelA = cp5.addTextlabel("label")
                    .setText("GUI of Alive Human Detection System.")
                    .setPosition(120,10)
                    .setColorValue(#FFFAF0)
                    .setFont(createFont("Georgia",20))
                    ;

  cp5.addButton("Start")
     .setPosition(115, 670)
     .setSize(100,30)
     ;

  cp5.addButton("Stop")
     .setPosition(375, 670)
     .setSize(100,30)
     ;
  cp5.addButton("Start Camera")
     .setPosition(799, 670)
     .setSize(100,30)
     ;
}

public void Start(int theValue) {
  println("Initialising...");
  println("Connected.");
  //start displaying
 // carImage = loadImage(".png");
  Start = !Start;
}

public void Stop(int theValue) {
  println("Shuting Down...");
  //finish = loadImage("robot.png");
  //image(finish,30,64);
  myPort.write(0x02);
  Start = !Start;
  //strokeWeight(0);
}

public void Start_camera(int theValue) {
  println("Initialising...");
  println("Connected.");
  //start displaying
 // carImage = loadImage(".png");
  Start_camera = !Start_camera;
}

void draw() 
{
  //if (Start_camera){
  //img = ac.getCameraImage();
  //image(img, 610, 0);
  //}
  if (Start){

    myPort.write('1'); 
    delay(100);
    while (myPort.available() > 0) { 
    delay(300);  
    buf = myPort.readStringUntil('\n');
    if (buf.equals("F")){
    int dialogResult = JOptionPane.showConfirmDialog (null, "Human found? Please Confirm!!", "Alert!", JOptionPane.YES_NO_OPTION, JOptionPane.QUESTION_MESSAGE);
    if(dialogResult == JOptionPane.YES_OPTION)
    {
    fill(255,0,0);
    rect(100,670,50,30);
    myPort.write('2');
    }
    else if(dialogResult == JOptionPane.NO_OPTION)
    {
    fill(0,255,0);
    rect(100,670,50,30);
    myPort.write('3');
    }
    }
    else{
    myPort.clear();
    tdata = float(split(buf, ','));  
    for (int i = 0; i <16; i++) { 
    colourGreen = map(tdata[i],lbTemp,hbTemp,255,0);
    fill (255,colourGreen,0);

      if (i == 0)
    { rect(450,64,150,150);}
      else if (i == 1)
    { rect(300,64,150,150);}
      else if (i == 2)
    { rect(150,64,150,150);}
      else if (i == 3)
    { rect(0,64,150,150);}
      else if (i == 4)
    { rect(450,214,150,150);}
      else if (i == 5)
    { rect(300,214,150,150);}
      else if (i == 6)
    { rect(150,214,150,150);}
      else if (i == 7)
    { rect(0,214,150,150);}
      else if (i == 8)
    { rect(450,364,150,150);}
      else if (i == 9)
    { rect(300,364,150,150);}
      else if (i == 10)
    { rect(150,364,150,150);}
      else if (i == 11)
    { rect(0,364,150,150);}
      else if (i == 12)
    { rect(450,514,150,150);}
      else if (i == 13)
    { rect(300,514,150,150);}
      else if (i == 14)
    { rect(150,514,150,150);}
      else if (i == 15)
    { rect(0,514,150,150); }

    if (tdata[i]<5) {fill(255);} else {fill(0);}
      if (i ==0)
      {
      textAlign(CENTER, CENTER);
      textSize(20);
      text(str(tdata[i]),525, 139);}
      else if (i == 1)
      {
      textAlign(CENTER, CENTER);
      textSize(20);
      text(str(tdata[i]),375, 139);
      }
      else if (i == 2)
      {
      textAlign(CENTER, CENTER);
      textSize(20);
      text(str(tdata[i]), 225, 139);
      }
      else if (i == 3)
      {
      textAlign(CENTER, CENTER);
      textSize(20);
      text(str(tdata[i]),75, 139); 
      }
      else if (i == 4)
      {
      textAlign(CENTER, CENTER);
      textSize(20);
      text(str(tdata[i]), 525, 289); 
      }
      else if (i == 5)
      {
      textAlign(CENTER, CENTER);
      textSize(20);
      text(str(tdata[i]), 375, 289);  
      }
      else if (i == 6)
      {
      textAlign(CENTER, CENTER);
      textSize(20);
      text(str(tdata[i]), 225, 289);  
      }
      else if (i == 7)
      {
      textAlign(CENTER, CENTER);
      textSize(20);
      text(str(tdata[i]), 75, 289); 
      }
      else if (i == 8)
      {
      textAlign(CENTER, CENTER);
      textSize(20);
      text(str(tdata[i]), 525, 439);
      }
      else if (i == 9)
      {
      textAlign(CENTER, CENTER);
      textSize(20);
      text(str(tdata[i]), 375, 439);  
      }
      else if (i == 10)
      {
      textAlign(CENTER, CENTER);
      textSize(20);
      text(str(tdata[i]), 225, 439);
      }
      else if (i == 11)
      {
      textAlign(CENTER, CENTER);
      textSize(20);
      text(str(tdata[i]), 75, 439);
      }
      else if (i == 12)
      {
      textAlign(CENTER, CENTER);
      textSize(20);
      text(str(tdata[i]), 525, 592);  
      }
      else if (i == 13)
      {
      textAlign(CENTER, CENTER);
      textSize(20);
      text(str(tdata[i]), 375, 592); 
      }
      else if (i == 14)
      {
      textAlign(CENTER, CENTER);
      textSize(20);
      text(str(tdata[i]), 225, 592);
      }
      else if (i == 15)
      {
      textAlign(CENTER, CENTER);
      textSize(20);
      text(str(tdata[i]), 75, 592);  
      }
    }
    delay(350);  
  }
    }
    }
}

Answer 1

Implement a state machine first in your code for each state:

1) Sending i2c data.

2) Not sending i2c data.

And identify the conditions necessary to switch states:

1 to 2 when condition meet.

2 to 1 when command received.

Then drop your code into the state machine's code.

Read about state machines here and here.

Answer 2

Create a flow chart of the entire process you want to happen. Once you proof your flow chart to cover all possible functions, you can create the logic, control, and subroutines that are needed. If you have a good book on Arduino programming, and how I2C works, you will know that the I2c display will hold whatever data you wish until you change it. Also, you probably know that you can chain a whole bunch of I2c devices, no matter if they are displays, or anything else, so each device will hold its own data independent of the others. Any updating is under your control in programming. You might also look into using interrupts for some of your program control. Sensors don't push data, the processor reads the data, and your program is in control of how often and when the data is read, and what it does with the data. The exception to your program being in control, is when you use interrupts. You should be storing the data so you will always have access to it for program examination and possible decision making. Lastly, to increase the abilities of your system, consider using one master Arduino, and several slave Arduino's. Some of the slaves, depending on what you want them to do, can be very small. Look at the tiny85. Some of the boards with the Tiny85 are the size of a postage stamp. I hope some of these suggestions are helpful to you.