Programming my CNC/fan to move based on temperature

Well knowing the position of each sensor is a must of course so a table with sensor ID, X, Y co-ordinate and its current reading

reading all sensors into the table (Memory), then locating the one with the highest reading

move servos/steppers to that X, Y co-ordinate, that should be a simple matter of emmiting Gcode or step and direction if your directly controlling the steppers. GCode is easier if the CNC is already wired to accept it

Well knowing the position of each sensor is a must of course so a table with sensor ID, X, Y co-ordinate and its current reading

reading all sensors into the table (Memory), then locating the one with the highest reading

move servos/steppers to that X, Y co-ordinate, that should be a simple matter of emmiting Gcode or step and direction if your directly controlling the steppers. GCode is easier if the CNC is already wired to accept it

Right now I'm using the step and direction/ the tone function. The problem I'm having is getting the cnc to stop moving once it reaches the temperature sensor with the highest temperature.  For now, I'm just using 3 sensors horizontally spaced a few inches apart and the fan is attached to the cnc.

I was thinking of coding it in such a way where when one of the temperatures start to decrease (by the fan) a few degrees, then it would stop (noTone).  But I have no idea how to do that.  Any idea?!

Heres the code i'm using to test this out

int tempOutput0=A0; //Defines analog pin 0 as integer tempoutput0

int tempOutput1=A1; //Defines analog pin 1 as integer tempoutput1

int tempOutput2=A2; //Defines analog pin 2 as integer tempoutput2

int fanPower=10; //Defines pin 10 as integer fanPower

int YDirection=2; //Defines pin 2 as integer YDirection

int YStep=3; //Defines pin 3 as integer YStep

void setup()

{

Serial.begin(9600);  //Directs to Serial library and defines baud rate

pinMode(fanPower, OUTPUT); //Defines the fan's power output

pinMode(YStep, OUTPUT); //Defines YStep as an OUTPUT (step of the motor)

pinMode(YDirection, OUTPUT); //Defines YDirection as an OUTPUT (motor direction)

}

void loop()

{

   digitalWrite(fanPower, HIGH);

int rawvoltage0=analogRead(tempOutput0);

float millivolts0= (rawvoltage0/1024.0) * 5000;

float fahrenheit0= millivolts0/10;

Serial.print(fahrenheit0);

Serial.println(" degrees Fahrenheit1, ");

delay(1000);

int rawvoltage1=analogRead(tempOutput1);

float millivolts1= (rawvoltage1/1024.0) * 5000;

float fahrenheit1= millivolts1/10;

Serial.print(fahrenheit1);

Serial.println(" degrees Fahrenheit2, ");

delay(1000);

if (fahrenheit0 > fahrenheit1)

{

digitalWrite(YDirection, HIGH); //set the motor direction

tone(YStep,400);

}

else 

{

digitalWrite(YDirection, LOW); //set the motor direction

tone(YStep,400);

//if fahrenheit0 or fahrenheit1 starts to decrease then stop

}

}