Alright, I think I get what you're looking for... Check this out.
Using this TMP36, you could read the temperature and do things with that information.
// Source: https://learn.adafruit.com/tmp36-temperature-sensor/using-a-temp-sensor
int sensorPin = 0; // the analog pin the TMP36 is connected to
int redPin = 2;
int bluPin = 4;
int grePin = 5;
void setup(){}
void loop(){
int reading = analogRead(sensorPin);
// Convert the reading to voltage, use the voltage that is going to the TMP36
float voltage = reading * 3.3; // or 5.0
voltage /= 1024.0;
float temperatureC = (voltage - 0.5) * 100 //temperature in Celcius
if (temperatureC >= 70){
digitalWrite(bluPin, LOW); // turn off the blue LED
digitalWrite(grePin, LOW); // Turn off the Green LED
digitalWrite(redPin, HIGH); // Turn on the Red LED
}
else if ( 70 > temperatureC >= 25){
digitalWrite(bluPin, LOW); // turn off the blue LED
digitalWrite(grePin, HIGH); // Turn on the Green LED
digitalWrite(redPin, LOW); // Turn off the Red LED
}
else if ( temperatureC < 25) {
digitalWrite(bluPin, HIGH); // turn on the blue LED
digitalWrite(grePin, LOW); // Turn off the Green LED
digitalWrite(redPin, LOW); // Turn off the Red LED
}
}
What this would do is read the voltage from a TMP36 connected to Analog pin 0 and convert the voltage to a temperature. Then based on that information it will trigger an LED. If it's less than 25C it'll trigger a blue LED, indicating that it's cold. If it's higher than 25 but less than 70C, it'll trigger green, meaning lukewarm to the lower end of hot, higher than 70C triggers the red LED, indicating hot.
Is this something like what you were looking for?