Love-O-Meter

For my first project I wanted to create a temperature reader that made LEDs turn on depending on the temperature read by the sensor.

Step 1: The Materials

• Arduino Uno
• Breadboard
• 3 red LEDs
• Jumper wires
• Temperature Sensor

Step 2: Physical Creative

• To start I connected the breadboard to GND (ground) and 5V (voltage)
• Next I inserted the LEDs, 2 220 resistors for each and 3 yellow jumpers to attach them to the Arduino
• Then I inserted the TMP (temperature) sensor and the appropriate jumpers for that as well.

Step 3: Code

const int sensorPin = A0;
const float baselineTemp = 20.0;

void setup(){
  Serial.begin(9600); //open a serial port
  for(int pinNumber = 2; pinNumber<5; pinNumber++){
    pinMode(pinNumber, OUTPUT);
    digitalWrite(pinNumber, LOW);
  }
}

void loop(){
  int sensorVal = analogRead(sensorPin);
  Serial.print("Sensor Value: ");
  Serial.print(sensorVal);
 
  //convert sensor reading to voltage
  float voltage = (sensorVal/1024.0) * 5.0;
  Serial.print(", Volts: ");
  Serial.print(voltage);
  Serial.print(", degrees: ");
  //convert voltage to temp
  float temperature = (voltage - .5) * 100;
  Serial.println(temperature);
 
  if(temperature < baselineTemp){
    digitalWrite(2, LOW);
    digitalWrite(3, LOW);
    digitalWrite(4, LOW);
  }else if(temperature >= baselineTemp+2 && temperature < baselineTemp+4){
    digitalWrite(2, HIGH);
    digitalWrite(3, LOW);
    digitalWrite(4, LOW);
  }else if(temperature >= baselineTemp+4 && temperature < baselineTemp+6){
    digitalWrite(2, HIGH);
    digitalWrite(3, HIGH);
    digitalWrite(4, LOW);
  }else if(temperature >= baselineTemp+6){
    digitalWrite(2, HIGH);
    digitalWrite(3, HIGH);
    digitalWrite(4, HIGH);
  }
 
  delay(3);
}

Reflection:

This was day 1 of the Arduino Project. I did not focus on one project and expand because I wanted to see how many different programs I could discover. I had some difficulty with the temperature sensor and I had to work on it outside of class. There was a point when the temperature sensor actually became burning hot and actually burned me...so I figured something wasn't right. After a few adjustments in my code I was able to get my "Love-o-meter" working.