Outside temperature monitor using Arduino Nano

1/* Temperature indication using 3 LEDs
2 *  alerts for dangerous road  conditions
3 *  Arduino NANO code
4 *  15-09-2021 by Procyon78
5 */
6
7const  int sensorPin = A0;
8// reference temperature, degrees Celcius
9const float  baselineTemp =4.0;
10
11void setup() {
12  // open a serial connection to display  values
13  Serial.begin(9600);
14  // set the LED pins as outputs
15  // pin  D2 = green LED
16  pinMode(2,OUTPUT);
17  // pin D3 = yellow LED
18  pinMode(3,OUTPUT);
19  //pin D4 = blueLED
20  pinMode(4,OUTPUT);
21   }
22
23void loop() {
24  //  read the value on AnalogIn pin 0 and store it in a variable
25  int sensorVal =  analogRead(sensorPin);
26
27  // send the 10-bit sensor value out the serial port
28  Serial.print("sensor Value: ");
29  Serial.print(sensorVal);
30
31  // convert  the ADC reading to voltage
32  float voltage = (sensorVal / 1024.0) * 5.0;
33
34  // Send the voltage level out the Serial port
35  Serial.print(", Volts: ");
36  Serial.print(voltage);
37
38  // convert the voltage to temperature in degrees  C
39  // the sensor changes 10 mV per degree
40  // the datasheet says there's  a 500 mV offset
41  // ((voltage - 500 mV) times 100)
42  Serial.print(", degrees  C: ");
43  float temperature = (voltage - 0.5) * 100;
44  Serial.println(temperature);
45
46  // measured temperature is 4 degrees or above = green LED on
47 if (temperature  >= baselineTemp){
48    digitalWrite(2, HIGH);
49    digitalWrite(3, LOW);
50    digitalWrite(4, LOW);
51
52 // measured temperature is between 0 and 4 degrees  = yellow LED on
53} else if (temperature >= baselineTemp-4 && temperature < baselineTemp){
54    digitalWrite(2, LOW);
55    digitalWrite(3, HIGH);
56    digitalWrite(4, LOW);
57
58  // measured temperature is lower than 0 degrees = blue LED on
59} else if (temperature  < baselineTemp-4){
60    digitalWrite(2, LOW);
61    digitalWrite(3, LOW);
62    digitalWrite(4, HIGH);
63  }
64    
65  delay(1000);
66}
67