Digital Thermometer (Electronics 101)

As promised I am adding the plans and code for the Digital Thermometer I wrote about in my blog post “Electronics 101”

The source code to run on the Arduino Uno once you have wired the above circuit is shown below: I will not go into detail on how to do this as you can learn it all on the Arduino website.

const int hot = 101;
const int cold = 97;

/********************************************************************/
// First we include the libraries
#include <OneWire.h> 
#include <DallasTemperature.h>
/********************************************************************/
// Data wire is plugged into pin 2 on the Arduino 
#define ONE_WIRE_BUS 2 
/********************************************************************/
// Setup a oneWire instance to communicate with any OneWire devices  
// (not just Maxim/Dallas temperature ICs) 
OneWire oneWire(ONE_WIRE_BUS); 
/********************************************************************/
// Pass our oneWire reference to Dallas Temperature. 
DallasTemperature sensors(&oneWire);
/********************************************************************/ 
void setup(void) 
{ 
  pinMode(3, OUTPUT); //green
  pinMode(4, OUTPUT); //red
  pinMode(5, OUTPUT); //blue
  digitalWrite(5, HIGH);
  digitalWrite(3, HIGH);
  digitalWrite(4, HIGH);
  delay(1000);  
  digitalWrite(5, HIGH);
  digitalWrite(3, LOW);
  digitalWrite(4, LOW);
  delay(1000);  
  digitalWrite(5, LOW);
  digitalWrite(3, HIGH);
  digitalWrite(4, LOW);
  delay(1000);  
  digitalWrite(5, LOW);
  digitalWrite(3, LOW);
  digitalWrite(4, HIGH);
  delay(1000);  
  digitalWrite(5, LOW);
  digitalWrite(3, LOW);
  digitalWrite(4, LOW);
  delay(1000);  
  
 // start serial port 
 Serial.begin(9600); 
 Serial.println("Dallas Temperature IC Control Library Demo"); 
 // Start up the library 
 sensors.begin(); 
} 
void loop(void) 
{ 
 // call sensors.requestTemperatures() to issue a global temperature 
 // request to all devices on the bus 
/********************************************************************/
 Serial.print(" Requesting temperatures..."); 
 sensors.requestTemperatures(); // Send the command to get temperature readings 
 Serial.println("DONE"); 
/********************************************************************/
 Serial.print("Temperature is: "); 
 int temp = sensors.getTempFByIndex(0);
   // Why "byIndex"?  
   // You can have more than one DS18B20 on the same bus.  
   // 0 refers to the first IC on the wire
 if (temp < cold) { //cold
  digitalWrite(5, HIGH);
  digitalWrite(3, LOW);
  digitalWrite(4, LOW);
  Serial.print(temp);
  Serial.println(" It's Cold.");
 }
 else if (temp >= hot) { //hot
  digitalWrite(5, LOW);
  digitalWrite(3, LOW);
  digitalWrite(4, HIGH);
  Serial.print(temp);
  Serial.println(" It's Hot.");
 }
 else { //fine
  digitalWrite(5, LOW);
  digitalWrite(3, HIGH);
  digitalWrite(4, LOW);
  Serial.print(temp);
  Serial.println(" It's nice.");
 }
   delay(1000);  
}