KY-028 Digital Temperature Sensor Module

Digital Temperature Sensor KY-028 for Arduino, it measures temperature changes based on the thermistor resistance. This module has both digital and analog outputs, there's a potentiometer to adjusts the detection threshold on the digital interface.

The KY-028 consist of a  of a NTC thermistor, a LM393 dual differential comparator a 3296W trimmer potentiometer, six resistors and two indicator LEDs. The board features an analog and a digital output.

Connect the board's analog output (A0) to pin A0 on the Arduino and the digital output (D0) to pin 3. Connect the power line (+) and ground (G) to 5V and GND respectively.

When the temperature threshold is reached, the digital interface will send a HIGH signal turning on the LED on the Arduino (pin 13). Turn the potentiometer clock-wise to increase the detection threshold and counter-clockwise to decrease it.

The analog interface returns a numeric value that depends on the temperature and the potentiometer's position. Since analog output pin is directly connected to the potentiometer it isn't possible to use the Steinhart-Hart equation to calculate the temperature as as we did with the KY-013, we can only use this value to measure relative changes in temperature.

int led = 13; // define the LED pin
int digitalPin = 2; // KY-028 digital interface
int analogPin = A0; // KY-028 analog interface
int digitalVal; // digital readings
int analogVal; //analog readings

void setup()
{
  pinMode(led, OUTPUT);
  pinMode(digitalPin, INPUT);
  //pinMode(analogPin, OUTPUT);
  Serial.begin(9600);
}

void loop()
{
  // Read the digital interface
  digitalVal = digitalRead(digitalPin); 
  if(digitalVal == HIGH) // if temperature threshold reached
  {
    digitalWrite(led, HIGH); // turn ON Arduino's LED
  }
  else
  {
    digitalWrite(led, LOW); // turn OFF Arduino's LED
  }

  // Read the analog interface
  analogVal = analogRead(analogPin); 
  Serial.println(analogVal); // print analog value to serial

  delay(100);
}

• Fritzing Part: KY-028 Digital Temperature Sensor Module.
• LM393 comparator datasheet.
• 3296W-104 trimmer datasheet.