Including push-button to thermometer

Projects General Guidance
3

rw950431:
The code you posted doesnt appear to have any pushbutton functionality. It would be useful to include the code you had tried..

The basic scheme is pretty simple :

// this doesnt take into account switch bounce

current_button=digitalRead(BUTTON_PIN);

if (current_button!=previous_button) {
  if (current_button==HIGH) {
    // button is pressed
    if (sensor_state==HIGH) {
        // was HIGH, going low so turn off sensor, LEDS etc

sensor_state = LOW;
    } else {
        // was LOW, going high so turn on sensor, LEDS ect

sensor_state = HIGH;
    };
  // update button state so we dont trigger until it changes again.
  previous_button=current_button;   
};





But you may need to account for [Switch Bounce](https://www.arduino.cc/en/Tutorial/Debounce)

Hey rw and thank for the answer!

Here is the code with push-button function included

// set variables
int sensorVal;
int heartBeat = 0;
int blinkingMIN = 0;
int blinkingMAX = 0;

unsigned long timer1;
unsigned long timer2;
unsigned long timer3;
unsigned long timer4;

const int sensorPin = A0;                 // the number of pin for the temperature sensor (analog input)
const float roomTemp = 21.0;              // room temperature in Celsius
float temperature;

int button = 11;
int tempSensorEnabled = 0;
boolean previousButtonState = LOW;
boolean buttonState = LOW;

void setup() {

  pinMode(button, INPUT);
  pinMode(sensorPin, OUTPUT);
  
  // open a serial connection to display values
  Serial.begin(9600);
  // set the LED pins as outputs
  pinMode(13, OUTPUT);
  for (int pinNumber = 2; pinNumber < 8; pinNumber++) {
    pinMode(pinNumber, OUTPUT);
    digitalWrite(pinNumber, LOW);
  }

  //LED test at startup
  digitalWrite(2,HIGH);
  delay(100);
  digitalWrite(3,HIGH);
  delay(100);
  digitalWrite(4,HIGH);
  delay(100);
  digitalWrite(5,HIGH);
  delay(100);
  digitalWrite(6,HIGH);
  delay(100);
  digitalWrite(7,HIGH);
  delay(500);
  digitalWrite(7,LOW);
  digitalWrite(6,LOW);
  digitalWrite(5,LOW);
  digitalWrite(4,LOW);
  digitalWrite(3,LOW);
  digitalWrite(2,LOW);
  delay(500);

}
void loop() {

  buttonState = digitalRead(button);

  if(previousButtonState != buttonState && buttonState == HIGH){
    tempSensorEnabled = !tempSensorEnabled;
    }
  if(tempSensorEnabled == 1){
    digitalWrite(sensorPin,HIGH);
    }
  else{
    digitalWrite(sensorPin,LOW);
    }
  previousButtonState = buttonState;

  // Make the LED blink
  if (millis() - timer1 > 500){
    heartBeat = !heartBeat;
    digitalWrite (13, heartBeat);
    timer1 = millis();
  }

  // update sensor value at 1Hz and print the values to serial monitor
  if(millis() - timer2 > 1000) {
    sensorVal = analogRead(sensorPin);
    temperature = (5.0 * sensorVal * 100.0) / 1024;
    Serial.print("degrees C:  ");
    Serial.println(temperature);
    timer2 = millis();
  }
  
  // if the current temperature is lower than the roomTemp: turn off all LEDs and blink the LED in pin 2 -> temperature under minimum value
  if (temperature < roomTemp + 2) {
    digitalWrite(3, LOW);
    digitalWrite(4, LOW);
    digitalWrite(5, LOW);
    digitalWrite(6, LOW);
    digitalWrite(7, LOW);

  // Make the LED blink
  if (millis() - timer3 > 500){
    blinkingMIN = !blinkingMIN;
    digitalWrite (2, blinkingMIN);
    timer3 = millis();  
    }
  }
  
  // if the temperature rises 2-3 degrees: turn an LED on
  else if (temperature >= roomTemp + 2 && temperature < roomTemp + 3) {
    digitalWrite(2, HIGH);
    digitalWrite(4, LOW);
    digitalWrite(5, LOW);
    digitalWrite(6, LOW);
    digitalWrite(7, LOW);
  } 
  
  // if the temperature rises 3-4 degrees: turn a second LED on
  else if (temperature >= roomTemp + 3 && temperature < roomTemp + 4) {
    digitalWrite(2, HIGH);
    digitalWrite(3, HIGH);
    digitalWrite(4, LOW);
    digitalWrite(5, LOW);
    digitalWrite(3, LOW);
    digitalWrite(6, LOW);
    digitalWrite(7, LOW);
  } 
  
  // if the temperature rises 4-5 degrees: turn a third LED on
  else if (temperature >= roomTemp + 4 && temperature < roomTemp + 5) {
    digitalWrite(2, HIGH);
    digitalWrite(3, HIGH);
    digitalWrite(4, HIGH);
    digitalWrite(5, LOW);
    digitalWrite(6, LOW);
    digitalWrite(7, LOW);
  } 
  
  // if the temperature rises 5-6 degrees: turn a fourth LED on
  else if (temperature >= roomTemp + 5 && temperature < roomTemp + 6) {
    digitalWrite(2, HIGH);
    digitalWrite(3, HIGH);
    digitalWrite(4, HIGH);
    digitalWrite(5, HIGH);
    digitalWrite(6, LOW);
    digitalWrite(7, LOW);
  } 
  
  // if the temperature rises 6-7 degrees, turn a fifth LED on
  else if (temperature >= roomTemp + 6 && temperature < roomTemp + 7) {
    digitalWrite(2, HIGH);
    digitalWrite(3, HIGH);
    digitalWrite(4, HIGH);
    digitalWrite(5, HIGH);
    digitalWrite(6, HIGH);
    digitalWrite(7, LOW);
  } 
  
  // if the temperature goes 7 degrees over the roomTemp: turn on all LEDs and blink the led in pin 7 -> maximum value has been crossed
  else if (temperature >= roomTemp + 7) {
    digitalWrite(2, HIGH);
    digitalWrite(3, HIGH);
    digitalWrite(4, HIGH);
    digitalWrite(5, HIGH);
    digitalWrite(6, HIGH);
 
   // Make the LED blink
   if (millis() - timer4 > 500) {
     blinkingMAX = !blinkingMAX;
     digitalWrite (7, blinkingMAX);
     timer4 = millis();  
   }
  }
}

Problem is that when the button is not pressed, serial monitor reads the sensor value for 15 degrees C. When the button is pressed again the value is 499 degrees C until I press the button again and it jumps back to 15.

Any idea why that happens?