Temperature Controlled Servo

Projects General Guidance
1

Hi all,

I am very new to Arduino. I recently bought the Beginner Kit for Arduino from DFRobot (SKU:DFR0100) and am trying to code a servo to rotate based on temperature. Essentially I would like the servo to be at 179 degrees when under 25 celsius and at 0 degrees when it is over 25 celsius. However my code is sadly not working. I don't have a good understanding of code, so please explain as much as you can!

#include <Servo.h>
Servo myservo; // create servo object to control a servo

unsigned long tepTimer ;
int threshold = 25; // Threshold for temperature
int servocold = 0; // Angle in which servo will go to
int servohot = 179; // Angle in which servo will go to

void setup(){
Serial.begin(9600);
myservo.attach(9); // attaches the servo on pin 9 to the servo object
}

void loop(){
int val;
double data;
val=analogRead(0);
data = (double) val * (5/10.24); // convert the voltage to temperture

if(data < threshold){ // If the temperture is over 27 degree, buzzer will alarm.
myservo.write(servocold);
}
if else (data > threshold); // If temperature is above the threshold, activate sequence
{
myservo.write(servohot);
}
if(millis() - tepTimer > 500){ // output the temperture value per 500ms
tepTimer = millis();
Serial.print("temperature: ");
Serial.print(data);
Serial.println("C");
}
}

I apologize in advance if it's a complete mess but I really need help!

2

Your code will not compile because of this line:

if else (data > threshold); // If temperature is above the threshold, activate sequence

Read about the if else syntax here.

In the future, if the code won't compile say so and post the error message. Please read the "how to use the forum" stickies to see how to properly format and post code and errors.

3

And even if you get the else right, it doesn't have a semicolon

4

The '?' operator is handy if you are selecting between two alternative values. In place of:

    if(data < threshold){        // If the temperture is over 27 degree, buzzer will alarm.  
         myservo.write(servocold);
                }   
if else (data > threshold); // If temperature is above the threshold, activate sequence
  {
      myservo.write(servohot);
    }

try

    myservo.write((data < threshold) ? servocold : servohot);