View difference between Paste ID: iLSDdZz8 and Y7uN7zHD

 #include <math.h>
 
 int ledPin=13;
 int potPin=A0;
 
 void setup()
 {
   Serial.begin(38400);
   pinMode(potPin, INPUT);
   pinMode(ledPin, OUTPUT);
 }
 
 void loop()
 {
   int potPin=A0;
   int potVal1=analogRead(potPin);
   delay(640);
   int potVal2=analogRead(potPin);
 
-  int rSpeed=potVal1-potVal2;
+  int rSpeed=potVal2-potVal1;
 
   Serial.print("Velocity over last 690ms: ");
   Serial.println(rSpeed);
   Serial.print("Current Pot Position: ");
   Serial.println(potVal2);
 
   isIncreasing(potVal1, potVal2, ledPin);
 }
 
   void isIncreasing(int potVal1, int potVal2, int ledPin)
   {
     if (potVal2<potVal1)
     {
       boolean isIncreasing=true;
       digitalWrite(ledPin, HIGH);
     }
     else
     {
       boolean isIncreasing=false;
       digitalWrite(ledPin, LOW);
     }
   }