#include <Servo.h>

Servo servo1;
long num;
int Speed = 20;

int potmeter = A0;

void setup()
{
  servo1.attach(9);
  Serial.begin(9600);
  pinMode(8, OUTPUT);
}

void loop()
{
  int sensorwaarde = analogRead(potmeter);
  while(Serial.available()>0)
  {
  //sensorwaarde= map(sensorwaarde, 0, 1023, 0, 40);
  //Speed= Serial.parseInt();
  }
  int Speed =(int)( sensorwaarde * 40.0/1024.0);
  num = 90 + (Speed - 20) * 2;
  Serial.print("num = ");
  Serial.print(num);
  Serial.print("   Speed = ");
  Serial.print(Speed);
  Serial.print("   Pot = ");
  Serial.println(sensorwaarde);
  servo1.write(num);
  delay(15);
}