Problem getting the correct speed on my NEMA17+A4489+potentiometer project

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Seems to be a problem with the map function - I never saw really low values. I tried, and without Serial.print it got faster, but not as fast as expected. If you omit the mapping ist goes the other way round ( regarding the potentiometer ), but much faster.

There is an example 'minimumStepper' which can easily be extended to your potentiometer variant:

/* ====== minimumStepper =======================================
 *  Bare minimum to get a stepper with step/dir driver turning
 */
#include <MobaTools.h>
// Stepper connections - Please adapt to your own needs.
const byte stepPin = 3;
const byte dirPin = 2;

const int stepsPerRev = 200;    // Steps per revolution - may need to be adjusted

MoToStepper stepper1( stepsPerRev, STEPDIR );  // create a stepper instance

void setup() {
  Serial.begin(9600);
  stepper1.attach( stepPin, dirPin );
  stepper1.setSpeed( 300 );              // 30 rev/min (if stepsPerRev is set correctly)
  stepper1.setRampLen( stepsPerRev / 2); // Ramp length is 1/2 revolution
  stepper1.rotate(1);                    // start turning, 1=vorward, -1=backwards                    
}

void loop() {
  int pot = analogRead(A0);
  int speed=map(pot, 0, 1023, 10,7500); // 1 ... 750 RPM
  Serial.println(speed);
  stepper1.setSpeed( speed );
  delay(100);
}
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