Motor Unipolar ST28. What's wrong ?

Other Hardware Motors, Mechanics, Power and CNC
1

Hi.

I'm triing to mount a motor unipolar ST28 mingjong 12Vc 320mA with this conection :

And datasheet secuence to turn motor. But it don't turn. Someone knows what it's wrong ?

I'm triing this code too as a similiar conection motor too but motor don't move.

const int ledPin = 13;

const int motorPin1 = 8;   // Pin Orange
const int motorPin2 = 9;   // Pin Yellow
const int motorPin3 = 10;  // Pin Pink
const int motorPin4 = 11;  // Pin Blue
int delayTime = 500; // Delay que determina la velocidad de giro

void setup() {

   pinMode(ledPin, OUTPUT);
   // Configuración de los PIN-es como salida digital
   pinMode(motorPin1, OUTPUT); 
   pinMode(motorPin2, OUTPUT);
   pinMode(motorPin3, OUTPUT);
   pinMode(motorPin4, OUTPUT);

   // Los pongo todos a Cero
   digitalWrite(motorPin1, HIGH);
   digitalWrite(motorPin2, HIGH);
   digitalWrite(motorPin3, HIGH);
   digitalWrite(motorPin4, HIGH);
   delay(delayTime);
   
   // Los pongo todos a Cero
   digitalWrite(motorPin1, LOW);
   digitalWrite(motorPin2, LOW);
   digitalWrite(motorPin3, LOW);
   digitalWrite(motorPin4, LOW);
   delay(delayTime);
}

void blink() {
  digitalWrite(ledPin,HIGH);
  delay(10);
  digitalWrite(ledPin,LOW);
}


void loop() {
  
  digitalWrite(motorPin1, LOW); // Primer paso
  digitalWrite(motorPin2, LOW);
  digitalWrite(motorPin3, LOW);
  digitalWrite(motorPin4, HIGH);
  blink();
  delay(delayTime);
  
  digitalWrite(motorPin1, LOW); // Segundo paso
  digitalWrite(motorPin2, LOW);
  digitalWrite(motorPin3, HIGH);
  digitalWrite(motorPin4, HIGH);
  blink();
  delay(delayTime);
  
  digitalWrite(motorPin1, LOW); // Tercer paso
  digitalWrite(motorPin2, LOW);
  digitalWrite(motorPin3, HIGH);
  digitalWrite(motorPin4, LOW);
  blink();
  delay(delayTime);
  
  digitalWrite(motorPin1, LOW); // Cuarto paso
  digitalWrite(motorPin2, HIGH);
  digitalWrite(motorPin3, HIGH);
  digitalWrite(motorPin4, LOW); 
  blink();
  delay(delayTime); 
  
  digitalWrite(motorPin1, LOW); // Quinto paso
  digitalWrite(motorPin2, HIGH);
  digitalWrite(motorPin3, LOW);
  digitalWrite(motorPin4, LOW);
  blink();
  delay(delayTime);

  digitalWrite(motorPin1, HIGH); // Sexto paso
  digitalWrite(motorPin2, HIGH);
  digitalWrite(motorPin3, LOW);
  digitalWrite(motorPin4, LOW);
  blink();
  delay(delayTime);

  digitalWrite(motorPin1, HIGH); // Septimo paso
  digitalWrite(motorPin2, LOW);
  digitalWrite(motorPin3, LOW);
  digitalWrite(motorPin4, LOW);
  blink();
  delay(delayTime);

  digitalWrite(motorPin1, HIGH); // Octavo paso
  digitalWrite(motorPin2, LOW);
  digitalWrite(motorPin3, LOW);
  digitalWrite(motorPin4, HIGH);
  blink();
  delay(delayTime);
}

pd: Dip is an ULN2003A
diagram
and finally I connected motor to (550W) ATX power. (Yellow, Black)

2

What is the chip on the breadboard? What is the power supply for the motor? Schematic? Decoupling?

3

The chip on the breadboard is an ULN2003A and de power supply is an ATX. Conected at pin 12v and ground.

4

The red wire should be at the 12V.

Do you see or feel the motor become stiff and does it make a buzzing noise when you try and drive it?

If so you should slow down the speed you are trying to drive it and try swapping the coil motor wires around to get the sequence right.

5

You will also need to hookup pin 9 of the ULN2003 to de power (plus side of course) or you will blow out the drivers (which you may already have).

Pin 9 is the common return for the internal diodes. Google will ...