Strange stepper motor

Forum 2005-2010 (read only) Hardware Interfacing
1

Hi, I have connected up a stepper motor using a darlington array and driving it with an Arduino. However, the stepper seems to just jump back and forth, even though I have tried almost every possible combination, different voltages etc. If it's wired how I think it goes, you can help it spin and it will go freely, but it wont spin by itself, just sit there rocking back and forth.

Any idea's on things to try? The stepper has 6 wires, I assume 2 are common.

Cheers,
Dan

2

I am just using a transistor array package.

I am powering the stepper from an external bench power supply.

I'm using the basic stepper code:

int motorPin1 = 7;
int motorPin2 = 6;
int motorPin3 = 5;
int motorPin4 = 4;
int delayTime = 100;

void setup() {
  pinMode(motorPin1, OUTPUT);
  pinMode(motorPin2, OUTPUT);
  pinMode(motorPin3, OUTPUT);
  pinMode(motorPin4, OUTPUT);
}

void loop() {
  digitalWrite(motorPin1, HIGH);
  digitalWrite(motorPin2, LOW);
  digitalWrite(motorPin3, LOW);
  digitalWrite(motorPin4, LOW);
  delay(delayTime);
  digitalWrite(motorPin1, LOW);
  digitalWrite(motorPin2, HIGH);
  digitalWrite(motorPin3, LOW);
  digitalWrite(motorPin4, LOW);
  delay(delayTime);
  digitalWrite(motorPin1, LOW);
  digitalWrite(motorPin2, LOW);
  digitalWrite(motorPin3, HIGH);
  digitalWrite(motorPin4, LOW);
  delay(delayTime);
  digitalWrite(motorPin1, LOW);
  digitalWrite(motorPin2, LOW);
  digitalWrite(motorPin3, LOW);
  digitalWrite(motorPin4, HIGH);
  delay(delayTime);
}

Cheers,
Dan

3

These steppers originally ran on 11V, they are getting that.

I looked at the traces on the old board they used to run off, and found the 2 common wires.

I would measure the resistance, but the battery clamp in my DMM is dead.

4

I just tried all 24 different wire combinations, and it continues to rock back and forth.

What would the 2 common wires be for? If I disconnect one, I can help it move around and the coils are in the right order, but once again, it wont move itself :(.

5

It's only a small motor, and as with almost all things made in China, I can't find barely any information about it.

I'm 99% sure I have the right wires and wired it up properly, so I'm confused as to why it's not working.

6

I've tried anywhere from 1000 to 1, doesn't make any difference except the speed of how fast it moves back and forth.

7

Try sequences like:

HIGH
LOW
HIGH
LOW
delay

LOW
HIGH
HIGH
LOW
delay

LOW
HIGH
LOW
HIGH
delay

etc.

Only energizing one winding at a time is a low-torque method that could cause oscillation as you describe depending on torque.

--
The Gadget Shield: accelerometer, RGB LED, IR transmit/receive, light sensor, potentiometers, pushbuttons

8

Doing that just makes it stay still. This is really weird :frowning:

9

Aha, it works! :smiley:

I had 1 of the common wires, but the other one was different. It now spins, but it has barely any torque before it stalls.

Any way I can increase the torque?

Cheers,
Dan

10

Make sure you have two phases on at a time, as I suggested.

Use more voltage?

Use MOSFET's rather than a transistor array, they will drop less voltage.

--
The Quick Shield: breakout all 28 pins to quick-connect terminals

11

When I try what you said the motor just locks up completely?