如何用半步循环步进电机

Question

I have four digital pins stored in the array inPins[4] which power on different phases of my stepper motor. The wave function was simple enough, because there is never more than one phase on. My wave function looks like so:

void waveClockwise()
{
  for (int i = 0; i < 4; i++)
  {
    digitalWrite(inPins[i], HIGH);
    delay(delayTime);
    digitalWrite(inPins[i], LOW);
  }
  
  return;
}

This ^ is called repetitively in the loop. In implementing a halfStep function however, I am having a hard time wrapping my head around how this could be done in for loop.

For the halfStep, the sequence goes:

1. in1: ON
2. in2: ON
3. in1: OFF
4. in3: ON
5. in2: OFF

... and so on as it half steps around the phases. I got it done with the following code, but am just curious how I could do this in a loop. Any tips, or ideas?

void halfStepClockwise()
{
  digitalWrite(inPins[0], HIGH);
  delay(delayTime);
  digitalWrite(inPins[1], HIGH);
  delay(delayTime);
  digitalWrite(inPins[0], LOW);
  delay(delayTime);
  digitalWrite(inPins[2], HIGH);
  delay(delayTime);
  digitalWrite(inPins[1], LOW);
  delay(delayTime);
  digitalWrite(inPins[3], HIGH);
  delay(delayTime);
  digitalWrite(inPins[2], LOW);
  delay(delayTime);
  digitalWrite(inPins[0], HIGH);
  delay(delayTime);
  digitalWrite(inPins[3], LOW);
  delay(delayTime);
}

Answer 1

Put the indices of that inPins array and the polarities into their own arrays:

int indices[] = { 0, 1, 0, 2, 1, 3, 2, 0, 3 };
// Assuming HIGH and LOW are defined as ints
int polarities = { HIGH, HIGH, LOW, HIGH, LOW, HIGH, LOW, HIGH, LOW };
int size = sizeof(indices) / sizeof(int);

You can then:

for (int i = 0; i < size; i++)
{
    digitalWrite(inPins[indices[i]], polarities[i]);
    delay(delayTime);
}

Answer 2

Firstly, divide the sequence of pin handling to find some pattern:

void halfStepClockwise()
{
  digitalWrite(inPins[0], HIGH);
  delay(delayTime);

  digitalWrite(inPins[1], HIGH);
  delay(delayTime);
  digitalWrite(inPins[0], LOW);
  delay(delayTime);

  digitalWrite(inPins[2], HIGH);
  delay(delayTime);
  digitalWrite(inPins[1], LOW);
  delay(delayTime);

  digitalWrite(inPins[3], HIGH);
  delay(delayTime);
  digitalWrite(inPins[2], LOW);
  delay(delayTime);

  digitalWrite(inPins[0], HIGH);
  delay(delayTime);
  digitalWrite(inPins[3], LOW);
  delay(delayTime);
}

Except for the first block, the lines are turning pin n mod 4 high, then turning pin n-1 low.

Let's code this:

void halfStepClockwise()
{
  digitalWrite(inPins[0], HIGH);
  delay(delayTime);

  for (int i = 1; i <= 4; i++)
  {
    digitalWrite(inPins[i % 4], HIGH);
    delay(delayTime);
    digitalWrite(inPins[i - 1], LOW);
    delay(delayTime);
  }
}