Using ArduinoThread with delay

Projects Programming
1

Hello.

What I would need to do is to run a stepper motor while reading an arduino analog sensors. This fills in a bigger project, so I'm writing only the code related to this part.

Before I needed to read the sensor, I was driving the motor by switching the stepping pin from HIGH to LOW with a delay (easy way to drive a stepper). As soon as I had to read it with a different sampling frequency, I switched to use ArduinoThread library, but I immediately faced a problem.

This is precisely what it should be done:

  • Arduino gets a signal from a computer
  • Arduino start reading the analog sensor with a sampling rate of 1 kHz
  • While reading, arduino must generate few stepper pulses of 300 ms, 5 seconds distant, and store the starting time
  • Do some analysis

I spare you the part of the signal acquisition and analysis.

Before even try to make long stepper pulses, I've realised that firstly I need to know how to run a single step while keeping on reading the pin. I found it hard because the use of delay inside the thread cause the others to stop, so I would need two threads for the stepper and one for the sensor. The first two should have the same interval (5 seconds), but shifted of X microseconds to have the desired speed.

How can I keep the same interval but shift one thread in time?

#include <Thread.h>
#include <ThreadController.h>

Thread thread1 = Thread();
Thread thread2 = Thread();
Thread thread3 = Thread();
ThreadController control = ThreadController();

void thread1Callback()
{
  digitalWrite(2,HIGH);
}

void thread2Callback()
{
  digitalWrite(2,LOW);
}

void thread3Callback()
{
  //read sensor and do things
  return;
}

void setup()
{  
  pinMode(2,OUTPUT); 

  thread1.onRun(thread1Callback);
  thread1.setInterval(3000);
  thread2.onRun(thread2Callback); //??
  thread2.setInterval(3000);
  thread3.onRun(thread3Callback);
  thread3.setInterval(1);

  control.add(&thread1);
  control.add(&thread2);
  control.add(&thread3);
}

void loop()
{
  control.run();
}
2

There's a fairly small population of people that answer questions in this forum. Of those, I suspect that the number that are familiar with your thread library is tiny.

So you may find someone to help, but you're likely better off coding up your solution using millis. Look at the example sketch for blink without delay to get you started.

3

Thanks for tip, I succeed at writing the right code!

void startSynchro(int motor_ind, int pulseT, long stepperdelay, int pulses, long interdelay)
{
  unsigned long previousMicrosRead = 0;
  unsigned long previousMicrosPulse = 0;
  unsigned long previousMicrosStepperPulse = 0;
  short runsToStop = pulses;
  bool stepperUp = true;
  
  while (runsToStop > 0)
  {
    unsigned long currentMicros = micros(); //maybe better long long for long acquisitions
    
    if (currentMicros - previousMicrosRead >= 1000)
    {
      previousMicrosRead = currentMicros;
      analogRead(SINCHRO_PIN);
    }

    if (currentMicros - previousMicrosPulse >= interdelay)
    {
      previousMicrosPulse = currentMicros;
      triggerT[10 - runsToStop] = previousMicrosPulse;
      for(unsigned long tStart = millis();  (millis()-tStart) < pulseT;)
      {
        currentMicros = micros();
        if (currentMicros - previousMicrosRead > 1000)
        {
          previousMicrosRead = currentMicros;
          analogRead(SINCHRO_PIN);
        }       
        if (currentMicros - previousMicrosStepperPulse >= stepperdelay)
        {
          previousMicrosStepperPulse = currentMicros;
          if (stepperUp)
          {
            digitalWrite(motor_ind + 1,HIGH);
          }
          else
          {
            digitalWrite(motor_ind + 1,LOW);
          }
          stepperUp = !stepperUp;
        }
      }
      stepperUp = LOW;
      runsToStop -= 1;
    }
  }
}