Stepper Motor and Serial.print() Wont work in the same sketch

Projects Programming
1

I am currently working on an arduino project where i'm using two ds18b20 Temp Sensors and a Nema 17 Stepper motor in one single sketch. So i have made a sketch for the ds18b20 Temp Sensors and another one for the Nema 17 Stepper motor and both works perfectly! However, When i tried to combine them in one single sketch, the nema 17 won't run anymore! After a bit of brainstorming i figure out that i am using Delay() and Delaymicroseconds() which they block the arduino from receiving any interrupt that's why i moved on to the micros() trying the arduino multitasking however i got the same problem happening every time. Then i went to a debug mode in order to figure out which command is blocking the stepper motor from running and i discovered that the Serial.print() and Serial.println() are slowing down the motor. PS: i am using a TB6560 Driver and a 1/8 step mode. and here are the sketch:

#include <OneWire.h>
#include <DallasTemperature.h>

#define ONE_WIRE_BUS 2

OneWire oneWire(ONE_WIRE_BUS);

DallasTemperature sensors(&oneWire);

float Celsius1 = 0;
float Celsius2 = 0;

const int SensorDuration = 500;
unsigned long TempcurrentMillis = 0;
unsigned long TemppreviousLedMillis = 0;
const int stepPin = 9;
const int dirPin = 8;
int motor = 3;
int msg;


const int offDuration = 150;
const int interval = 50;
unsigned long currentMillis = 0;
unsigned long previousLedMillis = 0;
byte targetLedState = HIGH;

void setup() {
  sensors.begin();
  // Sets the two pins as Outputs
  Serial.begin(9600);
  pinMode(stepPin, OUTPUT);
  pinMode(dirPin, OUTPUT);
  pinMode(motor, OUTPUT);
  digitalWrite(motor, LOW);

  digitalWrite(dirPin, HIGH);
}
void loop() {
  currentMillis = micros();
  TempcurrentMillis = micros();
  GetTemp();
  RunMotor();
}
void RunMotor() {
  if (targetLedState == LOW) {
    if ((unsigned long) currentMillis - previousLedMillis >= interval) {
      targetLedState = HIGH;
      digitalWrite(stepPin, HIGH);
      previousLedMillis += interval;

    }
  }
  else {

    if ((unsigned long) currentMillis - previousLedMillis >= offDuration) {
      targetLedState = LOW;
      digitalWrite(stepPin, LOW);

      previousLedMillis += offDuration;

    }
  }
}
void GetTemp() {
  if ((unsigned long) TempcurrentMillis - TemppreviousLedMillis >= SensorDuration) {
    targetLedState = HIGH;
    sensors.requestTemperatures();

    Celsius1 = sensors.getTempCByIndex(0);
    Celsius2 = sensors.getTempCByIndex(1);
    Serial.print("T");
    Serial.println(Celsius1);
    Serial.print("H");
    Serial.println(Celsius2);
    TemppreviousLedMillis += SensorDuration;

  }
}
2

You are doing quite a lot in the 50 microsecond interval defined in your code.
Maybe you should use a hardware timer ( say timer1 ) to control the step pin with the desired frequency and duty cycle.

This construct will give erratic behaviour if it is not executed exactly at 50 uS intervals

   const int interval = 50;
   . . .
   currentMillis = micros();
   . . .
   . . . 
    if ((unsigned long) currentMillis - previousLedMillis >= interval) {
      targetLedState = HIGH;
      digitalWrite(stepPin, HIGH);
      previousLedMillis += interval;

    }

Instead of:

previousLedMillis += interval;

More accurate would be the following to avoid a cumulative error:

previousLedMillis = micros();
3

vivoilpazzo:
However, When i tried to combine them in one single sketch, the nema 17 won't run anymore!

I don't have any personal experience of them but from reading other Threads it seems that the library code to read the Dallas sensors can be very slow. I think this is due to a poorly designed library which waits for the measurement rather than initiating a measurement and then coming back later for the result.

You could try temporarily disabling the calls to the sensor to see what happens.

Also look at how the stepper is controlled in the second example in this Simple Stepper Code. Note how the pulse duration is very short - that makes it easier to accommodate other stuff in the interval between pulses.

...R
Stepper Motor Basics

4

I have tried everything :confused: and i think i am going to use an arduino to arduino TX/RX communication instead because as i can see DallasTemperature::request Temperatures() is blocking the stepper rotation!

5

vivoilpazzo:
because as i can see DallasTemperature::request Temperatures() is blocking the stepper rotation!

You could write your own code to read the temperature without blocking.

...R

6

I went for a I2C arduino to arduino protocol to overcome this issue!