How do I power eight 5v 28BYJ-48 - ULN2003 ?

Using Arduino Motors, Mechanics, Power and CNC
#1

Hello,

I have connected 8 5v 28BYJ-48 stepper motors to an Arduino Mega 2560. I am using a separate 5v power supply for the motors and the Arduino is connected to the computer via a USB cable . The motors turn smoothly to begin with but then they begin to stall/stutter and the LED's on the driver boards flicker.

I tried again but with only 4 motors and these ran smoothly. I have attached a rough schematic of how everything is connected and code I am using below.

Would you say I need a bigger power supply?
Many thanks.

#include <AccelStepper.h>


// Define step constants
//#define FULLSTEP 4
#define HALFSTEP 8

// Define Motor Pins (2 Motors used)

#define motorPin1  22     // Blue   - 28BYJ48 pin 1
#define motorPin2  23    // Pink   - 28BYJ48 pin 2
#define motorPin3  24    // Yellow - 28BYJ48 pin 3
#define motorPin4  25    // Orange - 28BYJ48 pin 4
                        
                        
#define motorPin5  26     // Blue   - 28BYJ48 pin 1
#define motorPin6  27    // Pink   - 28BYJ48 pin 2
#define motorPin7  28     // Yellow - 28BYJ48 pin 3
#define motorPin8  29    // Orange - 28BYJ48 pin 4

#define motorPin9  30     // Blue   - 28BYJ48 pin 1
#define motorPin10 31    // Pink   - 28BYJ48 pin 2
#define motorPin11 32     // Yellow - 28BYJ48 pin 3
#define motorPin12 33    // Orange - 28BYJ48 pin 4

#define motorPin13 34     // Blue   - 28BYJ48 pin 1
#define motorPin14 35   // Pink   - 28BYJ48 pin 2
#define motorPin15 36   // Yellow - 28BYJ48 pin 3
#define motorPin16 37  // Orange - 28BYJ48 pin 4

#define motorPin17 38     // Blue   - 28BYJ48 pin 1
#define motorPin18 39   // Pink   - 28BYJ48 pin 2
#define motorPin19 40   // Yellow - 28BYJ48 pin 3
#define motorPin20 41  // Orange - 28BYJ48 pin 4

#define motorPin21 42     // Blue   - 28BYJ48 pin 1
#define motorPin22 43   // Pink   - 28BYJ48 pin 2
#define motorPin23 44   // Yellow - 28BYJ48 pin 3
#define motorPin24 45  // Orange - 28BYJ48 pin 4

#define motorPin25 46     // Blue   - 28BYJ48 pin 1
#define motorPin26 47   // Pink   - 28BYJ48 pin 2
#define motorPin27 48   // Yellow - 28BYJ48 pin 3
#define motorPin28 49  // Orange - 28BYJ48 pin 4


#define motorPin29 50     // Blue   - 28BYJ48 pin 1
#define motorPin30 51   // Pink   - 28BYJ48 pin 2
#define motorPin31 52   // Yellow - 28BYJ48 pin 3
#define motorPin32 53  // Orange - 28BYJ48 pin 4


// Define two motor objects
// The sequence 1-3-2-4 is required for proper sequencing of 28BYJ48
AccelStepper stepper1(HALFSTEP, motorPin1, motorPin3, motorPin2, motorPin4);
AccelStepper stepper2(HALFSTEP, motorPin5, motorPin7, motorPin6, motorPin8);
AccelStepper stepper3(HALFSTEP, motorPin9, motorPin11, motorPin10, motorPin12);
AccelStepper stepper4(HALFSTEP, motorPin13, motorPin15, motorPin14, motorPin16);
AccelStepper stepper5(HALFSTEP, motorPin17, motorPin19, motorPin18, motorPin20);
AccelStepper stepper6(HALFSTEP, motorPin21, motorPin23, motorPin22, motorPin24);
AccelStepper stepper7(HALFSTEP, motorPin25, motorPin27, motorPin26, motorPin28);
AccelStepper stepper8(HALFSTEP, motorPin29, motorPin31, motorPin30, motorPin32);
void setup() {
  // put your setup code here, to run once:
stepper1.setMaxSpeed(1000.0);
  stepper1.setAcceleration(100.0);
  stepper1.setSpeed(50);
  stepper1.moveTo(4072);  
  
  // 1 revolution Motor 2 CCW
  stepper2.setMaxSpeed(1000.0);
  stepper2.setAcceleration(100.0);
  stepper2.setSpeed(50);
  stepper2.moveTo(4072); 
  
  stepper3.setMaxSpeed(1000);
  stepper3.setAcceleration(100.0);
  stepper3.setSpeed(50);
  stepper3.moveTo(4072); 

 stepper4.setMaxSpeed(1000.0);
  stepper4.setAcceleration(100.0);
  stepper4.setSpeed(50);
  stepper4.moveTo(4072); 

   stepper5.setMaxSpeed(1000.0);
   stepper5.setAcceleration(100.0);
   stepper5.setSpeed(50);
   stepper5.moveTo(4072); 

   stepper6.setMaxSpeed(1000.0);
   stepper6.setAcceleration(100.0);
   stepper6.setSpeed(50);
   stepper6.moveTo(4072); 

   stepper7.setMaxSpeed(1000.0);
   stepper7.setAcceleration(100.0);
   stepper7.setSpeed(50);
   stepper7.moveTo(4072); 

   stepper8.setMaxSpeed(1000.0);
   stepper8.setAcceleration(100.0);
   stepper8.setSpeed(50);
   stepper8.moveTo(4072); 
}

void loop() {

stepper1.run();
stepper2.run();
stepper3.run();
stepper4.run();
stepper5.run();
stepper6.run();
stepper7.run();  
stepper8.run(); 


  // put your main code here, to run repeatedly:

}

8 Stepper Motors11.jpg
8 Stepper Motors11.jpg4433×3353 854 KB

8 Stepper Motors11.jpg
8 Stepper Motors11.jpg4433×3353 854 KB

#2

I see no attached schematic, you aren't allowed to attach in your first post I believe as an spam-block precaution, so
try again?

Also where is the data on your hardware? Power supply in particular.

#3

If the supply can provide enough current for the steppers (about 250mA each), then I expect that the Mega can't keep up with the computations.
Play a bit with max speed and acceleration values.
Leo..

#4

Do you have the power supply Gnd connected to the Arduino Gnd?

I did similar to you, with 7 motors and a supply with motors controlled by Atmega1284P and Stepper.h library, with motors just going back and forth.
Video of it working
(http://“http://“7-motor display - YouTube””)]https://www.youtube.com/watch?v=5-9pqTQP_SQ

You could try my code and see if things are working ok. This is for 17 motors on a mega, shorten it to just 6 if you want.
I was testing for speed impact to have so many, but only had 1 28BYJ-48 motor hooked when I last ran this. millis() was being used to see how long one 360 turn took. It actually measures one full circle and back, I just did the math with calculator to see how long it was taking (7.1 seconds I think).

#include <Stepper.h> //include the function library, standard Arduino library
#define STEPS 64 // 64 steps per rev // hardware dependent
byte x;
unsigned long startTime;
unsigned long endTime;
unsigned long elapsedTime;


int speed[] = {
  270, 270, 270, 270, 270, 270, 270, 270, 270, 270, 270, 270, 270, 270, 270, 270,
}; // speed to move motor, 540 seems to be max for these motors


int numSteps[] = {
  2048, 2500, 2500, 2500, 2500, 2500, 2500, 2500, 2500, 2500, 2500, 2500, 2500, 2500, 2500, 2500,
}; // steps to move in total = distance


int countSteps[] = {
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
}; // track how much moved


byte stepsDir[] =  {
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
}; // counterclockwise or clockwise, 0 or 1


int stepSize[] = {
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
}; // how big of a step, 2,4,8,10; 16 max to look smooth


// delayed starting times for movement effect
int delayStart[] = {0, 1500, 2500, 3500, 4500, 5500, 6500, 7500, 8500, 9500, 10500, 11500, 12500, 13500, 14500, 15500,};


Stepper steppers[] = {
  {STEPS, 5, 3, 4, 2},//create the stepper0  <<< Declare the pins to use, Order here is important
  {STEPS, 6, 8, 7, 9}, //create the stepper1  <<< Order here is important
  {STEPS, 10, 12, 11, 13}, //create the stepper2  <<< Order here is important
  {STEPS, 17, 15, 16, 14}, //create the stepper3  <<< Order here is important
  {STEPS, 21, 19, 20, 18}, //create the stepper4  <<< Order here is important
  {STEPS, 22, 24, 23, 25}, //create the stepper5  <<< Order here is important
  {STEPS, 29, 27, 28, 26}, //create the stepper5  <<< Order here is important
  {STEPS, 33, 31, 32, 30}, //create the stepper7  <<< Order here is important
  {STEPS, 37, 35, 36, 34}, //create the stepper8  <<< Order here is important
  {STEPS, 41, 39, 40, 38}, //create the stepper9  <<< Order here is important
  {STEPS, 45, 43, 44, 42}, //create the stepper10  <<< Order here is important
  {STEPS, 49, 47, 48, 46}, //create the stepper11  <<< Order here is important
  {STEPS, 53, 51, 52, 50}, //create the stepper12  <<< Order here is important
  {STEPS, 57, 55, 56, 54}, //create the stepper13  <<< Order here is important
  {STEPS, 61, 59, 60, 58}, //create the stepper14  <<< Order here is important
  {STEPS, 65, 63, 64, 62},  //create the stepper15  <<< Order here is important
};


void setup()
{
  Serial.begin(115200); // initialize serial communication:
  for (x = 0; x < 16; x = x + 1) {
    //  steppers[i].whatever();  // example of using loop with this command
    steppers[x].setSpeed(speed[x]);
  }
}
void loop() {
  for (x = 0; x < 16; x = x + 1) {
    if (millis() > delayStart[x]) {
      // Motor x
      if (stepsDir[x] == 0) {
        countSteps[x] = countSteps[x] + stepSize[x];
        if (countSteps[0] == 2048){
          startTime = millis();
          Serial.println (startTime);
        }
        if (countSteps[x] >= numSteps[x]) {
          countSteps[x] = numSteps[x];
          stepsDir[x] = 1;
        }
      }


      if (stepsDir[x] == 1) {
        countSteps[x] = countSteps[x] - stepSize[x];
        if (countSteps[x] <= 0) {
          countSteps[x] = 0;
          stepsDir[x] = 0;
        }
      }


      if (stepsDir[x] == 0) {
        steppers[x].step(stepSize[x]); //move one direction
      }
      if (stepsDir[x] == 1) {
        steppers[x].step(-stepSize[x]); //move the other direction
      }
    }
  }
}
#5