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Topic: 28BYJ-48 5-Volt Stepper (Read 87 times) previous topic - next topic

celem

Dec 31, 2011, 08:46 pm Last Edit: Dec 31, 2011, 10:44 pm by celem Reason: 1
FYI - below is some Arduino code that demonstrates bidirectional operation of a 28BYJ-48 5-Volt stepper motor. It does not use the Arduino library partly because I wanted to get a bit more hands-on with the stepper to learn its operation and partly because the library isn't designed for this type of stepper and the pin assignments need to flipped around to work. Plus, I don't think that the library correctly addresses the eight codes required for this stepper and, instead, uses only four codes. Anyway, this code works well for a functionality demo. The code is based on some general stepper code that I found on the web (I don't recall where) and modified for the  28BYJ-48 stepper. I have also attached a photo of the stepper and interface board that I am using - <$5 for both on eBay. I have also attached a schematic for the ULN2003 Driver Board.

Code: [Select]

// This Arduino example demonstrates bidirectional operation of a
// 28BYJ-48, which is readily available on eBay, using a ULN2003
// interface board to drive the stepper. The 28BYJ-48 motor is a 4-
// phase, 8-beat motor, geared down by a factor of 68. One bipolar
// winding is on motor pins 1 & 3 and the other on motor pins 2 & 4.
// Refer to the manufacturer's documentation of  Changzhou Fulling
// Motor Co., Ltd., among others.  The step angle is 5.625/64 and the
// operating Frequency is 100pps. Current draw is 92mA.  In this
// example, the speed and direction of the stepper motor is determined
// by adjusting a 1k-ohm potentiometer connected to Arduino pin A2.
// When the potentiometer is rotated fully counterclockwise, the motor
// will rotate at full counterclockwise speed. As the potentiometer is
// rotated clockwise, the motor will continue to slow down until is
// reaches its minimum speed at the the potentiometer's midpoint value .
// Once the potentiometer crosses its midpoint, the motor will reverse
// direction. As the potentiometer is rotated further clockwise, the speed  
// of the motor will increase until it reaches its full clockwise rotation
// speed when the potentiometer has been rotated fully clockwise.
////////////////////////////////////////////////

//declare variables for the motor pins
int motorPin1 = 8; // Blue   - 28BYJ48 pin 1
int motorPin2 = 9; // Pink   - 28BYJ48 pin 2
int motorPin3 = 10; // Yellow - 28BYJ48 pin 3
int motorPin4 = 11; // Orange - 28BYJ48 pin 4
                       // Red    - 28BYJ48 pin 5 (VCC)

int motorSpeed = 0;     //variable to set stepper speed
int potPin = 2; //potentiometer connected to A2
int potValue = 0; //variable to read A0 input


//////////////////////////////////////////////////////////////////////////////
void setup() {
 //declare the motor pins as outputs
 pinMode(motorPin1, OUTPUT);
 pinMode(motorPin2, OUTPUT);
 pinMode(motorPin3, OUTPUT);
 pinMode(motorPin4, OUTPUT);
 Serial.begin(9600);
}

//////////////////////////////////////////////////////////////////////////////
void loop(){

 potValue = analogRead(potPin);     // read the value of the potentiometer
 Serial.println(potValue);          // View full range from 0 - 1024 in Serial Monitor
 if (potValue < 535){               // if potentiometer reads 0 to 535 do this
   motorSpeed = (potValue/15 + 5);  //scale potValue to be useful for motor
   clockwise();                     //go to the ccw rotation function
 }
 else {                             //value of the potentiometer is 512 - 1024
   motorSpeed = ((1024-potValue)/15 + 5); //scale potValue for motor speed
   counterclockwise(); //go the the cw rotation function
 }
}

//////////////////////////////////////////////////////////////////////////////
//set pins to ULN2003 high in sequence from 1 to 4
//delay "motorSpeed" between each pin setting (to determine speed)

void counterclockwise (){
 // 1
 digitalWrite(motorPin1, HIGH);
 digitalWrite(motorPin2, LOW);
 digitalWrite(motorPin3, LOW);
 digitalWrite(motorPin4, LOW);
 delay(motorSpeed);
 // 2
 digitalWrite(motorPin1, HIGH);
 digitalWrite(motorPin2, HIGH);
 digitalWrite(motorPin3, LOW);
 digitalWrite(motorPin4, LOW);
 delay (motorSpeed);
 // 3
 digitalWrite(motorPin1, LOW);
 digitalWrite(motorPin2, HIGH);
 digitalWrite(motorPin3, LOW);
 digitalWrite(motorPin4, LOW);
 delay(motorSpeed);
 // 4
 digitalWrite(motorPin1, LOW);
 digitalWrite(motorPin2, HIGH);
 digitalWrite(motorPin3, HIGH);
 digitalWrite(motorPin4, LOW);
 delay(motorSpeed);
 // 5
 digitalWrite(motorPin1, LOW);
 digitalWrite(motorPin2, LOW);
 digitalWrite(motorPin3, HIGH);
 digitalWrite(motorPin4, LOW);
 delay(motorSpeed);
 // 6
 digitalWrite(motorPin1, LOW);
 digitalWrite(motorPin2, LOW);
 digitalWrite(motorPin3, HIGH);
 digitalWrite(motorPin4, HIGH);
 delay (motorSpeed);
 // 7
 digitalWrite(motorPin1, LOW);
 digitalWrite(motorPin2, LOW);
 digitalWrite(motorPin3, LOW);
 digitalWrite(motorPin4, HIGH);
 delay(motorSpeed);
 // 8
 digitalWrite(motorPin1, HIGH);
 digitalWrite(motorPin2, LOW);
 digitalWrite(motorPin3, LOW);
 digitalWrite(motorPin4, HIGH);
 delay(motorSpeed);
}

//////////////////////////////////////////////////////////////////////////////
//set pins to ULN2003 high in sequence from 4 to 1
//delay "motorSpeed" between each pin setting (to determine speed)

void clockwise(){
 // 1
 digitalWrite(motorPin4, HIGH);
 digitalWrite(motorPin3, LOW);
 digitalWrite(motorPin2, LOW);
 digitalWrite(motorPin1, LOW);
 delay(motorSpeed);
 // 2
 digitalWrite(motorPin4, HIGH);
 digitalWrite(motorPin3, HIGH);
 digitalWrite(motorPin2, LOW);
 digitalWrite(motorPin1, LOW);
 delay (motorSpeed);
 // 3
 digitalWrite(motorPin4, LOW);
 digitalWrite(motorPin3, HIGH);
 digitalWrite(motorPin2, LOW);
 digitalWrite(motorPin1, LOW);
 delay(motorSpeed);
 // 4
 digitalWrite(motorPin4, LOW);
 digitalWrite(motorPin3, HIGH);
 digitalWrite(motorPin2, HIGH);
 digitalWrite(motorPin1, LOW);
 delay(motorSpeed);
 // 5
 digitalWrite(motorPin4, LOW);
 digitalWrite(motorPin3, LOW);
 digitalWrite(motorPin2, HIGH);
 digitalWrite(motorPin1, LOW);
 delay(motorSpeed);
 // 6
 digitalWrite(motorPin4, LOW);
 digitalWrite(motorPin3, LOW);
 digitalWrite(motorPin2, HIGH);
 digitalWrite(motorPin1, HIGH);
 delay (motorSpeed);
 // 7
 digitalWrite(motorPin4, LOW);
 digitalWrite(motorPin3, LOW);
 digitalWrite(motorPin2, LOW);
 digitalWrite(motorPin1, HIGH);
 delay(motorSpeed);
 // 8
 digitalWrite(motorPin4, HIGH);
 digitalWrite(motorPin3, LOW);
 digitalWrite(motorPin2, LOW);
 digitalWrite(motorPin1, HIGH);
 delay(motorSpeed);
}


sbright33

I've asked here in the motor forum.  I have the same hardware.  How do I make it go in reverse?  I tried using step(-64) in the library, it only goes forward.  Does this work for you?  If not, should I use your code instead?  If so, who not for me?
If you fall... I'll be there for you!
-Floor

Skype Brighteyes3333
(262) 696-9619

celem

If you use my code (above) counterclockwise() for one direction, clockwise() for the other. It works!

sbright33

Thanks!  Will try it.  Why doesn't the library work?
8 codes required for 28BYJ?
Only 4 in Stepper library?
Can anyone verify this?
If you fall... I'll be there for you!
-Floor

Skype Brighteyes3333
(262) 696-9619

celem

#4
Jan 11, 2012, 01:24 pm Last Edit: Jan 11, 2012, 01:34 pm by celem Reason: 1
Eight steps because the motor requires eight steps. See the manufacturer's spec sheet at http://tinyurl.com/6tt337n. I attempted to attach it but the forum complains that the upload area is full. However, the stepper library can be made to work. See: http://arduino-info.wikispaces.com/SmallSteppers

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