Stepper library for 28BYJ-48

stepper2.ino

// This Arduino example demonstrates bidirectional operation of a 
// 28BYJ-48, which is readily available on eBay for $4.25 inc shipping,
// 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 64. 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.  
// Vin w USB power is 4.5v too slow for testing use 5v pin.
//#include <Narcoleptic.h>

#define dw digitalWrite
#define dm delayMicroseconds

const int mp1 = 4;	// Blue   - 28BYJ48 pin 1
const int mp2 = 5;	// Pink   - 28BYJ48 pin 2
const int mp3 = 6;	// Yellow - 28BYJ48 pin 3
const int mp4 = 7;	// Orange - 28BYJ48 pin 4
                        // Red    - 28BYJ48 pin 5 VCC
int motorSpeed=3000;    // set stepper speed, period actually
int stepnum=0;          // current microstep 0-7
float err=0;            // running total of movedeg - requested move, always negative in degrpm()
int ar[8];              // assigned in ccw() only, to detect abnormal torque load
int movecnt=0;          // running total of steps taken in move(), &=4095 in moveto
long m;                 // millis()
int step2,d;            // nowait
int ii,k;

void setup() {
  pinMode(mp1, OUTPUT);
  pinMode(mp2, OUTPUT);
  pinMode(mp3, OUTPUT);
  pinMode(mp4, OUTPUT);
  pinMode(13, OUTPUT);  //onboard LED
  //Serial.begin(115200);
  //degrpmslowCool4_nowait(0,180*100,1000); //10RPH
  //degrpm_nowait(1,180*100,1500);
}
void loop(){
//calloften(); delay(500);
//off();while(1); //halt
}
void unramp(boolean bcw, long deg100, int rpm100, int percslow){
//to prevent bouncing at end of move with DSLR camera mounted on shaft directly
degrpm8(bcw,deg100*(100-percslow*2)/100,rpm100); //limited to 17.00 800 12v?
degrpm8(bcw,deg100*percslow/100,400);
degrpm8(bcw,deg100*percslow/100,100);
}
void unramp1(boolean bcw, long deg100, int rpm100, int percslow){
//to prevent bouncing at end of move with DSLR camera mounted on shaft directly
//faster 20rpm for 8v, 30rpm for 12v
degrpm1(bcw,deg100*percslow/100,1500); //change for 12v
degrpm1(bcw,deg100*(100-percslow*3)/100,rpm100);
degrpm1(bcw,deg100*percslow/100,400);
degrpm1(bcw,deg100*percslow/100,100);
//off for 12v
}
const float STEPERDEG=float(64)*64/360;
//call like this moveto(90.0*STEPERDEG);
//code decides which direction to move is shortest
void moveto(int steppos){
steppos&=4095;
movecnt&=4095; //this will not happen in move() can be >4096
int bcw=0;
if(steppos>movecnt)bcw=1;
if(abs(steppos-movecnt)>2048)bcw=!bcw;
movetodir(bcw,steppos);
}
void movetodir(boolean bcw, int steppos){
//absolute position you decide direction
steppos&=4095;
movecnt&=4095; //this will not happen in move() can be >4096 or <0
while(movecnt!=steppos) {
  move(bcw);
  movecnt&=4095;
  }
//can turn off()
}
void midspeedcool_12v(boolean bcw, long steps){
//use const STEPERDEG
//no reason to use this with 5-8v
//perfect for running motor all day long
//delay 1200us already in move, dm(1200) is 50% duty cycle
//dm(400) is strong, 1200 is like 5v torque?
//<5000 smoother ok with 12v only but Cool4 is better
//change 1200 to fit your desired speed
for(long i=0;i<steps;i++){move(bcw); off(); dm(1200);} 
}
void ramp(boolean bcw, int rpm100) {
//past 1200 it ramps fast in cwss() also, thats bad, so dont do it
for(int i=50;i<1200;i+=100) //1200 or rpm100 if <1200, can change step 100
degrpmEZ(bcw,900,i); //<9.00deg ignores speed
revRestart(bcw,2,rpm100,1); //can change these
}  
void revRestart(boolean bcw, long revo, int rpm100, int xinrev) {
int j=0;
//xinrev small only
//restarts ramp in case it gets stuck due to torque load spike
if(xinrev) //>0 restarts, 0 no restart
for(long i=0;i<revo*xinrev;i++){
if(i%xinrev==0){
  //Serial.print(j++);
  //Serial.write(32);  
  }
//EZ does not delay(10) at end
degrpmEZ(bcw,36000/xinrev,rpm100); //no max
} //for
else
degrpmEZ(bcw,36000*revo,rpm100); //64 max or use rev()
}
void rev(boolean bcw, long revo) {  
long step2=revo*64*8-12; //not exactly right?
int rpm100=500; //can change
if(bcw) cwss(12,rpm100); //ramp up speed
else   ccwss(12,rpm100);
for(long i=0;i<step2;i++)
  if(bcw)cw(); else ccw();
off();
}
void degrpmslowCool4(boolean bcw, long deg100, int rph100) {  
//ccw only, more torque, less current, less heat, most efficient code for maH
//but 4x as jerky
motorSpeed=1500; //1000 or 1500 needed to pull camera 5v
int step2=deg100*64*8/360/100/2; //rounded down
int d=long(351500)*2/rph100; //see stepper.xls was /2 now *2
for(int i=0;i<step2;i++) {
ccw(); ccw(); off(); 
//can comment out line below sleeps 10ma Aroboto from 5v regulator 40ma Uno
//Narcoleptic.
delay(d);
//can hardcode cw() instead
//if(i%16==0)Serial.println(float(i+1)*360/64/8*2);
} //for
off(); //redundant
}
void degrpm_nowait(boolean bcw, long deg100, int rpm100) {  
//bcw not used pass to calloften_micro() instead
motorSpeed=1; //0?
step2=deg100*64*64/360/100;
d=long(1463600)/rpm100-20; 
m=micros();
ii=0;
}
int calloften_micro(boolean bcw){
//at least every d micros
if(ii>=step2)return(0); //saves time when done
//if(m+d-micros()<200)  //can change this
//while(micros()< m+d){}; //wait until time can change //disable this line
long ms=micros();
//if(ms>=m+d*3)Serial.println("Double-step"); //2 is double, 3 is triple
if((ms>=m+d)&&(ii<step2)){ //while would be too soon, ii< redundant
if(bcw)stepnum++; else stepnum--;
//if(bcw)movecnt++; else movecnt--;
st07();
//off(); 
m+=d; ii++;
} //if
//steps left until destination
return(step2-ii);
}
void degrpmslowCool4_nowait(boolean bcw, long deg100, int rph100) {  
//ccw only for now
motorSpeed=1500; //1000 or 1500 needed to pull camera 5v
//int or global below
step2=deg100*64*8/360/100/2;
d=long(351500)*2/rph100;
m=millis();
ii=0;
//can use global d to determine process time in loop()
//Serial.println(step2);Serial.println(d);
}
int calloften(){
//at least every d ms 
//will catch up if behind
if(ii>=step2)return(0); //saves time when done
long ms=millis();
//if(ms>=m+d*3)Serial.println("Double-step"); //2 is double, 3 is triple
while((ms>=m+d)&&(ii<step2)){
ccw(); ccw(); off(); m+=d; ii++;
//if(ii%16==1)Serial.println(float(ii)*360/64/8*2);
} //while
//steps left until destination
return(step2-ii);
}
void degrpmslowCool(boolean bcw, long deg100, int rph100) {  
//ccw only, more torque, less current, less heat
motorSpeed=1500; //why 1500 needed?
int step2=deg100*64*8/360/100; //rounded down
int d=long(351500)/2/rph100; //div 2? see stepper.xls
for(int i=0;i<step2;i++) {
//can comment out line below sleeps 10ma from 5v regulator
//Narcoleptic.delay
ccw4st1(); off(); delay(d); //cools while off
ccw4st2(); off(); delay(d);
//if(i%16==0)Serial.println(float(i+1)*360/64/8);
} //for
off(); //redundant
}
void degrpmslowHot(boolean bcw, long deg100, int rph100) {  
//ccw only, more torque, hot w 12v, use for 5v
motorSpeed=1000; //difference#1
int step2=deg100*64*8/360/100; //rounded down
int d=long(351500)/2/rph100; //div 2? see stepper.xls
for(int i=0;i<step2;i++) {
ccw4st1(); delay(d);  //difference#2 off()
ccw4st2(); delay(d);
//if(i%16==0)Serial.println(float(i+1)*360/64/8);
} //for
off();
}
void degrpmslow2(boolean bcw, long deg100, int rph100) {  
//ccw only, more torque, less current, less heat, 50% duty cycle
//compromise Hot,Cool
motorSpeed=1000; //12v
int step2=deg100*64*8/360/100; //rounded down
int d=long(351500)/2/rph100; //div 2? see stepper.xls
for(int i=0;i<step2;i++) { //only difference is below
ccw4st1(); off(); delay(d/4); st1(); delay(d/2); off(); delay(d/4);
ccw4st2(); off(); delay(d/4); st2(); delay(d/2); off(); delay(d/4);
} //for
off();
}
void degrpm1(boolean bcw, long deg100, int rpm100) {
//do your own ramping past 17RPM
long step2=deg100*64*8/360/100; //rounded down no limit
if(rpm100<50)rpm100=50; //minimum should use degrpmslow()
motorSpeed=long(1463600)/rpm100-20;  //see stepper.xls
for(long i=0;i<step2;i++)
  if(bcw)cw(); else ccw();
//can move() here to get better resolution
}
void degrpmEZ(boolean bcw, long deg100, int rpm100) {
//no delay(10) at end
//first 5 lines of degrpm  
//max 64 turns
//max 3500 rpm
int step2=deg100*64*8/360/100; //rounded down
if(rpm100<50)rpm100=50; //minimum should use degrpmslow()
rpm100=long(1463600)/rpm100-20;  //see stepper.xls
if(bcw) cwss(step2,rpm100);
else   ccwss(step2,rpm100);
}
void degrpm(boolean bcw, long deg100, int rpm100) {  
//max 64 turns or 23,000 deg or 2,300,000 deg100 long is bigger
//max 3500 rpm100 with 12v
int step2=deg100*64*8/360/100; //rounded down
if(rpm100<50)rpm100=50; //minimum should use degrpmslow()
rpm100=long(1463600)/rpm100-20;  //see stepper.xls
if(bcw) cwss(step2,rpm100);
else   ccwss(step2,rpm100);

//with this code you can step by 2.00 deg 180x will be 360+-1
//0.50 deg 720x works to 360
//even though step size is >0.50 or 0.72?
float movedeg=float(step2)*360/64/8;  //float library adds 2K size to sketch
//Serial.println(movedeg);
//Serial.println(movedeg-(float)deg100/100);  //moved too little only? never too much
err+=(movedeg-(float)deg100/100);
if(err<-1) {
motorSpeed=1200;
if(bcw) cw(); else ccw();
err+=(float(360)/64/8);
//Serial.print("err=");Serial.println(err);
} //if err
//soft stop moves further than it should
//if(bcw) cwss(15,2000);
//else   ccwss(15,2000);
delay(10); //so it stops and holds before off in loop
//off();
}
void degrpm8(boolean bcw, long deg100, int rpm100) {  
//max 8 turns
//max <<3500 rpm100 with 12v cuz no ramping ~17RPM
const int min2start=800; //800 12v, 1200 5v
long deg100a=deg100; //deg100 used later dont change
if(deg100a<300)deg100a +=4; //now err can be positive, check %=0 instead?
int step2=deg100a*64*64/360/100; //rounds up/down by 1/2 cuz +4 above, error 1/22nd of degree
if(rpm100<50)rpm100=50; //minimum should use degrpmslow()
rpm100=long(1463600)/rpm100-20;  //see stepper.xls same
motorSpeed=rpm100;
if(motorSpeed<min2start)motorSpeed=min2start;
for(int i=0;i<step2;i++) {
  if(bcw)stepnum++; else stepnum--;
  st07();
  }
//was if(bcw)cwss(step2,rpm100);
//does not adjust position for err like degrpm cuz step 0.044 or 1/22 deg small
float movedeg=float(step2)*360/64/64;  //float library adds 2K size to sketch
//Serial.println(movedeg);
err+=(movedeg-(float)deg100/100);  //not used
//Serial.println(err);
//if(err<-1) {motorSpeed=1200; if(bcw) cw(); else ccw(); err+=(float(360)/64/8);}
//off();
}
void move(boolean bcw){
motorSpeed=1200;
if(bcw)stepnum++; else stepnum--;
if(bcw)movecnt++; else movecnt--;
st07();
//if(movecnt%16==1)Serial.println(float(movecnt)*360/64/64);
}
void ccwss(int steps, int speed) {
int norm=0,last=0,nalarm=0,nar=0;
long sum=0;
//900 self starting 5v motor 5v ps
//800 most of 100% torque
//700 less torque
//600 almost none
//5v motor 12v supply:
//700 self starting
//400 decent torque
//6.6v 20RPM
//8.3v load 8.5v float 6x NiMh
//20RPM strong 
//28RPM weak
//15RPM 100% torque
//^does not overheat
//5V 10RPM strong
//5V 20RPM weak
//5V 24RPM no torque
//12V 20RPM self start 35 max speed
//if(speed<700) steps-=10;
//ramp up speed
//const int readadj=100;
motorSpeed=1000; //<12 steps, 800 for 12v
if(steps>=12) {
motorSpeed=3000; if(speed<1200) {ccw(); ccw(); steps-=2;}
motorSpeed=1200; if(speed<1200) {ccw(); ccw(); steps-=2;}
motorSpeed=800;  if(speed<800 ) {ccw(); ccw(); steps-=2;}
motorSpeed=700;  if(speed<700 ) for(int i=0;i<4;i++) {ccw(); steps--;} 
motorSpeed=speed; 
} //if
//torque load detect code to prevent destroying motor
for(int i=0;i<steps;i++){
  if(nar>=1024){ //lower for slow?
    k=sum*5/nar; //why not 6? div 0? fixed
    if((k==last)&&(!norm)&&(millis()>5*1000)) norm=k; //since program start
    if((k==last)&&(k==norm+1)) norm=k; //within 40 sec when if k>norm+0 below
    //if((k==last)&&(k==norm-1)) norm=k;
    digitalWrite(13,LOW);
    if(!norm)digitalWrite(13,HIGH); //ON until normal is found
//10,-10 for 8v level ground
// 0,-10 for 12v >30RPM only
    if(((k>norm+20)&&norm)||((k<norm-20)&&norm)){ //0,-10 can change 2B less sensitive with high load
      digitalWrite(13,HIGH);
      //will never print past 1 min
      //Serial.println();Serial.print(millis()/1000/60);Serial.print(" Min ");Serial.print(nalarm+1);Serial.println(" count");
      if(millis()>long(40)*1000){ off(); while(1);} //infinite loop
      if(nalarm++>10){ off(); while(1);} //can change 10
    } //if load
    last=k;
    sum=nar=0;
  } //if 1024 
  ccw();
  //if(i%16==0)Serial.println(float(i+1)*360/64/8);
  //can detect individual outliers here
  nar+=8; for(int j=0;j<8;j++) sum+=ar[j];
} //for
} //ccwss()

void cwss(int steps, int speed) {
motorSpeed=1000; //<12 steps, 800 for 12v
if(steps>=12) {
motorSpeed=3000; if(speed<1200) {cw(); cw(); steps-=2;}
motorSpeed=1200; if(speed<1200) {cw(); cw(); steps-=2;}
motorSpeed=800;  if(speed<800 ) {cw(); cw(); steps-=2;}
motorSpeed=700;  if(speed<700 ) for(int i=0;i<4;i++) {cw(); steps--;}
motorSpeed=speed; 
} //if
for(int i=0;i<steps;i++) cw();  //64*8 is 1 rev
//load detect code is ccwss only for now
}
void ccw4st1(){
  dw(mp1, HIGH);
  dw(mp2, LOW);
  dw(mp3, LOW);
  dw(mp4, LOW);
  dm(motorSpeed);
  //dw(mp1, HIGH);
  dw(mp2, HIGH);
  //dw(mp3, LOW);
  //dw(mp4, LOW);
  dm(motorSpeed);
  dw(mp1, LOW);
  //dw(mp2, HIGH);
  //dw(mp3, LOW);
  //dw(mp4, LOW);
  dm(motorSpeed);
  //dw(mp1, LOW);
  //dw(mp2, HIGH);
  dw(mp3, HIGH);
  //dw(mp4, LOW);
  dm(motorSpeed);
}
void st1(){
  dw(mp1, LOW);
  dw(mp2, HIGH);
  dw(mp3, HIGH);
  dw(mp4, LOW);
}
void ccw4st2(){
  dw(mp1, LOW);
  dw(mp2, LOW);
  dw(mp3, HIGH);
  dw(mp4, LOW);
  dm(motorSpeed);
  //dw(mp1, LOW);
  //dw(mp2, LOW);
  //dw(mp3, HIGH);
  dw(mp4, HIGH);
  dm(motorSpeed);
  //dw(mp1, LOW);
  //dw(mp2, LOW);
  dw(mp3, LOW);
  //dw(mp4, HIGH);
  dm(motorSpeed);
  dw(mp1, HIGH);
  //dw(mp2, LOW);
  //dw(mp3, LOW);
  //dw(mp4, HIGH);
  dm(motorSpeed);
}
void st2(){
  dw(mp1, HIGH);
  dw(mp2, LOW);
  dw(mp3, LOW);
  dw(mp4, HIGH);
}
void off(){
  dw(mp1, LOW);
  dw(mp2, LOW);
  dw(mp3, LOW);
  dw(mp4, LOW);
}
//////////////////////////////////////////////////////////////////////////////
//set pins to ULN2003 high in sequence from 1 to 4
void ccw (){
//may throw off rev() and slow() by 14us
//for j loop in ccwss() takes <2ms/rev
int ms=motorSpeed-114; //114 cuz ar 100 calibrated inc code in ccwss()>cwss()
  // 1
  dw(mp1, HIGH);
  dw(mp2, LOW);
  dw(mp3, LOW);
  dw(mp4, LOW);
ar[0]=analogRead(0);
  dm(ms);
  // 2
  dw(mp1, HIGH);
  dw(mp2, HIGH);
  dw(mp3, LOW);
  dw(mp4, LOW);
ar[1]=analogRead(0);
  dm(ms);
  // 3
  dw(mp1, LOW);
  dw(mp2, HIGH);
  dw(mp3, LOW);
  dw(mp4, LOW);
ar[2]=analogRead(0);
  dm(ms);
  // 4
  dw(mp1, LOW);
  dw(mp2, HIGH);
  dw(mp3, HIGH);
  dw(mp4, LOW);
ar[3]=analogRead(0);
  dm(ms);
  // 5
  dw(mp1, LOW);
  dw(mp2, LOW);
  dw(mp3, HIGH);
  dw(mp4, LOW);
ar[4]=analogRead(0);
  dm(ms);
  // 6
  dw(mp1, LOW);
  dw(mp2, LOW);
  dw(mp3, HIGH);
  dw(mp4, HIGH);
ar[5]=analogRead(0);
  dm(ms);
  // 7
  dw(mp1, LOW);
  dw(mp2, LOW);
  dw(mp3, LOW);
  dw(mp4, HIGH);
ar[6]=analogRead(0);
  dm(ms);
  // 8
  dw(mp1, HIGH);
  dw(mp2, LOW);
  dw(mp3, LOW);
  dw(mp4, HIGH);
ar[7]=analogRead(0);
  dm(ms);
}
//////////////////////////////////////////////////////////////////////////////
//set pins to ULN2003 high in sequence from 4 to 1
void cw(){
  // 1
  dw(mp4, HIGH);
  dw(mp3, LOW);
  dw(mp2, LOW);
  dw(mp1, LOW);
  dm(motorSpeed);
  // 2
  //dw(mp4, HIGH);
  dw(mp3, HIGH);
  //dw(mp2, LOW);
  //dw(mp1, LOW);
  dm(motorSpeed);
  // 3
  dw(mp4, LOW);
  //dw(mp3, HIGH);
  //dw(mp2, LOW);
  //dw(mp1, LOW);
  dm(motorSpeed);
  // 4
  //dw(mp4, LOW);
  //dw(mp3, HIGH);
  dw(mp2, HIGH);
  //dw(mp1, LOW);
  dm(motorSpeed);
  // 5
  //dw(mp4, LOW);
  dw(mp3, LOW);
  //dw(mp2, HIGH);
  //dw(mp1, LOW);
  dm(motorSpeed);
  // 6
  //dw(mp4, LOW);
  //dw(mp3, LOW);
  //dw(mp2, HIGH);
  dw(mp1, HIGH);
  dm(motorSpeed);
  // 7
  //dw(mp4, LOW);
  //dw(mp3, LOW);
  dw(mp2, LOW);
  //dw(mp1, HIGH);
  dm(motorSpeed);
  // 8
  dw(mp4, HIGH);
  //dw(mp3, LOW);
  //dw(mp2, LOW);
  //dw(mp1, HIGH);
  dm(motorSpeed);
}
void st07(){
if(stepnum==-1)stepnum=7;
if(stepnum== 8)stepnum=0;
switch(stepnum){
case 0:
  dw(mp4, HIGH);
  dw(mp3, LOW);
  dw(mp2, LOW);
  dw(mp1, LOW);
  break;
case 1:
  dw(mp4, HIGH);
  dw(mp3, HIGH);
  dw(mp2, LOW);
  dw(mp1, LOW);
  break;
case 2:
  dw(mp4, LOW);
  dw(mp3, HIGH);
  dw(mp2, LOW);
  dw(mp1, LOW);
  break;
case 3:
  dw(mp4, LOW);
  dw(mp3, HIGH);
  dw(mp2, HIGH);
  dw(mp1, LOW);
  break;
case 4:
  dw(mp4, LOW);
  dw(mp3, LOW);
  dw(mp2, HIGH);
  dw(mp1, LOW);
  break;
case 5:
  dw(mp4, LOW);
  dw(mp3, LOW);
  dw(mp2, HIGH);
  dw(mp1, HIGH);
  break;
case 6:
  dw(mp4, LOW);
  dw(mp3, LOW);
  dw(mp2, LOW);
  dw(mp1, HIGH);
  break;
case 7:
  dw(mp4, HIGH);
  dw(mp3, LOW);
  dw(mp2, LOW);
  dw(mp1, HIGH);
  break;
}
//for all cases
dm(motorSpeed);
}

stepper2.txt

Includes ability to step less than step size without losing track of total.  
Detect torque spike when you get to end of travel.  
Turns off coils between steps for motor with gears that do not need holding torque.  
Cooler running with 12v.  
Can sleep when moving slow.  
Ramping.  
Non-blocking.  
Enhanced performance using 12v supply with 5v motor.

Here's a summary and some help to get you started:
http://arduino.cc/forum/index.php/topic,89159.0

From above link:
Here is a brief summary of the code.
It can spin a full size DSLR on it's shaft without bearings at 30RPM! 
Ramping up and slowing down to prevent bouncing.
It can measure torque to detect an abnormal load or error.
It works without blocking or waiting or interrupts.
Enhanced performance using 12v without warming up the motor.
And much more!
Sounds like an advert, but it's all for Free.
Hardware is $4.

Please leave comments here! Bugs? Enhancements? Questions? Feature request?

Where do comments go?

how can I use your code with ramps 1.4? it seems to be well written!