The Big Easy Stepper Motor Driver + Arduino

[ameyer]

From: http://bildr.org/2012/11/big-easy-driver-arduino/


[[Step Motor|Stepper]] (or step) motors are really cool. They are perfect for automation or any time you need a motor to turn to a specific point, at a specific speed, in a specific direction. And, unlike typical motors, steppers are able to do all of this, and hold their position when they are not moving - The trade off is that they cant move as fast, and you have to power them at full power all the time, but you get total control in ...

[okay1984]

Really nice and useful tutorial. Thanks a lot.

[OceanStudio]

I used this article to help me get a combination of an Arduino Uno and the smaller "Easy Driver" board working with a "Mercury" stepper motor that I got from SparkFun.

First off, thanks for the very clear instructions and diagrams. This is my first Arduino project and I was up and running within the first few hours of following your instructions. Of course, now experimentation sparks some questions...

I'll keep it to one question for now as I don't want to load up this thread if other questions are better suited elsewhere in your forums.

In a quest to make the smallest form factor of a single stepper motor drive circuit, do you think it is possible to use an Arduino Mico or Nano board instead of the Uno in order to make the entire drive assembly as small as possible?

[ameyer]

Yeah, there is nothing special about the uno in this case. You can use any arduino the same way.

I used this article to help me get a combination of an Arduino Uno and the smaller "Easy Driver" board working with a "Mercury" stepper motor that I got from SparkFun.

First off, thanks for the very clear instructions and diagrams. This is my first Arduino project and I was up and running within the first few hours of following your instructions. Of course, now experimentation sparks some questions...

I'll keep it to one question for now as I don't want to load up this thread if other questions are better suited elsewhere in your forums.

In a quest to make the smallest form factor of a single stepper motor drive circuit, do you think it is possible to use an Arduino Mico or Nano board instead of the Uno in order to make the entire drive assembly as small as possible?

[OceanStudio]

Hello AMeyer,

I used your previous "Easy Driver" blog post to get an Arduino+Easy Driver set-up working with simple functions but immediately saw the shortcomings of the "blocking" code it functions on...after your advice to utilize a "Big Easy Driver" I currently have a nice little set-up using an Arduino Micro + Big Easy Driver combo. After uploading the sample code you provided for a single stepper motor (I'm using 12V Mercury model currently) I can already see how improved the Arduino Stepper Library is going to be as compared to the previous Easy Driver code.

First off, I'd like to share with anyone that may be wondering...The "Big" Easy Driver is actually not very 'big' at all. I'm trying to make an extremely compact sized project box for my driver and the name of the "Big Easy Driver" compared to the title of "Easy Driver" is the original reason I went with the Easy Driver for round one...The Big Easy Driver is actually thinner in width and just a tad taller in height when comparing the two together. This was a pleasant surprise for me as I can still have an extremely small project box when combining the Arduino Micro board with the Big Easy Driver board...

For this post, I just have one question:
Is it ok to run 12V to the Aduino Micro board on a continuous basis? I'm not sure if it has a decent voltage regulator as part of it's design...

In my breadboard set-up, I'm powering the Arduino Micro with the same 12V that is being supplied to the Big Easy Driver board which of course ultimately supplies the Mercury motor (rated at 12V). When I run the sample code, the Big Easy board does not get hot, the Micro board stays cool as well, but the motor will warm up even when I turn the current down (then motor runs choppy though..)
My goal is to switch to a 28V motor at some point (to increase torque and hopefully extend battery life) and tap/alter the battery pack to supply 12V (or lower) to the Arduino Micro and 28V to the Big Easy Driver. I'd really like to use a single battery pack that can power both the arduino and driver boards with their separate voltages...

[OceanStudio]

My next question concerning an Arduino Micro + Big Easy Driver combination is how to add a potentiometer to the mix for direction/speed control...

I looked at the documentation here - http://arduino.cc/en/Tutorial/MotorKnob
and there are some things that are unclear to me as a complete novice in this new world of electronics and programing.

That Arduino article shows diagrams for Stepper motors that are being controlled by either a Darlington Array (unipolar) or an H-Bridge chip (bipolar). I understand that the Big Easy Driver is a replacement for all of the circuitry shown in the 'MotorKnob' documentation, but some of the description of the application of the potentiometer has me scratching my head.
The documentation states that

Note: Both circuits below are four wire configurations. Two wire configurations will not work with the code provided.

I'm assuming that the quote is referring to the fact that four wire stepper motors are needed for the code and it's not referring to the amount of outputs used from the Arduino board, which happen to be four wires as well.

The example code provided there has this statement:

Code: Select all

// create an instance of the stepper class, specifying
// the number of steps of the motor and the pins it's
// attached to
Stepper stepper(STEPS, 8, 9, 10, 11);

and your 'Bildr.org' sample code has this type of statement:

Code: Select all

int motorDirPin = 2; //digital pin 2
int motorStepPin = 3; //digital pin 3

//set up the accelStepper intance
//the "1" tells it we are using a driver
AccelStepper stepper(1, motorStepPin, motorDirPin);

As I begin to use the Stepper Library from the Arduino site, do I simply interject your lines of code to set up the Arduino board on pins 2 and 3 in order to use the Stepper Library code to control the Big Easy Driver...?

Then after that, their instructions for wiring a poetentiometer only states:

In both circuits, connect a 10k pot to power and ground, with it's wiper outputting to analog pin 0.

To me, as an amateur in electronics, does that mean to wire 12V or a lower voltage to one side of the pot, and then ground out the other side of the pot...and then wire the center 'wiper' lead from the pot to the Analog '0' pin on the Arduino...?
Very sorry to be so basic in questions, I've never wired a potentiometer and don't even really know which lead is the 'wiper' coming from the pot...

[ameyer]

You are way over thinking things.
First off read the "Motor Voltage / Current" section of http://bildr.org/2012/11/big-easy-driver-arduino/ you do not power the motor, you power the driver. The driver will power the motor.

Steppers are usually rated to 90ºc (near boiling temp), so dont worry about the heat.

Steppers use the most energy standing still, so battery powered is going to drain very very fast.

12V to the arduino is fine. That is the top of the recommended input, not the absolute maximum.

Dont even look at that arduino example code, it has nothing to do with you if you are using a stepper driver.

When connecting a pot, you connect from the 5V pin, not the raw/battery power. (like this http://arduino.cc/en/uploads/Tutorial/potentiometer.jpg )


Try this code.
For this example, think of steps as a measurement of distance or position.
So a separate control for direction is not needed because you tell it where to go and it will go there.

If you are at step 0 and you say to go to 500, that is one direction. But if you are at step 1000, and you say to go to step 500, that is the opposite direction.

This code just uses one pot (on analog 0) to control the position of the motor. When you turn it to 0, the motor will go to the starting point. When you turn it all the way it will move to step 1024 * ( multiplier ).

I set multiplier to 10. So if you do not change it, it will move upto 10240 steps out. And if you turn the pot half way, the motor will go to step 5120.

Code: Select all

int multiplier = 10; //change this depending if you need the stepper to move more or less




#include <AccelStepper.h>

int motorSpeed = 9600; //maximum steps per second (about 3rps / at 16 microsteps)
int motorAccel = 80000; //steps/second/second to accelerate

int motorDirPin = 2; //digital pin 2
int motorStepPin = 3; //digital pin 3

//set up the accelStepper intance
//the "1" tells it we are using a driver
AccelStepper stepper(1, motorStepPin, motorDirPin);



void setup(){
  stepper.setMaxSpeed(motorSpeed);
  stepper.setSpeed(motorSpeed);
  stepper.setAcceleration(motorAccel);
 
}

void loop(){
 
  int positionToGoTo = analogRead(A0);
  stepper.moveTo(positionToGoTo * multiplier);
 
 
  //these must be called as often as possible to ensure smooth operation
  //any delay will cause jerky motion
  stepper.run();
}



My next question concerning an Arduino Micro + Big Easy Driver combination is how to add a potentiometer to the mix for direction/speed control...

I looked at the documentation here - http://arduino.cc/en/Tutorial/MotorKnob
and there are some things that are unclear to me as a complete novice in this new world of electronics and programing.

That Arduino article shows diagrams for Stepper motors that are being controlled by either a Darlington Array (unipolar) or an H-Bridge chip (bipolar). I understand that the Big Easy Driver is a replacement for all of the circuitry shown in the 'MotorKnob' documentation, but some of the description of the application of the potentiometer has me scratching my head.
The documentation states that

Note: Both circuits below are four wire configurations. Two wire configurations will not work with the code provided.

I'm assuming that the quote is referring to the fact that four wire stepper motors are needed for the code and it's not referring to the amount of outputs used from the Arduino board, which happen to be four wires as well.

The example code provided there has this statement:

Code: Select all

// create an instance of the stepper class, specifying
// the number of steps of the motor and the pins it's
// attached to
Stepper stepper(STEPS, 8, 9, 10, 11);

and your 'Bildr.org' sample code has this type of statement:

Code: Select all

int motorDirPin = 2; //digital pin 2
int motorStepPin = 3; //digital pin 3

//set up the accelStepper intance
//the "1" tells it we are using a driver
AccelStepper stepper(1, motorStepPin, motorDirPin);

As I begin to use the Stepper Library from the Arduino site, do I simply interject your lines of code to set up the Arduino board on pins 2 and 3 in order to use the Stepper Library code to control the Big Easy Driver...?

Then after that, their instructions for wiring a poetentiometer only states:

In both circuits, connect a 10k pot to power and ground, with it's wiper outputting to analog pin 0.

To me, as an amateur in electronics, does that mean to wire 12V or a lower voltage to one side of the pot, and then ground out the other side of the pot...and then wire the center 'wiper' lead from the pot to the Analog '0' pin on the Arduino...?
Very sorry to be so basic in questions, I've never wired a potentiometer and don't even really know which lead is the 'wiper' coming from the pot...

[OceanStudio]

Sorry again for those lengthy newbie posts but I'm so new to this I just needed those clarifications...
Your answers are very clear and helpful, thank you so much!

I have always understood all instructions from your blog posts here at Bildr for the Easy Driver and now the Big Easy Driver...it was just the comparison to the documentation at Arduino that was confusing me as I have no background in anything Arduino or electronics.

Now it is very clear to me that when using a Big Easy Driver I can not just simply copy and paste from the Arduino Stepper Libraries and change the setup code to talk to pins 2,3 instead of 8,9,10,11...
Thank you very much for the sample code, that is a huge help for newbies like myself.

Also a huge thanks for posting the wiring image of the Potentiometer...The arduino documentation just said "connect to power and ground" and left me wondering if I should connect the power to the 12V source power or other...I'm so new to this that I just needed to see your image of the potentiometer connected to the 5V power out of the Arduino board, and now it all makes perfect sense!

I have now successfully connected a potentiometer and used your code to drive the motor forwards and backwards by control of the potentiometer. I will begin to play with the code to adjust speeds, and "smoothing" starts and stops with the 'motorAccel' portion of the code.

Thanks so much for your patience, clear explanations and especially the sample code!

[ameyer]

Im glad it helped!
Also glad to know the writing is easy to follow. I do my best to write for people who dont do a lot with electronics, but want to make something.

Sorry again for those lengthy newbie posts but I'm so new to this I just needed those clarifications...
Your answers are very clear and helpful, thank you so much!

I have always understood all instructions from your blog posts here at Bildr for the Easy Driver and now the Big Easy Driver...it was just the comparison to the documentation at Arduino that was confusing me as I have no background in anything Arduino or electronics.

Now it is very clear to me that when using a Big Easy Driver I can not just simply copy and paste from the Arduino Stepper Libraries and change the setup code to talk to pins 2,3 instead of 8,9,10,11...
Thank you very much for the sample code, that is a huge help for newbies like myself.

Also a huge thanks for posting the wiring image of the Potentiometer...The arduino documentation just said "connect to power and ground" and left me wondering if I should connect the power to the 12V source power or other...I'm so new to this that I just needed to see your image of the potentiometer connected to the 5V power out of the Arduino board, and now it all makes perfect sense!

I have now successfully connected a potentiometer and used your code to drive the motor forwards and backwards by control of the potentiometer. I will begin to play with the code to adjust speeds, and "smoothing" starts and stops with the 'motorAccel' portion of the code.

Thanks so much for your patience, clear explanations and especially the sample code!

[hallmat]

Hello Ameyer,

i followed your guide except i am using a nano not a uno and for the life of me i cannot get it to drive my nema 23 i have a 24v 14A supply to the BED but nothing is working the motor just makes noises and nothing happens
*EDIT* i have tried to physically move the shaft but its solid under power *edit*

any idea on how to fix this i have Googled about but cannot find anything

Many thanks

Matthew

[ameyer]

So when it should be moving, it just sits there and makes noise?

My guess is that the motor is someway or another not hooked up correctly, or the direction and step pins are messed up.
Using a nano shouldn't change anything (I don't think)

Hello Ameyer,

i followed your guide except i am using a nano not a uno and for the life of me i cannot get it to drive my nema 23 i have a 24v 14A supply to the BED but nothing is working the motor just makes noises and nothing happens
*EDIT* i have tried to physically move the shaft but its solid under power *edit*

any idea on how to fix this i have Googled about but cannot find anything

Many thanks

Matthew

[hallmat]

[quote="ameyer"]So when it should be moving, it just sits there and makes noise?

My guess is that the motor is someway or another not hooked up correctly, or the direction and step pins are messed up.
Using a nano shouldn't change anything (I don't think)



Hey,

i had it working two minuets ago then it went jittery and now its just gone back to doing the noise and vibration

the code that got it working was this

Code: Select all


#include <AccelStepper.h>

int motorSpeed = 32000; //maximum steps per second (about 3rps / at 16 microsteps)
int motorAccel = 80000; //steps/second/second to accelerate

int motorDirPin = 3; //digital pin 2
int motorStepPin = 2; //digital pin 3

//set up the accelStepper intance
//the "1" tells it we are using a driver
AccelStepper stepper(1, motorStepPin, motorDirPin);



void setup(){
stepper.setMaxSpeed(motorSpeed);
stepper.setSpeed(motorSpeed);
stepper.setAcceleration(motorAccel);

stepper.moveTo(32000); //move 32000 steps (should be 10 rev)
}

void loop(){

//if stepper is at desired location
if (stepper.distanceToGo() == 0){
//go the other way the same amount of steps
//so if current position is 400 steps out, go position -400
stepper.moveTo(-stepper.currentPosition());
}



//these must be called as often as possible to ensure smooth operation
//any delay will cause jerky motion
stepper.run();
}



and now its not i wonder why its doing it

[ameyer]

It could be a lot of things, the acceleration or speed could be too much for the motor.
This is the simplest of all codes to see if the hardware works:

Code: Select all


//////////////////////////////////////////////////////////////////
//©2011 bildr
//Released under the MIT License - Please reuse change and share
//Using the easy stepper with your arduino
//use rotate and/or rotateDeg to controll stepper motor
//speed is any number from .01 -> 1 with 1 being fastest -
//Slower Speed == Stronger movement
/////////////////////////////////////////////////////////////////


#define DIR_PIN 2
#define STEP_PIN 3

void setup() {
  pinMode(DIR_PIN, OUTPUT);
  pinMode(STEP_PIN, OUTPUT);
}

void loop(){
  //rotate a specific number of microsteps (8 microsteps per step)
  //a 200 step stepper would take 1600 micro steps for one full revolution
  rotate(1600, .3);
  delay(1000);

  rotate(-1600, .15); //reverse
  delay(1000);
}



void rotate(int steps, float speed){
  //rotate a specific number of microsteps (8 microsteps per step) - (negitive for reverse movement)
  //speed is any number from .01 -> 1 with 1 being fastest - Slower is stronger
  int dir = (steps > 0)? HIGH:LOW;
  steps = abs(steps);

  digitalWrite(DIR_PIN,dir);

  float usDelay = (1/speed) * 70;

  for(int i=0; i < steps; i++){
    digitalWrite(STEP_PIN, HIGH);
    delayMicroseconds(usDelay);

    digitalWrite(STEP_PIN, LOW);
    delayMicroseconds(usDelay);
  }
}



So when it should be moving, it just sits there and makes noise?

My guess is that the motor is someway or another not hooked up correctly, or the direction and step pins are messed up.
Using a nano shouldn't change anything (I don't think)



Hey,

i had it working two minuets ago then it went jittery and now its just gone back to doing the noise and vibration

the code that got it working was this

Code: Select all


#include <AccelStepper.h>

int motorSpeed = 32000; //maximum steps per second (about 3rps / at 16 microsteps)
int motorAccel = 80000; //steps/second/second to accelerate

int motorDirPin = 3; //digital pin 2
int motorStepPin = 2; //digital pin 3

//set up the accelStepper intance
//the "1" tells it we are using a driver
AccelStepper stepper(1, motorStepPin, motorDirPin);



void setup(){
stepper.setMaxSpeed(motorSpeed);
stepper.setSpeed(motorSpeed);
stepper.setAcceleration(motorAccel);

stepper.moveTo(32000); //move 32000 steps (should be 10 rev)
}

void loop(){

//if stepper is at desired location
if (stepper.distanceToGo() == 0){
//go the other way the same amount of steps
//so if current position is 400 steps out, go position -400
stepper.moveTo(-stepper.currentPosition());
}



//these must be called as often as possible to ensure smooth operation
//any delay will cause jerky motion
stepper.run();
}



and now its not i wonder why its doing it

[hallmat]

[quote="ameyer"]It could be a lot of things, the acceleration or speed could be too much for the motor.
This is the simplest of all codes to see if the hardware works:

Code: Select all


//////////////////////////////////////////////////////////////////
//©2011 bildr
//Released under the MIT License - Please reuse change and share
//Using the easy stepper with your arduino
//use rotate and/or rotateDeg to controll stepper motor
//speed is any number from .01 -> 1 with 1 being fastest -
//Slower Speed == Stronger movement
/////////////////////////////////////////////////////////////////


#define DIR_PIN 2
#define STEP_PIN 3

void setup() {
  pinMode(DIR_PIN, OUTPUT);
  pinMode(STEP_PIN, OUTPUT);
}

void loop(){
  //rotate a specific number of microsteps (8 microsteps per step)
  //a 200 step stepper would take 1600 micro steps for one full revolution
  rotate(1600, .3);
  delay(1000);

  rotate(-1600, .15); //reverse
  delay(1000);
}



void rotate(int steps, float speed){
  //rotate a specific number of microsteps (8 microsteps per step) - (negitive for reverse movement)
  //speed is any number from .01 -> 1 with 1 being fastest - Slower is stronger
  int dir = (steps > 0)? HIGH:LOW;
  steps = abs(steps);

  digitalWrite(DIR_PIN,dir);

  float usDelay = (1/speed) * 70;

  for(int i=0; i < steps; i++){
    digitalWrite(STEP_PIN, HIGH);
    delayMicroseconds(usDelay);

    digitalWrite(STEP_PIN, LOW);
    delayMicroseconds(usDelay);
  }
}



that just did the same thing it does not see to change when i change anything in the sketch

[ameyer]

It is 100% a hardware issue then. Either it is not hooked up right, something is broken, or you dont have enough power coming from your power supply(have you checked it with a voltage meter to make sure it is outputting what it should?)

It could be a lot of things, the acceleration or speed could be too much for the motor.
This is the simplest of all codes to see if the hardware works:

Code: Select all


//////////////////////////////////////////////////////////////////
//©2011 bildr
//Released under the MIT License - Please reuse change and share
//Using the easy stepper with your arduino
//use rotate and/or rotateDeg to controll stepper motor
//speed is any number from .01 -> 1 with 1 being fastest -
//Slower Speed == Stronger movement
/////////////////////////////////////////////////////////////////


#define DIR_PIN 2
#define STEP_PIN 3

void setup() {
  pinMode(DIR_PIN, OUTPUT);
  pinMode(STEP_PIN, OUTPUT);
}

void loop(){
  //rotate a specific number of microsteps (8 microsteps per step)
  //a 200 step stepper would take 1600 micro steps for one full revolution
  rotate(1600, .3);
  delay(1000);

  rotate(-1600, .15); //reverse
  delay(1000);
}



void rotate(int steps, float speed){
  //rotate a specific number of microsteps (8 microsteps per step) - (negitive for reverse movement)
  //speed is any number from .01 -> 1 with 1 being fastest - Slower is stronger
  int dir = (steps > 0)? HIGH:LOW;
  steps = abs(steps);

  digitalWrite(DIR_PIN,dir);

  float usDelay = (1/speed) * 70;

  for(int i=0; i < steps; i++){
    digitalWrite(STEP_PIN, HIGH);
    delayMicroseconds(usDelay);

    digitalWrite(STEP_PIN, LOW);
    delayMicroseconds(usDelay);
  }
}



that just did the same thing it does not see to change when i change anything in the sketch

[hallmat]

[quote="ameyer"]It is 100% a hardware issue then. Either it is not hooked up right, something is broken, or you dont have enough power coming from your power supply(have you checked it with a voltage meter to make sure it is outputting what it should?)


but it was working for about 10 mins and nothing was changed it just went jittery and now it wont do anything

can you reccomend an alternative to the BED??

[ameyer]

For that price and size - Pololu makes a lot: http://www.pololu.com/catalog/category/120

Do you have anything else you could use to test the motor? Just to see if it is something else.
You could also try different pins on the arduiono just to see if somehow it was that.

It is 100% a hardware issue then. Either it is not hooked up right, something is broken, or you dont have enough power coming from your power supply(have you checked it with a voltage meter to make sure it is outputting what it should?)

but it was working for about 10 mins and nothing was changed it just went jittery and now it wont do anything

can you reccomend an alternative to the BED??

[hallmat]

For that price and size - Pololu makes a lot: http://www.pololu.com/catalog/category/120

Do you have anything else you could use to test the motor? Just to see if it is something else.
You could also try different pins on the arduiono just to see if somehow it was that.

Hey,

nope i had some easy drivers before this and now i cant find them as was gonna test it with that and see what happens, tried different pins on the arduino but nothing and the motors not even holding torque so its gotta be the BED than

[ameyer]

If you checked the power supply and it is supplying enough voltage (check it when it is connected), then yeah, it is most likely the BED.

For that price and size - Pololu makes a lot: http://www.pololu.com/catalog/category/120

Do you have anything else you could use to test the motor? Just to see if it is something else.
You could also try different pins on the arduiono just to see if somehow it was that.

Hey,

nope i had some easy drivers before this and now i cant find them as was gonna test it with that and see what happens, tried different pins on the arduino but nothing and the motors not even holding torque so its gotta be the BED than

[hallmat]

If you checked the power supply and it is supplying enough voltage (check it when it is connected), then yeah, it is most likely the BED.

For that price and size - Pololu makes a lot: http://www.pololu.com/catalog/category/120

Do you have anything else you could use to test the motor? Just to see if it is something else.
You could also try different pins on the arduiono just to see if somehow it was that.

Hey,

nope i had some easy drivers before this and now i cant find them as was gonna test it with that and see what happens, tried different pins on the arduino but nothing and the motors not even holding torque so its gotta be the BED than

The current to the big easy driver from supply was 14 amps and the voltage was 24v so there was plenty of power going to it,

Is there a wiring guide that you have done for the polou drivers? To the arduino?

Thanks for your help

[ameyer]

I personally have never used the Pololu drivers, so I dont have a wiring diagram for them. But they are very similar to how the BED works. Im sure they have some documentation somewhere.

If you checked the power supply and it is supplying enough voltage (check it when it is connected), then yeah, it is most likely the BED.

For that price and size - Pololu makes a lot: http://www.pololu.com/catalog/category/120

Do you have anything else you could use to test the motor? Just to see if it is something else.
You could also try different pins on the arduiono just to see if somehow it was that.

Hey,

nope i had some easy drivers before this and now i cant find them as was gonna test it with that and see what happens, tried different pins on the arduino but nothing and the motors not even holding torque so its gotta be the BED than

The current to the big easy driver from supply was 14 amps and the voltage was 24v so there was plenty of power going to it,

Is there a wiring guide that you have done for the polou drivers? To the arduino?

Thanks for your help