Stepper motor with driver module in Arduino - Step-by-Step Execution

Concept Flow - Stepper motor with driver module

Start

↓

Setup pins

↓

Initialize stepper

↓

Loop start

↓

Send step pulse

↓

Delay for speed

↓

Update step count

↓

Check if steps done?

No→Loop start

Yes↓

Stop motor

↓

End or repeat

The program sets up pins, then repeatedly sends pulses to the driver to move the motor step by step until the desired steps are done.

Execution Sample

Arduino

const int stepPin = 3;
const int dirPin = 4;
int steps = 200;

void setup() {
  pinMode(stepPin, OUTPUT);
  pinMode(dirPin, OUTPUT);
  digitalWrite(dirPin, HIGH);
}

void loop() {
  for (int i = 0; i < steps; i++) {
    digitalWrite(stepPin, HIGH);
    delayMicroseconds(1000);
    digitalWrite(stepPin, LOW);
    delayMicroseconds(1000);
  }
  while(true) {}
}

This code moves the stepper motor 200 steps in one direction by sending pulses to the step pin with delays controlling speed.

Execution Table

Step	i (step count)	Condition i<steps	Action	Pin stepPin state	Delay (us)
1	0	True	Set stepPin HIGH	HIGH	1000
2	0	True	Set stepPin LOW	LOW	1000
3	1	True	Set stepPin HIGH	HIGH	1000
4	1	True	Set stepPin LOW	LOW	1000
5	2	True	Set stepPin HIGH	HIGH	1000
6	2	True	Set stepPin LOW	LOW	1000
...	...	...	...	...	...
399	199	True	Set stepPin HIGH	HIGH	1000
400	199	True	Set stepPin LOW	LOW	1000
401	200	False	Exit loop	LOW	0

💡 i reaches 200, condition i<200 is False, loop ends

Variable Tracker

Variable	Start	After 1	After 2	After 3	...	Final
i	-	0	1	2	...	200
stepPin state	LOW	HIGH	LOW	HIGH	...	LOW

Key Moments - 3 Insights

Why do we set stepPin HIGH and then LOW in each loop iteration?

Because the stepper driver moves the motor one step on the rising edge (HIGH) of the stepPin signal, then setting it LOW prepares for the next pulse. See execution_table rows 1-2.

What controls the speed of the motor steps?

The delayMicroseconds(1000) between setting stepPin HIGH and LOW controls how fast pulses are sent, thus controlling motor speed. See execution_table 'Delay (us)' column.

Why does the loop stop after 200 steps?

Because the for loop condition i < steps becomes false when i reaches 200, stopping pulses and motor movement. See execution_table last row.

Visual Quiz - 3 Questions

Look at the execution_table, what is the state of stepPin at step 3?

A Undefined

B LOW

C HIGH

D No change

💡 Hint

Check the 'Pin stepPin state' column at step 3 in the execution_table.

At which iteration does the loop condition become false?

A 199

B 200

C 201

D 100

💡 Hint

Look at the last row of execution_table where i reaches 200 and condition is false.

If delayMicroseconds is increased, how does the execution_table change?

A Delay values increase, motor steps slower

B Delay values decrease, motor steps faster

C No change in delay values

D Loop ends earlier

💡 Hint

Refer to the 'Delay (us)' column in execution_table and how delay controls speed.

Concept Snapshot

Stepper motor with driver module:
- Use two pins: DIR for direction, STEP for steps
- Set DIR pin HIGH or LOW to choose direction
- Send pulses on STEP pin: HIGH then LOW for each step
- Delay between pulses controls speed
- Loop for desired number of steps
- Stop after steps done

Full Transcript

This example shows how to control a stepper motor using a driver module with Arduino. First, pins for step and direction are set as outputs. Direction pin is set HIGH to choose rotation direction. Then, in the loop, a for loop runs for the number of steps needed. Each iteration sends a pulse by setting the step pin HIGH, waiting a short delay, then LOW, and waiting again. This pulse makes the motor move one step. The delay controls how fast the motor steps. When the loop finishes, the motor stops. The execution table traces each step pin change and delay. Variables like the step counter 'i' and pin states are tracked. Common confusions include why the step pin toggles HIGH then LOW, how speed is controlled by delay, and why the loop stops after the set steps. The quiz questions check understanding of pin states, loop exit, and delay effects. This visual trace helps beginners see exactly how the motor driver is controlled step by step.

Practice

1. What is the main role of a driver module when controlling a stepper motor with Arduino?

easy

A. To store the motor's position data

B. To increase the speed of the Arduino board

C. To safely provide the correct power and signals to the motor

D. To convert analog signals to digital

Solution

1. Step 1: Understand the function of a driver module

   The driver module acts as a bridge between Arduino and the stepper motor, providing the right voltage and current safely.

2. Step 2: Identify the correct role

   It controls power and signals to the motor, preventing damage and ensuring proper movement.

3. Final Answer:

   To safely provide the correct power and signals to the motor -> Option C

4. Quick Check:

   Driver module = safe power and signals [OK]

Hint: Driver modules protect motor and Arduino by controlling power [OK]

Common Mistakes:

• Thinking driver speeds up Arduino
• Believing driver stores position data
• Confusing driver with signal converter

2. Which Arduino code snippet correctly sets the direction pin to HIGH for a stepper motor driver?

easy

A. digitalWrite(directionPin, low);

B. digitalWrite(directionPin, "HIGH");

C. digitalWrite(directionPin, 0);

D. digitalWrite(directionPin, HIGH);

Solution

1. Step 1: Check correct syntax for digitalWrite

   The function digitalWrite(pin, value) expects the value to be HIGH or LOW without quotes and case-sensitive.

2. Step 2: Identify correct usage

   digitalWrite(directionPin, HIGH); uses digitalWrite(directionPin, HIGH); which is correct syntax and case.

3. Final Answer:

   digitalWrite(directionPin, HIGH); -> Option D

4. Quick Check:

   digitalWrite with HIGH (uppercase, no quotes) [OK]

Hint: Use uppercase HIGH/LOW without quotes in digitalWrite [OK]

Common Mistakes:

• Using lowercase 'low' instead of 'LOW'
• Passing numbers instead of HIGH/LOW constants
• Using quotes around HIGH or LOW

3. What will be the output behavior of this Arduino code controlling a stepper motor driver?

const int stepPin = 3;
const int dirPin = 4;

void setup() {
  pinMode(stepPin, OUTPUT);
  pinMode(dirPin, OUTPUT);
  digitalWrite(dirPin, HIGH);
}

void loop() {
  digitalWrite(stepPin, HIGH);
  delay(2);
  digitalWrite(stepPin, LOW);
  delay(2);
}

medium

A. The code will cause a compile error

B. The motor will rotate continuously in one direction at a slow speed

C. The motor will not move because direction is not set

D. The motor will rotate once and stop

Solution

1. Step 1: Analyze pin setup and direction

   Direction pin is set to HIGH once in setup, so motor direction is fixed.

2. Step 2: Analyze loop step pulses

   Loop sends pulses to stepPin with 2ms HIGH and 2ms LOW delays, causing continuous stepping.

3. Final Answer:

   The motor will rotate continuously in one direction at a slow speed -> Option B

4. Quick Check:

   Continuous pulses + fixed direction = continuous rotation [OK]

Hint: Continuous step pulses with fixed direction cause continuous rotation [OK]

Common Mistakes:

• Thinking motor moves once then stops
• Assuming direction not set means no movement
• Expecting compile errors from correct code

4. Identify the error in this Arduino code snippet for controlling a stepper motor driver:

int stepPin = 5;
int dirPin = 6;

void setup() {
  pinMode(stepPin, OUTPUT);
  pinMode(dirPin, OUTPUT);
  digitalWrite(dirPin, HIGH);
}

void loop() {
  digitalWrite(stepPin, HIGH);
  delay(1);
  digitalWrite(stepPin, HIGH);
  delay(1);
}

medium

A. The stepPin is never set to LOW, so no step pulse is generated

B. The direction pin is not set as input

C. The delay time is too short to move the motor

D. The pinMode calls are missing

Solution

1. Step 1: Check step pulse signal

   Step pulses require a HIGH then LOW transition to trigger a step.

2. Step 2: Identify missing LOW signal

   Code sets stepPin HIGH twice without setting it LOW in between, so no pulse occurs.

3. Final Answer:

   The stepPin is never set to LOW, so no step pulse is generated -> Option A

4. Quick Check:

   Step pulse = HIGH then LOW [OK]

Hint: Step pulse needs HIGH then LOW transition [OK]

Common Mistakes:

• Forgetting to set stepPin LOW after HIGH
• Confusing direction pin mode
• Assuming short delay fixes pulse issue

5. You want to rotate a stepper motor exactly 200 steps clockwise, then 200 steps counterclockwise using a driver module. Which Arduino code snippet correctly achieves this?

hard

A. for(int i=0; i<200; i++) { digitalWrite(dirPin, HIGH); digitalWrite(stepPin, HIGH); delay(1); digitalWrite(stepPin, LOW); delay(1); } for(int i=0; i<200; i++) { digitalWrite(dirPin, LOW); digitalWrite(stepPin, HIGH); delay(1); digitalWrite(stepPin, LOW); delay(1); }

B. digitalWrite(dirPin, HIGH); for(int i=0; i<=200; i++) { digitalWrite(stepPin, HIGH); delay(1); digitalWrite(stepPin, LOW); delay(1); } digitalWrite(dirPin, LOW); for(int i=0; i<=200; i++) { digitalWrite(stepPin, HIGH); delay(1); digitalWrite(stepPin, LOW); delay(1); }

C. for(int i=0; i<200; i++) { digitalWrite(stepPin, HIGH); delay(1); digitalWrite(stepPin, LOW); delay(1); } digitalWrite(dirPin, HIGH); for(int i=0; i<200; i++) { digitalWrite(stepPin, HIGH); delay(1); digitalWrite(stepPin, LOW); delay(1); }

D. digitalWrite(dirPin, HIGH); digitalWrite(stepPin, HIGH); delay(200); digitalWrite(stepPin, LOW); delay(200); digitalWrite(dirPin, LOW); digitalWrite(stepPin, HIGH); delay(200); digitalWrite(stepPin, LOW); delay(200);

Solution

1. Step 1: Set direction before stepping

   Each loop sets direction pin before sending step pulses to control rotation direction.

2. Step 2: Send exact number of step pulses

   Each for loop sends 200 pulses with HIGH then LOW signals and delays for timing.

3. Step 3: Verify code correctness

   for(int i=0; i<200; i++) { digitalWrite(dirPin, HIGH); digitalWrite(stepPin, HIGH); delay(1); digitalWrite(stepPin, LOW); delay(1); } for(int i=0; i<200; i++) { digitalWrite(dirPin, LOW); digitalWrite(stepPin, HIGH); delay(1); digitalWrite(stepPin, LOW); delay(1); } correctly sets direction inside each loop and sends 200 pulses per direction.

4. Final Answer:

   for(int i=0; i<200; i++) { digitalWrite(dirPin, HIGH); digitalWrite(stepPin, HIGH); delay(1); digitalWrite(stepPin, LOW); delay(1); } for(int i=0; i<200; i++) { digitalWrite(dirPin, LOW); digitalWrite(stepPin, HIGH); delay(1); digitalWrite(stepPin, LOW); delay(1); } -> Option A

5. Quick Check:

   Set direction before stepping, send 200 pulses each way [OK]

Hint: Set direction before loop, pulse stepPin HIGH then LOW 200 times [OK]

Common Mistakes:

• Setting direction inside step pulse loop incorrectly
• Using delay as step count instead of pulse count
• Not toggling stepPin LOW after HIGH