Stepper motor with driver module in Arduino - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Stepper Motor Basic Rotation Output

What will be the output behavior of the stepper motor when running this Arduino code snippet?

Arduino

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

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

void loop() {
  digitalWrite(stepPin, HIGH);
  delayMicroseconds(1000);
  digitalWrite(stepPin, LOW);
  delayMicroseconds(1000);
}

A The motor rotates back and forth repeatedly.

B The motor rotates continuously in one direction at a steady speed.

C The motor does not rotate because the step pin is never pulsed.

D The motor rotates continuously but changes direction every second.

💡 Hint

Look at how the step pin is pulsed and the direction pin is set once in setup.

The code sets the direction pin HIGH once, so the motor direction is fixed. The step pin is pulsed repeatedly with equal HIGH and LOW durations, causing continuous rotation in one direction.

🧠 Conceptual

intermediate

Understanding Stepper Motor Driver Pins

Which pin on a typical stepper motor driver module controls the rotation direction of the motor?

A Ground pin

B Enable pin

C Step pin

D Direction pin

💡 Hint

Think about which pin tells the motor which way to turn.

The direction pin controls the rotation direction by setting it HIGH or LOW. The step pin controls stepping pulses, enable pin turns the driver on/off, and ground is for electrical reference.

🔧 Debug

advanced

Identify the Error in Stepper Motor Speed Control Code

What error will occur when running this Arduino code to control stepper motor speed?

Arduino

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

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

void loop() {
  for (int i = 0; i < 200; i++) {
    digitalWrite(stepPin, HIGH);
    delay(1);
    digitalWrite(stepPin, LOW);
    delay(1);
  }
  delay(1000);
  delay(0);
}

A The code runs without error and rotates the motor 200 steps then pauses.

B The delay(0) causes a compile-time error because 0 is invalid.

C The motor will not rotate because the direction pin is never set HIGH.

D The motor rotates but the speed is too fast to control.

💡 Hint

Check if delay(0) is valid and what setting direction LOW means.

delay(0) is valid and just causes no delay. Direction LOW is a valid direction. The loop pulses the step pin 200 times with 1 ms delay each, rotating the motor 200 steps then pauses 1 second.

📝 Syntax

advanced

Find the Syntax Error in Stepper Motor Control Code

Which option contains the correct syntax to set the step pin HIGH and LOW with a 500 microsecond delay between?

A

digitalWrite(stepPin, HIGH);
delayMicroseconds(500);
digitalWrite(stepPin, LOW);
delayMicroseconds(500);

B

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;)WOL ,niPpets(etirWlatigid
;)005(sdnocesorciMyaled
;)HGIH ,niPpets(etirWlatigid

C

digitalWrite(stepPin, HIGH)
delayMicroseconds(500)
digitalWrite(stepPin, LOW)
delayMicroseconds(500)

D

digitalWrite(stepPin HIGH);
delayMicroseconds(500);
digitalWrite(stepPin LOW);
delayMicroseconds(500);

💡 Hint

Check for missing commas, semicolons, and parentheses.

Option A has correct syntax: commas separate arguments in digitalWrite, and semicolons terminate every statement. Option A misses semicolon after last delayMicroseconds(500). Option A misses commas after stepPin. Option A misses semicolons after each statement.

🚀 Application

expert

Calculate Steps for 90 Degree Rotation

A stepper motor has 200 steps per full revolution. Using a driver module, how many step pulses must be sent to rotate the motor shaft exactly 90 degrees?

A 25 steps

B 100 steps

C 50 steps

D 200 steps

💡 Hint

A full revolution is 360 degrees. Calculate the fraction for 90 degrees.

90 degrees is one quarter of 360 degrees. One quarter of 200 steps is 50 steps.