Stepper motor basics in Arduino - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to include the Stepper library.

Arduino

#include <[1]>

Drag options to blanks, or click blank then click option'

AWire.h

BServo.h

CStepper.h

DSPI.h

Attempts:

3 left

💡 Hint

Common Mistakes

Including Servo.h instead of Stepper.h

Forgetting the angle brackets <>

The Stepper library controls stepper motors. Including Stepper.h allows us to use its functions.

2fill in blank

medium

Complete the code to create a Stepper object with 200 steps per revolution.

Arduino

Stepper myStepper([1], 8, 9, 10, 11);

Drag options to blanks, or click blank then click option'

A100

B200

C400

D50

Attempts:

3 left

💡 Hint

Common Mistakes

Using 100 or 400 steps which may not match the motor

Confusing pin numbers with steps

Most common stepper motors have 200 steps per revolution. This number tells the library how many steps to make a full turn.

3fill in blank

hard

Fix the error in setting the motor speed to 60 RPM.

Arduino

myStepper.[1](60);

Drag options to blanks, or click blank then click option'

Arpm

Bspeed

CmoveSpeed

DsetSpeed

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'speed' as a function instead of 'setSpeed'

Trying to set speed directly as a variable

The correct function to set speed in RPM is setSpeed(). Other options are invalid or do not exist.

4fill in blank

hard

Fill both blanks to move the motor 100 steps forward.

Arduino

myStepper.[1]([2]);

Drag options to blanks, or click blank then click option'

Astep

Bmove

C100

D200

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'move' instead of 'step'

Using 200 steps instead of 100

The step() function moves the motor a number of steps. Here, 100 steps moves it forward.

5fill in blank

hard

Fill all three blanks to create a Stepper object with 4 control pins and 100 steps per revolution.

Arduino

[1] [2]([3], 6, 7, 8, 9);

Drag options to blanks, or click blank then click option'

A100

B4

CStepper

Dmotor

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping the order of steps and pins

Using variable names instead of class name

The first blank is the class name Stepper. The second is the object name motor. The third is the number of steps 100. Using four pins indicates 4 control pins.

Practice

1. What is the main advantage of using a stepper motor in Arduino projects?

easy

A. It moves in precise, small steps for accurate positioning.

B. It runs faster than all other motors.

C. It uses less power than a servo motor.

D. It requires no programming to control.

Solution

1. Step 1: Understand stepper motor movement

   Stepper motors move in small, fixed steps, allowing precise control of position.

2. Step 2: Compare with other motors

   Unlike regular motors, stepper motors do not rotate freely but in exact increments.

3. Final Answer:

   It moves in precise, small steps for accurate positioning. -> Option A

4. Quick Check:

   Stepper motor precision = Accurate small steps [OK]

Hint: Stepper motors move in fixed steps for precision [OK]

Common Mistakes:

• Thinking stepper motors run faster than all motors
• Assuming no programming is needed
• Confusing power usage with motor type

2. Which of the following is the correct way to create a Stepper object in Arduino code?

easy

A. Stepper myStepper = new Stepper(pin1, pin2, pin3, pin4);

B. Stepper myStepper = Stepper(stepsPerRevolution, pin1, pin2);

C. Stepper myStepper(stepsPerRevolution);

D. Stepper myStepper(stepsPerRevolution, pin1, pin2, pin3, pin4);

Solution

1. Step 1: Recall Stepper constructor syntax

   The Stepper library requires the number of steps per revolution and four control pins.

2. Step 2: Match syntax with options

   Stepper myStepper(stepsPerRevolution, pin1, pin2, pin3, pin4); correctly uses Stepper(stepsPerRevolution, pin1, pin2, pin3, pin4) to create the object.

3. Final Answer:

   Stepper myStepper(stepsPerRevolution, pin1, pin2, pin3, pin4); -> Option D

4. Quick Check:

   Stepper constructor needs steps and 4 pins [OK]

Hint: Stepper needs steps and 4 pins in constructor [OK]

Common Mistakes:

• Using only 2 pins instead of 4
• Trying to use 'new' keyword in Arduino
• Omitting steps per revolution

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

Stepper myStepper(200, 8, 9, 10, 11);
void setup() {
  myStepper.setSpeed(60);
}
void loop() {
  myStepper.step(100);
  delay(1000);
  myStepper.step(-100);
  delay(1000);
}

medium

A. The motor rotates 100 steps forward, pauses 1 second, then 100 steps backward, pauses 1 second, and repeats.

B. The motor rotates continuously forward without stopping.

C. The motor rotates 100 steps backward only once.

D. The code will cause a compilation error due to missing pinMode setup.

Solution

1. Step 1: Analyze step commands in loop()

   The code commands the motor to move 100 steps forward, then 100 steps backward, each followed by a 1-second delay.

2. Step 2: Understand loop repetition

   Since this is in loop(), the forward and backward steps repeat indefinitely with pauses.

3. Final Answer:

   The motor rotates 100 steps forward, pauses 1 second, then 100 steps backward, pauses 1 second, and repeats. -> Option A

4. Quick Check:

   Stepper steps forward and backward with delay [OK]

Hint: Positive steps move forward; negative steps move backward [OK]

Common Mistakes:

• Thinking motor runs continuously forward
• Assuming missing pinMode causes error
• Ignoring the delay pauses

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

Stepper myStepper(200, 8, 9, 10, 11);
void setup() {
  myStepper.setSpeed(60);
}
void loop() {
  myStepper.step(50);
  delay(500);
}

medium

A. The stepper motor pins are not set as outputs using pinMode.

B. There is no error; the code will run correctly.

C. The step() function requires a negative number to move forward.

D. The setSpeed() function is called in setup(), which is incorrect.

Solution

1. Step 1: Check pinMode necessity for Stepper library

   The Stepper library internally handles pin modes, so explicit pinMode calls are not required.

2. Step 2: Verify setSpeed and step usage

   Calling setSpeed() in setup() and step() in loop() is correct usage for controlling speed and movement.

3. Final Answer:

   There is no error; the code will run correctly. -> Option B

4. Quick Check:

   Stepper library manages pins; code is valid [OK]

Hint: Stepper library sets pins automatically; no pinMode needed [OK]

Common Mistakes:

• Adding unnecessary pinMode calls
• Misunderstanding setSpeed() placement
• Confusing step() sign for direction

5. You want to rotate a stepper motor exactly one full revolution at 120 RPM using Arduino's Stepper library. The motor has 200 steps per revolution. Which code snippet correctly achieves this in the loop() function?

hard

A. myStepper.setSpeed(60);
myStepper.step(200);

B. myStepper.setSpeed(120);
myStepper.step(100);

C. myStepper.setSpeed(120);
myStepper.step(200);

D. myStepper.setSpeed(120);
myStepper.step(-200);

Solution

1. Step 1: Calculate steps for one revolution

   The motor requires 200 steps for one full revolution.

2. Step 2: Set speed and steps correctly

   To rotate at 120 RPM, setSpeed(120) is correct, and step(200) moves one full revolution forward.

3. Final Answer:

   myStepper.setSpeed(120); myStepper.step(200); -> Option C

4. Quick Check:

   200 steps = 1 revolution; speed 120 RPM [OK]

Hint: Steps = motor steps/rev; speed = desired RPM [OK]

Common Mistakes:

• Using half the steps (100) for full revolution
• Setting speed lower than desired RPM
• Using negative steps when forward rotation needed