Why motor control is needed in Arduino - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to start the motor by setting the pin HIGH.

Arduino

digitalWrite(motorPin, [1]);

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

ALOW

BINPUT

CHIGH

DOUTPUT

Attempts:

3 left

💡 Hint

Common Mistakes

Using LOW instead of HIGH to start the motor.

Setting the motor pin to HIGH turns the motor on by providing voltage.

2fill in blank

medium

Complete the code to set the motor pin as an output.

Arduino

pinMode(motorPin, [1]);

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

AOUTPUT

BINPUT

CINPUT_PULLUP

DANALOG

Attempts:

3 left

💡 Hint

Common Mistakes

Setting pinMode to INPUT instead of OUTPUT.

To control a motor, the pin must be set as OUTPUT to send signals.

3fill in blank

hard

Fix the error in the code to stop the motor by setting the pin LOW.

Arduino

digitalWrite(motorPin, [1]);

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

AOUTPUT

BHIGH

CINPUT

DLOW

Attempts:

3 left

💡 Hint

Common Mistakes

Using HIGH instead of LOW to stop the motor.

Setting the motor pin to LOW stops the motor by cutting off voltage.

4fill in blank

hard

Fill both blanks to control motor speed using PWM.

Arduino

analogWrite(motorPin, [1]); // speed value between 0 and [2]

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

A255

B100

C0

D1023

Attempts:

3 left

💡 Hint

Common Mistakes

Using 1023 which is for analogRead, not analogWrite.

Speed values start at 0 (off) and go up to 255 for full speed in Arduino PWM.

5fill in blank

hard

Fill all three blanks to create a dictionary of motor speeds for different directions.

Arduino

motorSpeeds = [1]: 255, [2]: 0, [3]: 128}

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

A"forward"

B"stop"

C"half"

D"backward"

Attempts:

3 left

💡 Hint

Common Mistakes

Using numbers as keys instead of strings.

This dictionary maps directions to speed values: full speed forward, stop, and half speed.

Practice

1. Why is motor control important in Arduino projects?

easy

A. It automatically fixes motor hardware issues.

B. It makes the motor run only at full speed.

C. It prevents the motor from ever stopping.

D. It allows you to control the speed and direction of the motor.

Solution

1. Step 1: Understand motor control purpose

   Motor control lets you decide how fast and which way a motor spins.

2. Step 2: Compare options with motor control function

   Only It allows you to control the speed and direction of the motor. correctly states speed and direction control, which is the main reason for motor control.

3. Final Answer:

   It allows you to control the speed and direction of the motor. -> Option D

4. Quick Check:

   Motor control = speed and direction control [OK]

Hint: Motor control means managing speed and direction [OK]

Common Mistakes:

• Thinking motor control only runs motor at full speed
• Assuming motor control fixes hardware automatically
• Believing motor control prevents motor from stopping

2. Which Arduino pin type is typically used to control motor speed?

easy

A. Analog pin

B. PWM pin

C. Digital pin

D. Ground pin

Solution

1. Step 1: Identify pin types for motor control

   Speed control uses PWM (Pulse Width Modulation) pins to vary power to the motor.

2. Step 2: Match pin type to speed control

   Only PWM pins can change motor speed by adjusting power pulses.

3. Final Answer:

   PWM pin -> Option B

4. Quick Check:

   Speed control = PWM pin [OK]

Hint: Speed needs PWM pins, not just digital [OK]

Common Mistakes:

• Choosing digital pins for speed control
• Confusing analog pins with PWM pins
• Selecting ground pin by mistake

3. What will this Arduino code do?

analogWrite(5, 128);
digitalWrite(4, HIGH);

Assuming pin 5 controls speed and pin 4 controls direction of a motor.

medium

A. Motor runs at half speed forward.

B. Motor runs at full speed backward.

C. Motor stops immediately.

D. Motor runs at half speed backward.

Solution

1. Step 1: Analyze analogWrite on pin 5

   analogWrite(5, 128) sets PWM to about half power (128 out of 255), so motor speed is half.

2. Step 2: Analyze digitalWrite on pin 4

   digitalWrite(4, HIGH) sets direction pin HIGH, which we assume means forward direction.

3. Final Answer:

   Motor runs at half speed forward. -> Option A

4. Quick Check:

   Speed half + direction forward = half speed forward [OK]

Hint: PWM 128 means half speed; HIGH usually means forward [OK]

Common Mistakes:

• Assuming analogWrite 128 is full speed
• Confusing HIGH with backward direction
• Thinking motor stops with these commands

4. Find the error in this motor control code snippet:

pinMode(3, OUTPUT);
digitalWrite(3, 255);

medium

A. digitalWrite cannot take 255 as a value.

B. pinMode should be INPUT, not OUTPUT.

C. pin 3 cannot be used for motor control.

D. digitalWrite needs to be called before pinMode.

Solution

1. Step 1: Check digitalWrite parameters

   digitalWrite only accepts HIGH or LOW, not numeric values like 255.

2. Step 2: Validate pinMode and call order

   pinMode(3, OUTPUT) is correct and must be called before digitalWrite, which is done here.

3. Final Answer:

   digitalWrite cannot take 255 as a value. -> Option A

4. Quick Check:

   digitalWrite = HIGH or LOW only [OK]

Hint: digitalWrite only uses HIGH or LOW [OK]

Common Mistakes:

• Using numbers instead of HIGH/LOW in digitalWrite
• Switching pinMode to INPUT incorrectly
• Calling digitalWrite before pinMode

5. You want to control a motor's speed and direction using Arduino. Which combination of pins should you use?

hard

A. Two digital pins for speed and direction

B. Two PWM pins both for speed control

C. One PWM pin for speed and one digital pin for direction

D. One analog pin for direction and one digital pin for speed

Solution

1. Step 1: Understand pin roles for motor control

   Speed is controlled by PWM pins to vary power; direction is controlled by digital pins to set HIGH or LOW.

2. Step 2: Evaluate each option

   One PWM pin for speed and one digital pin for direction correctly pairs one PWM pin for speed and one digital pin for direction. Others misuse pin types.

3. Final Answer:

   One PWM pin for speed and one digital pin for direction -> Option C

4. Quick Check:

   Speed = PWM, Direction = digital [OK]

Hint: Speed needs PWM, direction needs digital pin [OK]

Common Mistakes:

• Using digital pins for speed control
• Using analog pins for direction
• Trying to control both speed and direction with PWM only