Servo angle positioning in Arduino - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the servo angle after this code runs?

Consider this Arduino code controlling a servo motor. What angle will the servo be set to after loop() runs once?

Arduino

 #include <Servo.h>
Servo myServo;

void setup() {
  myServo.attach(9);
  myServo.write(45);
}

void loop() {
  myServo.write(90);
  delay(1000);
  myServo.write(135);
  delay(1000);
  // loop ends here
}

A 135 degrees

B 45 degrees

C 90 degrees

D 0 degrees

💡 Hint

Remember the loop() function runs repeatedly. The last write() call sets the final angle before the loop restarts.

The loop() function sets the servo to 90 degrees, waits 1 second, then sets it to 135 degrees and waits 1 second. After that, the loop restarts. So the last angle set before the loop restarts is 135 degrees.

🧠 Conceptual

intermediate

Why do we use myServo.attach(pin) in Arduino servo control?

What is the main purpose of calling myServo.attach(pin) in an Arduino program controlling a servo?

A To calibrate the servo's speed

B To set the initial angle of the servo

C To power the servo motor from the Arduino

D To specify which pin the servo signal wire is connected to

💡 Hint

Think about how the Arduino knows where to send the control signal.

The attach() function tells the Arduino which pin will send the control pulses to the servo. It does not set angle, power, or speed.

🔧 Debug

advanced

Why does this servo code cause the servo to jitter?

Look at this Arduino code snippet. The servo jitters and does not hold a steady angle. What is the cause?

Arduino

#include <Servo.h>
Servo myServo;

void setup() {
  myServo.attach(10);
}

void loop() {
  for (int angle = 0; angle <= 180; angle += 10) {
    myServo.write(angle);
    delay(15);
  }
}

A The servo is not attached to the correct pin

B The delay is too short for the servo to reach the angle before changing

C The for loop should count down from 180 to 0

D The servo library is not included properly

💡 Hint

Think about how fast the servo can physically move and how often the angle changes.

The delay of 15 milliseconds is too short for the servo to reach the new angle before the next command. This causes jitter because the servo keeps receiving new positions too quickly.

📝 Syntax

advanced

Which option fixes the syntax error in this servo control code?

Find the option that corrects the syntax error in the following Arduino code:

#include <Servo.h>
Servo myServo;

void setup() {
  myServo.attach(9)
  myServo.write(90);
}

void loop() {
  // empty
}

A Add a semicolon after <code>myServo.attach(9)</code>

B Change <code>myServo.attach(9)</code> to <code>myServo.attach(9);;</code>

C Remove the semicolon after <code>myServo.write(90);</code>

D Add parentheses to <code>setup</code> like <code>setup();</code>

💡 Hint

Check the end of each statement for proper punctuation.

In Arduino (C++), each statement must end with a semicolon. The line myServo.attach(9) is missing a semicolon, causing a syntax error.

🚀 Application

expert

How many unique angles will this servo sweep cover?

This Arduino code sweeps a servo from 0 to 180 degrees in steps of 30 degrees. How many unique angles will the servo be set to during one full sweep?

Arduino

#include <Servo.h>
Servo myServo;

void setup() {
  myServo.attach(9);
}

void loop() {
  for (int angle = 0; angle <= 180; angle += 30) {
    myServo.write(angle);
    delay(500);
  }
  while(true) {}
}

A 4

B 6

C 7

D 5

💡 Hint

Count all values from 0 to 180 stepping by 30, including both ends.

The loop sets angles at 0, 30, 60, 90, 120, 150, and 180 degrees. That's 7 unique angles in total.