Drone components overview in Drone Programming - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of sensor data reading code

What is the output of this code that reads and prints the altitude sensor data?

Drone Programming

class AltitudeSensor:
    def __init__(self):
        self.altitude = 100  # meters
    def read(self):
        return self.altitude

sensor = AltitudeSensor()
print(f"Altitude: {sensor.read()} meters")

A Altitude: None meters

B Altitude: 0 meters

C Altitude: 100 meters

D Error: AttributeError

💡 Hint

Look at the value stored in the altitude attribute and what the read method returns.

The AltitudeSensor class sets altitude to 100 in the constructor. The read method returns this value. So the print statement outputs 'Altitude: 100 meters'.

🧠 Conceptual

intermediate

Purpose of the flight controller

Which option best describes the main role of the flight controller in a drone?

A It provides GPS location data only.

B It processes sensor data and controls motors to stabilize and navigate the drone.

C It charges the drone's battery during flight.

D It captures photos and videos during flight.

💡 Hint

Think about what part controls the drone's movement and balance.

The flight controller is the brain that reads sensors and adjusts motors to keep the drone stable and follow commands.

🔧 Debug

advanced

Identify the error in motor control code

What error will this motor control code produce when run?

Drone Programming

class Motor:
    def __init__(self, id):
        self.id = id
        self.speed = 0
    def set_speed(self, speed):
        if speed < 0 or speed > 100:
            raise ValueError("Speed must be 0-100")
        self.speed = speed

motor = Motor(1)
motor.set_speed(120)
print(motor.speed)

A 0

B 120

C AttributeError: 'Motor' object has no attribute 'speed'

D ValueError: Speed must be 0-100

💡 Hint

Check the set_speed method and the value passed to it.

The set_speed method raises a ValueError if speed is outside 0-100. Since 120 is passed, it raises the error.

📝 Syntax

advanced

Syntax error in GPS data parsing

Which option contains the correct syntax to parse GPS coordinates from a dictionary?

Drone Programming

gps_data = {'lat': 40.7128, 'lon': -74.0060}

# Choose the correct way to extract latitude and longitude

A latitude, longitude = gps_data['lat'], gps_data['lon']

B latitude, longitude = gps_data.lat, gps_data.lon

C latitude, longitude = gps_data['lat'; 'lon']

D latitude, longitude = gps_data.get('lat'), gps_data.get('longitude')

💡 Hint

Remember how to access dictionary values by keys.

Option A correctly accesses dictionary values by keys. Option A uses dot notation which is invalid for dict. Option A has wrong syntax with semicolon. Option A tries to get 'longitude' key which does not exist.

🚀 Application

expert

Calculate total thrust from motor speeds

Given this code snippet, what is the total thrust output printed?

Drone Programming

class Motor:
    def __init__(self, id):
        self.id = id
        self.speed = 0
    def set_speed(self, speed):
        self.speed = speed
    def thrust(self):
        return self.speed * 0.5

motors = [Motor(i) for i in range(4)]
speeds = [80, 90, 85, 95]
for m, s in zip(motors, speeds):
    m.set_speed(s)
total_thrust = sum(m.thrust() for m in motors)
print(f"Total thrust: {total_thrust}")

A Total thrust: 175.0

B Total thrust: 175.5

C Total thrust: 175

D Total thrust: 350.0

💡 Hint

Calculate thrust for each motor and add them up carefully.

Each motor's thrust is speed * 0.5. Speeds are 80,90,85,95. Thrusts: 40,45,42.5,47.5. Sum is 175.0.

Practice

1. Which component of a drone is primarily responsible for controlling its flight and processing sensor data?

easy

A. Motor

B. Battery

C. Camera

D. Flight controller

Solution

1. Step 1: Understand the role of the flight controller

   The flight controller acts like the brain of the drone, managing flight and sensor data.

2. Step 2: Compare with other components

   Batteries provide power, motors move the drone, and cameras capture images, but do not control flight.

3. Final Answer:

   Flight controller -> Option D

4. Quick Check:

   Flight controller = brain of drone [OK]

Hint: Flight controller = drone's brain controlling flight [OK]

Common Mistakes:

• Confusing battery with controller
• Thinking motors control flight logic
• Assuming camera controls flight

2. Which of the following is the correct way to declare a motor speed variable in a drone program using Python?

easy

A. motorSpeed := 100

B. motor-speed = 100

C. motorSpeed = 100

D. motor speed = 100

Solution

1. Step 1: Check Python variable naming rules

   Variable names cannot have spaces or hyphens; they can use letters, numbers, and underscores.

2. Step 2: Analyze each option

   motorSpeed = 100 uses camelCase without spaces or hyphens, which is valid. motor-speed = 100 uses a hyphen, invalid. motor speed = 100 has a space, invalid. motorSpeed := 100 uses walrus operator incorrectly for assignment.

3. Final Answer:

   motorSpeed = 100 -> Option C

4. Quick Check:

   Valid variable names have no spaces or hyphens [OK]

Hint: Variable names: no spaces or hyphens, use letters/numbers/underscores [OK]

Common Mistakes:

• Using hyphens in variable names
• Including spaces in variable names
• Misusing walrus operator for assignment

3. What will be the output of this Python code snippet simulating battery check?

battery_level = 75
if battery_level >= 50:
    print('Battery sufficient')
else:
    print('Battery low')

medium

A. Battery low

B. Battery sufficient

C. SyntaxError

D. No output

Solution

1. Step 1: Evaluate the battery_level condition

   The variable battery_level is 75, which is greater than or equal to 50.

2. Step 2: Determine which print statement runs

   Since 75 >= 50 is true, the code prints 'Battery sufficient'.

3. Final Answer:

   Battery sufficient -> Option B

4. Quick Check:

   75 >= 50 means battery sufficient [OK]

Hint: Check if battery_level >= 50 to decide output [OK]

Common Mistakes:

• Confusing comparison operators
• Ignoring indentation causing errors
• Assuming else runs when condition is true

4. Identify the error in this drone motor control code snippet:

def set_motor_speed(speed):
    if speed < 0 or speed > 100:
        print('Invalid speed')
    else
        print(f'Speed set to {speed}')

set_motor_speed(50)

medium

A. Missing colon after else

B. Incorrect function name

C. Invalid comparison operators

D. Wrong print statement syntax

Solution

1. Step 1: Check syntax after else statement

   In Python, the else statement must end with a colon (:).

2. Step 2: Identify the missing colon

   The else line lacks a colon, causing a syntax error.

3. Final Answer:

   Missing colon after else -> Option A

4. Quick Check:

   else must end with ':' in Python [OK]

Hint: Always put ':' after else in Python [OK]

Common Mistakes:

• Forgetting colon after else
• Misnaming functions
• Using wrong comparison signs

5. You want to program a drone to take a photo only if the battery level is above 30% and the camera is ready. Which Python condition correctly checks this before taking a photo?

battery_level = 45
camera_ready = True

if ???:
    print('Taking photo')
else:
    print('Cannot take photo')

hard

A. battery_level > 30 and camera_ready == True

B. battery_level > 30 or camera_ready == False

C. battery_level <= 30 and camera_ready

D. battery_level >= 30 and not camera_ready

Solution

1. Step 1: Understand the condition requirements

   The drone should take a photo only if battery_level is above 30 and camera is ready (True).

2. Step 2: Analyze each option

   battery_level > 30 and camera_ready == True correctly uses 'and' to require both conditions true. battery_level > 30 or camera_ready == False uses 'or' and wrong camera_ready check. battery_level <= 30 and camera_ready checks battery_level less or equal 30, wrong. battery_level >= 30 and not camera_ready requires camera not ready, wrong.

3. Final Answer:

   battery_level > 30 and camera_ready == True -> Option A

4. Quick Check:

   Both battery > 30 and camera ready needed [OK]

Hint: Use 'and' to require both battery and camera ready [OK]

Common Mistakes:

• Using 'or' instead of 'and'
• Checking wrong battery comparison
• Negating camera_ready incorrectly