Landing and disarming in Drone Programming - Mini Project: Build & Apply

Landing and disarming

📖 Scenario: You are programming a drone that needs to land safely and then turn off its motors to save power. This is important after completing a flight mission.

🎯 Goal: You will write a simple program to make the drone land and then disarm its motors.

📋 What You'll Learn

Create a variable called altitude with the starting height of the drone.

Create a variable called landing_height to represent the height at which the drone should stop descending.

Use a while loop to reduce the altitude until it reaches landing_height.

After landing, set a variable called motors_armed to False to disarm the drone.

Print the final altitude and the motors status.

💡 Why This Matters

🌍 Real World

Drones must land safely and turn off motors to save battery and avoid accidents.

💼 Career

Understanding how to control drone states and use loops is essential for drone programming and robotics jobs.

1

Set the initial altitude

Create a variable called altitude and set it to 100 to represent the drone's starting height in meters.

Drone Programming

# Create a variable called altitude and set it to 100
# Your code here

Hint

Use a simple assignment like altitude = 100.

2

Set the landing height

Create a variable called landing_height and set it to 0 to represent the ground level where the drone should stop descending.

Drone Programming

altitude = 100
# Create a variable called landing_height and set it to 0
# Your code here

Hint

Set landing_height to zero because the ground is at height zero.

3

Land the drone by lowering altitude

Use a while loop with the condition altitude > landing_height. Inside the loop, decrease altitude by 10 each time to simulate the drone descending.

Drone Programming

altitude = 100
landing_height = 0
# Use a while loop to lower altitude by 10 until it reaches landing_height
# Your code here

Hint

Use while altitude > landing_height: and inside reduce altitude by 10 with altitude -= 10.

4

Disarm motors and print status

Create a variable called motors_armed and set it to False to disarm the drone after landing. Then print the final altitude and the motors_armed status.

Drone Programming

altitude = 100
landing_height = 0
while altitude > landing_height:
    altitude -= 10
# Set motors_armed to False and print altitude and motors_armed
# Your code here

Hint

After the loop, set motors_armed = False and print both altitude and motors_armed.

Practice

1. What is the main purpose of disarm() in drone programming?

easy

A. To increase the drone's speed

B. To make the drone take off automatically

C. To stop the drone's motors and prevent propeller movement

D. To change the drone's flight path

Solution

1. Step 1: Understand the function of disarm()

   The disarm() function is used to stop the drone's motors, which stops the propellers from spinning.

2. Step 2: Compare with other options

   Taking off, increasing speed, or changing flight path are not related to disarming.

3. Final Answer:

   To stop the drone's motors and prevent propeller movement -> Option C

4. Quick Check:

   Disarm = stop motors [OK]

Hint: Disarm always means stop motors and propellers [OK]

Common Mistakes:

• Confusing disarm with takeoff
• Thinking disarm changes flight path
• Assuming disarm increases speed

2. Which of the following is the correct syntax to land a drone using a function named land()?

easy

A. land()

B. land[]

C. land{}

D. land;

Solution

1. Step 1: Recall function call syntax

   In most programming languages, calling a function uses parentheses after the function name, like land().

2. Step 2: Check other options

   Square brackets, curly braces, or semicolons alone are not valid for calling functions.

3. Final Answer:

   land() -> Option A

4. Quick Check:

   Function call = name() [OK]

Hint: Functions need parentheses to run [OK]

Common Mistakes:

• Using brackets [] instead of parentheses ()
• Adding semicolon without parentheses
• Using curly braces {} for function calls

3. What will be the output of this code snippet?

drone.arm()
drone.takeoff()
drone.land()
drone.disarm()
print(drone.status)

Assuming status shows 'disarmed' after disarming.

medium

A. armed

B. flying

C. landed

D. disarmed

Solution

1. Step 1: Follow the code steps

   The drone is first armed, then takes off, then lands, and finally disarms.

2. Step 2: Understand status after disarm()

   After calling disarm(), the drone's status changes to 'disarmed'.

3. Final Answer:

   disarmed -> Option D

4. Quick Check:

   Status after disarm() = disarmed [OK]

Hint: Disarm sets status to 'disarmed' after landing [OK]

Common Mistakes:

• Assuming status stays 'flying' after land()
• Confusing 'landed' with 'disarmed'
• Ignoring the effect of disarm() on status

4. Identify the error in this drone landing and disarming code:

drone.land
safety = drone.disarm()

medium

A. Missing parentheses after land function call

B. Using assignment instead of comparison

C. Incorrect variable name 'safety'

D. Disarm should be called before land

Solution

1. Step 1: Check function call syntax

   The code uses drone.land without parentheses, so the function is not called.

2. Step 2: Verify order and variables

   Assigning drone.disarm() to safety is valid, and disarm after land is correct.

3. Final Answer:

   Missing parentheses after land function call -> Option A

4. Quick Check:

   Function calls need () [OK]

Hint: Always add () to call functions [OK]

Common Mistakes:

• Forgetting parentheses on function calls
• Thinking disarm must come before land
• Confusing assignment with comparison

5. You want to safely end a drone flight by landing and then disarming. Which code sequence correctly ensures the drone lands before disarming?

hard

A. drone.disarm()
drone.land()

B. drone.land()
drone.disarm()

C. drone.land()
drone.land()
drone.disarm()

D. drone.disarm()
drone.disarm()
drone.land()

Solution

1. Step 1: Understand safe landing sequence

   The drone must land first to touch the ground safely before motors stop.

2. Step 2: Check code order

   drone.land() drone.disarm() calls land() first, then disarm(), which is correct.

3. Final Answer:

   drone.land() followed by drone.disarm() -> Option B

4. Quick Check:

   Land before disarm = drone.land() drone.disarm() [OK]

Hint: Always land before disarming motors [OK]

Common Mistakes:

• Disarming before landing causing unsafe stop
• Repeating land unnecessarily
• Calling disarm multiple times before landing