RC signal loss failsafe in Drone Programming - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to check if the RC signal is lost.

Drone Programming

if rc_signal_strength [1] threshold:
    activate_failsafe()

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

A>

B<=

C!=

D==

Attempts:

3 left

💡 Hint

Common Mistakes

Using '>' instead of '<=' causes failsafe to never activate.

The failsafe activates when the RC signal strength is less than or equal to the threshold.

2fill in blank

medium

Complete the code to set the drone to hover mode during signal loss.

Drone Programming

if rc_signal_lost:
    drone_mode = [1]

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

A"manual"

B"land"

C"return_home"

D"hover"

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing 'land' might cause sudden landing, which is not always safe.

Hover mode keeps the drone stable and in place during signal loss.

3fill in blank

hard

Fix the error in the failsafe activation condition.

Drone Programming

if rc_signal_strength [1] threshold:
    activate_failsafe()

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

A<

B!=

C>=

D==

Attempts:

3 left

💡 Hint

Common Mistakes

Using '>=' causes failsafe to activate incorrectly.

The failsafe should activate when the signal strength is less than the threshold, not greater or equal.

4fill in blank

hard

Fill both blanks to create a dictionary mapping failsafe modes to actions.

Drone Programming

failsafe_actions = {"hover": [1], "land": [2]

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

Astabilize_drone

Binitiate_landing

Creturn_to_home

Dsend_alert

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping actions causes wrong behavior during failsafe.

'hover' mode calls stabilize_drone(), 'land' mode calls initiate_landing().

5fill in blank

hard

Fill all three blanks to complete the failsafe check and response.

Drone Programming

if rc_signal_strength [1] threshold:
    mode = [2]
    failsafe_actions[mode][3]

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

A<=

B"hover"

C()

D==

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting parentheses causes no function call.

The code checks if signal is less or equal to threshold, sets mode to 'hover', then calls the corresponding action function.

Practice

1.

What is the main purpose of an RC signal loss failsafe in drone programming?

easy

A. To keep the drone safe by triggering automatic actions when the remote control signal is lost

B. To increase the drone's speed during flight

C. To change the drone's color based on signal strength

D. To disable the drone's camera when the battery is low

Solution

1. Step 1: Understand the role of failsafe

   The failsafe activates when the drone loses connection with the remote control to prevent accidents.

2. Step 2: Identify the correct purpose

   It triggers automatic actions like hovering or returning home to keep the drone safe.

3. Final Answer:

   To keep the drone safe by triggering automatic actions when the remote control signal is lost -> Option A

4. Quick Check:

   Failsafe = safety trigger on signal loss [OK]

Hint: Failsafe acts when signal is lost to protect drone [OK]

Common Mistakes:

• Confusing failsafe with speed control
• Thinking failsafe changes drone color
• Assuming failsafe disables camera

2.

Which of the following code snippets correctly sets a failsafe action to make the drone hover when RC signal is lost?

if rc_signal_lost:
    drone.____()

easy

A. return_home

B. hover

C. land_immediately

D. increase_speed

Solution

1. Step 1: Identify the correct failsafe action for hovering

   The action to keep the drone in place is called 'hover'.

2. Step 2: Match the method name

   Using drone.hover() will make the drone stay in the air safely when signal is lost.

3. Final Answer:

   hover -> Option B

4. Quick Check:

   Hover = stay still on signal loss [OK]

Hint: Hover means stay still; use drone.hover() for failsafe [OK]

Common Mistakes:

• Choosing return_home which moves drone away
• Selecting land_immediately which lands drone
• Picking increase_speed which is unsafe

3.

What will be the output of the following code snippet when rc_signal_lost is True?

rc_signal_lost = True

if rc_signal_lost:
    action = 'return_home'
else:
    action = 'normal_flight'

print(action)

medium

A. return_home

B. normal_flight

C. None

D. SyntaxError

Solution

1. Step 1: Check the value of rc_signal_lost

   rc_signal_lost is True, so the if condition is met.

2. Step 2: Determine the assigned action

   Since condition is True, action is set to 'return_home'.

3. Final Answer:

   return_home -> Option A

4. Quick Check:

   True condition sets action = return_home [OK]

Hint: True condition triggers return_home action [OK]

Common Mistakes:

• Confusing True with False branch
• Expecting syntax error due to indentation
• Thinking print outputs None

4.

Find the error in this failsafe code snippet and choose the correct fix:

if rc_signal_lost = True:
    drone.hover()

medium

A. Change drone.hover() to drone.land()

B. Add a colon ':' after drone.hover()

C. Remove the if statement entirely

D. Change '=' to '==' in the if condition

Solution

1. Step 1: Identify the syntax error in the if condition

   The code uses '=' which is assignment, not comparison, inside the if condition.

2. Step 2: Correct the comparison operator

   Replace '=' with '==' to properly check if rc_signal_lost is True.

3. Final Answer:

   Change '=' to '==' in the if condition -> Option D

4. Quick Check:

   Use '==' for comparison in if statements [OK]

Hint: Use '==' to compare, '=' assigns value [OK]

Common Mistakes:

• Using '=' instead of '==' in conditions
• Adding colon after function call instead of if
• Removing if statement breaks logic

5.

You want to program a failsafe that makes the drone return home if the RC signal is lost for more than 5 seconds, otherwise it should hover. Which code snippet correctly implements this logic?

signal_lost_time = 6  # seconds

if rc_signal_lost:
    if signal_lost_time > 5:
        drone.return_home()
    else:
        drone.hover()

hard

A. The code should call drone.land() instead of drone.hover()

B. The code should use 'signal_lost_time >= 5' instead of '>'

C. The code correctly implements the failsafe logic

D. The code is missing an else for rc_signal_lost being False

Solution

1. Step 1: Analyze the nested if conditions

   The outer if checks if signal is lost, inner if checks if lost time is more than 5 seconds.

2. Step 2: Verify actions for each condition

   If lost time > 5, drone returns home; else it hovers. This matches the requirement.

3. Final Answer:

   The code correctly implements the failsafe logic -> Option C

4. Quick Check:

   Nested if matches time check and actions [OK]

Hint: Nested if handles time check and actions correctly [OK]

Common Mistakes:

• Using >= instead of > changes timing slightly
• Replacing hover with land changes behavior
• Ignoring else for rc_signal_lost is acceptable here