Battery failsafe in Drone Programming - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Battery failsafe trigger output

What will be the output of this drone battery monitoring code snippet when battery level is 15%?

Drone Programming

battery_level = 15
if battery_level < 20:
    print("Warning: Battery low! Initiate failsafe.")
else:
    print("Battery level normal.")

A Error: battery_level undefined

B Battery level normal.

C Warning: Battery low! Initiate failsafe.

D No output

💡 Hint

Check the condition comparing battery_level with 20.

Since battery_level is 15, which is less than 20, the if condition is true and the warning message is printed.

🧠 Conceptual

intermediate

Failsafe activation condition

Which battery level condition correctly activates the failsafe when battery is critically low?

A if battery_level >= 90:

B if battery_level > 10:

C if battery_level == 50:

D if battery_level <= 10:

💡 Hint

Failsafe should trigger at or below a critical low battery percentage.

Failsafe activates when battery is at or below 10%, so condition 'battery_level <= 10' is correct.

🔧 Debug

advanced

Identify the error in battery failsafe code

What error will this code produce when run? battery_level = 25 if battery_level < 20 print("Failsafe activated")

Drone Programming

battery_level = 25
if battery_level < 20
    print("Failsafe activated")

A SyntaxError: expected ':' after if condition

B No error, prints nothing

C IndentationError: unexpected indent

D NameError: battery_level not defined

💡 Hint

Check the syntax of the if statement.

The if statement is missing a colon ':' at the end of the condition line, causing a SyntaxError.

🚀 Application

advanced

Failsafe behavior with multiple battery checks

Given this code, what will be printed if battery_level is 18? battery_level = 18 if battery_level < 10: print("Critical battery! Land immediately.") elif battery_level < 20: print("Warning: Battery low. Prepare to land.") else: print("Battery level sufficient.")

Drone Programming

battery_level = 18
if battery_level < 10:
    print("Critical battery! Land immediately.")
elif battery_level < 20:
    print("Warning: Battery low. Prepare to land.")
else:
    print("Battery level sufficient.")

A Critical battery! Land immediately.

B Warning: Battery low. Prepare to land.

C Battery level sufficient.

D No output

💡 Hint

Check which condition matches battery_level 18 first.

18 is not less than 10, so first if is false. It is less than 20, so elif is true and prints the warning.

❓ Predict Output

expert

Failsafe loop with battery drain simulation

What is the final output of this code simulating battery drain and failsafe activation? battery_level = 25 while battery_level > 0: battery_level -= 7 if battery_level <= 10: print(f"Failsafe activated at {battery_level}% battery") break else: print("Battery drained without failsafe")

Drone Programming

battery_level = 25
while battery_level > 0:
    battery_level -= 7
    if battery_level <= 10:
        print(f"Failsafe activated at {battery_level}% battery")
        break
else:
    print("Battery drained without failsafe")

A Failsafe activated at 4% battery

B Failsafe activated at 11% battery

C Battery drained without failsafe

D Failsafe activated at -3% battery

💡 Hint

Trace battery_level changes each loop iteration.

battery_level decreases by 7 each loop: 25->18->11->4. At 4 (<=10), failsafe triggers and breaks loop.

Practice

1. What is the main purpose of a battery failsafe in drone programming?

easy

A. To prevent drone crashes by acting when battery is low

B. To increase the drone's speed automatically

C. To improve the camera quality during flight

D. To connect the drone to Wi-Fi networks

Solution

1. Step 1: Understand the battery failsafe concept and identify the correct purpose

   The battery failsafe is designed to protect the drone from running out of power mid-flight. Preventing crashes by triggering safe actions like landing or returning home when battery is low is the main goal.

2. Final Answer:

   To prevent drone crashes by acting when battery is low -> Option A

3. Quick Check:

   Failsafe = prevent crashes [OK]

Hint: Failsafe triggers on low battery to avoid crashes [OK]

Common Mistakes:

• Confusing failsafe with speed control
• Thinking it improves camera quality
• Assuming it manages Wi-Fi connections

2. Which of the following is the correct syntax to check if the battery level is below 20% in drone programming?

easy

A. if battery_level == 20:

B. if battery_level > 20:

C. if battery_level < 20:

D. if battery_level = 20:

Solution

1. Step 1: Identify the comparison operator and confirm syntax for less than

   The symbol '<' means less than, so 'battery_level < 20' checks if battery is below 20%. Using a single '=' is assignment, '==' is equality check, but we want less than, so '<' is correct.

2. Final Answer:

   if battery_level < 20: -> Option C

3. Quick Check:

   Less than 20% check = if battery_level < 20 [OK]

Hint: Use '<' to check if battery is below threshold [OK]

Common Mistakes:

• Using '=' instead of '<' for comparison
• Using '>' which checks above threshold
• Confusing '==' with less than operator

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

battery_level = 15
if battery_level < 20:
    action = 'Return to home'
else:
    action = 'Continue flying'
print(action)

medium

A. Continue flying

B. SyntaxError

C. No output

D. Return to home

Solution

1. Step 1: Check battery_level value, condition, and determine action

   battery_level is 15, which is less than 20, so the condition is true. Since condition is true, action is set to 'Return to home'. The else block is skipped.

2. Final Answer:

   Return to home -> Option D

3. Quick Check:

   battery_level 15 < 20 triggers 'Return to home' [OK]

Hint: Check condition true or false to pick output [OK]

Common Mistakes:

• Assuming else block runs when condition is true
• Confusing '<' with '>' operator
• Expecting syntax error from correct code

4. Identify the error in this battery failsafe code snippet:

if battery_level = 15:
    trigger_landing()

medium

A. Missing colon ':' after if statement

B. Using '=' instead of '==' in condition

C. Incorrect function name 'trigger_landing()'

D. battery_level should be a string

Solution

1. Step 1: Check if statement syntax and confirm other elements

   The '=' sign is used for assignment, not comparison. For comparison, '==' is needed. The colon ':' is present, function name looks valid, and battery_level should be a number, not string.

2. Final Answer:

   Using '=' instead of '==' in condition -> Option B

3. Quick Check:

   Use '==' to compare values in if [OK]

Hint: Use '==' for comparison, '=' is assignment [OK]

Common Mistakes:

• Confusing '=' with '==' in conditions
• Ignoring missing colon errors
• Assuming variable type must be string

5. You want your drone to automatically land if battery is below 15%, and return home if battery is between 15% and 25%. Which code snippet correctly implements this failsafe?

hard

A. if battery_level < 15:
land()
elif battery_level >= 15 and battery_level <= 25:
return_home()

B. if battery_level <= 15:
return_home()
elif battery_level > 15 and battery_level < 25:
land()

C. if battery_level > 15:
land()
elif battery_level < 25:
return_home()

D. if battery_level == 15:
land()
else:
return_home()

Solution

1. Step 1: Analyze battery level conditions and match to code options

   Battery below 15% means battery_level < 15 triggers landing. Between 15% and 25% means battery_level >= 15 and battery_level <= 25 triggers return home.
   if battery_level < 15:
   land()
   elif battery_level >= 15 and battery_level <= 25:
   return_home() correctly uses conditions. Others mix conditions or reverse actions.

2. Final Answer:

   if battery_level < 15: land() elif battery_level >= 15 and battery_level <= 25: return_home() -> Option A

3. Quick Check:

   Correct ranges and actions match if battery_level < 15: land() elif battery_level >= 15 and battery_level <= 25: return_home() [OK]

Hint: Check ranges carefully and match actions exactly [OK]

Common Mistakes:

• Swapping landing and return actions
• Using wrong comparison operators
• Not covering full battery range properly