Command acknowledgment handling in Drone Programming - Mini Project: Build & Apply

Command acknowledgment handling

📖 Scenario: You are programming a drone to receive commands and confirm when each command is acknowledged. This helps ensure the drone safely follows instructions.

🎯 Goal: Build a simple program that stores commands, tracks which commands have been acknowledged, and prints the acknowledgment status.

📋 What You'll Learn

Create a dictionary with commands and their acknowledgment status

Add a variable to count acknowledged commands

Use a loop to update acknowledgment status for specific commands

Print the final acknowledgment status dictionary

💡 Why This Matters

🌍 Real World

Drones must confirm they received commands to avoid mistakes during flight.

💼 Career

Understanding command acknowledgment is important for programming safe and reliable autonomous drones.

1

Create the commands dictionary

Create a dictionary called commands with these exact entries: 'takeoff': False, 'move_forward': False, 'turn_left': False, 'land': False

Drone Programming

# Create the commands dictionary with initial acknowledgment status
# Your code here

Hint

Use a dictionary with command names as keys and False as initial values.

2

Add acknowledgment counter

Create a variable called ack_count and set it to 0 to count acknowledged commands

Drone Programming

commands = {'takeoff': False, 'move_forward': False, 'turn_left': False, 'land': False}
# Create acknowledgment counter
# Your code here

Hint

Just create a variable named ack_count and set it to zero.

3

Update acknowledgment status

Use a for loop with variable command to iterate over the list ['takeoff', 'land']. Inside the loop, set commands[command] to True and increase ack_count by 1

Drone Programming

commands = {'takeoff': False, 'move_forward': False, 'turn_left': False, 'land': False}
ack_count = 0
# Update acknowledgment status for 'takeoff' and 'land'
# Your code here

Hint

Loop over the list and update the dictionary and counter inside the loop.

4

Print acknowledgment status

Write a print statement to display the commands dictionary

Drone Programming

commands = {'takeoff': False, 'move_forward': False, 'turn_left': False, 'land': False}
ack_count = 0
for command in ['takeoff', 'land']:
    commands[command] = True
    ack_count += 1
# Print the commands dictionary
# Your code here

Hint

Use print(commands) to show the final acknowledgment status.

Practice

1.

What is the main purpose of command acknowledgment in drone programming?

easy

A. To confirm the drone received and understood the command

B. To increase the drone's flying speed

C. To recharge the drone's battery remotely

D. To change the drone's camera settings automatically

Solution

1. Step 1: Understand command acknowledgment

   Command acknowledgment means the drone sends back a message confirming it got the command.

2. Step 2: Identify the purpose

   This confirmation ensures the command was received and understood, which is critical for safe control.

3. Final Answer:

   To confirm the drone received and understood the command -> Option A

4. Quick Check:

   Command acknowledgment = Confirm command received [OK]

Hint: Acknowledgment means confirmation of command receipt [OK]

Common Mistakes:

• Confusing acknowledgment with drone speed control
• Thinking acknowledgment changes hardware settings
• Assuming acknowledgment recharges battery

2.

Which of the following code snippets correctly checks if a drone command acknowledgment is received?

if response == 'ACK':
    print('Command confirmed')
else:
    print('No confirmation')

easy

A. if response = 'ACK':

B. if response == 'ACK':

C. if response === 'ACK':

D. if response != 'ACK':

Solution

1. Step 1: Identify correct equality operator

   In Python, '==' checks if two values are equal, which is needed here.

2. Step 2: Review options

   '=' is assignment, '===' is not valid in Python, '!=' means not equal, so only '==' is correct.

3. Final Answer:

   if response == 'ACK': -> Option B

4. Quick Check:

   Equality check uses '==' in Python [OK]

Hint: Use '==' to compare values in Python conditions [OK]

Common Mistakes:

• Using single '=' instead of '==' for comparison
• Using '===' which is JavaScript syntax, not Python
• Confusing '!=' with equality check

3.

What will be the output of this code snippet handling drone command acknowledgment?

response = 'NACK'
if response == 'ACK':
    print('Command successful')
else:
    print('Command failed')

medium

A. Command successful

B. SyntaxError

C. Command failed

D. No output

Solution

1. Step 1: Check the response value

   The variable response is set to 'NACK', which means negative acknowledgment.

2. Step 2: Evaluate the if condition

   The condition checks if response equals 'ACK'. Since it is 'NACK', the else block runs.

3. Final Answer:

   Command failed -> Option C

4. Quick Check:

   response != 'ACK' triggers else [OK]

Hint: If response isn't 'ACK', else block runs [OK]

Common Mistakes:

• Assuming 'NACK' means success
• Expecting no output when else runs
• Confusing syntax error with logic error

4.

Identify the error in this drone command acknowledgment code snippet:

response = get_drone_response()
if response = 'ACK':
    print('Command confirmed')
else:
    print('No confirmation')

medium

A. No else block present

B. Missing parentheses in print statements

C. Incorrect function name 'get_drone_response'

D. Using '=' instead of '==' in the if condition

Solution

1. Step 1: Check the if condition syntax

   The condition uses '=' which assigns value, but comparison needs '=='.

2. Step 2: Verify other parts

   Print statements have parentheses, function name is assumed correct, else block exists.

3. Final Answer:

   Using '=' instead of '==' in the if condition -> Option D

4. Quick Check:

   Comparison uses '==' not '=' [OK]

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

Common Mistakes:

• Confusing assignment '=' with equality '=='
• Thinking print needs no parentheses in Python 3
• Assuming function name is wrong without context

5.

You want to send a command to a drone and wait for acknowledgment with a timeout of 5 seconds. Which approach correctly handles this?

import time

def send_command_with_ack(command):
    send_command(command)
    start = time.time()
    while time.time() - start < 5:
        response = get_drone_response()
        if response == 'ACK':
            return 'Success'
    return 'Timeout'

hard

A. The code waits up to 5 seconds for 'ACK', then returns 'Timeout' if none

B. The code immediately returns 'Timeout' without waiting

C. The code waits forever until 'ACK' is received

D. The code returns 'Success' without checking response

Solution

1. Step 1: Analyze the timeout loop

   The while loop runs while elapsed time is less than 5 seconds, checking for 'ACK'.

2. Step 2: Check return behavior

   If 'ACK' is received, returns 'Success'; if time exceeds 5 seconds without 'ACK', returns 'Timeout'.

3. Final Answer:

   The code waits up to 5 seconds for 'ACK', then returns 'Timeout' if none -> Option A

4. Quick Check:

   Timeout loop waits max 5 seconds for acknowledgment [OK]

Hint: Use time check loop to wait with timeout [OK]

Common Mistakes:

• Not implementing timeout, causing infinite wait
• Returning timeout immediately without waiting
• Ignoring response check before returning success