Barometer for altitude in Drone Programming - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to read the current pressure from the barometer sensor.

Drone Programming

pressure = barometer.[1]()

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

Aread_pressure

Bcalibrate

Cstart

Dget_altitude

Attempts:

3 left

💡 Hint

Common Mistakes

Using get_altitude() instead of read_pressure()

Calling start() which initializes but does not read data

The method read_pressure() reads the current pressure value from the barometer sensor.

2fill in blank

medium

Complete the code to convert pressure to altitude using the barometer's method.

Drone Programming

altitude = barometer.[1](pressure)

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

Acalculate_altitude

Bread_altitude

Cmeasure_altitude

Dget_altitude

Attempts:

3 left

💡 Hint

Common Mistakes

Using calculate_altitude() which might not exist

Using read_altitude() which is not standard

The method get_altitude() converts pressure to altitude based on sensor data.

3fill in blank

hard

Fix the error in the code to initialize the barometer sensor correctly.

Drone Programming

barometer = BarometerSensor([1])

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

Aport1

Bsensor_port

Ci2c_bus

Dgpio_pin

Attempts:

3 left

💡 Hint

Common Mistakes

Using gpio_pin which is for digital pins

Using port1 or sensor_port which are not standard identifiers

The barometer sensor is connected via the I2C bus, so i2c_bus is the correct parameter.

4fill in blank

hard

Fill both blanks to create a set of altitudes for each sensor reading above 100 meters.

Drone Programming

altitudes = {reading[1]2 for reading in readings if reading [2] 100}

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

A**

B>

C<

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Using '+' instead of '**' for squaring

Using '<' instead of '>' in the condition

The code squares each reading (using **2) and filters readings greater than 100 meters.

5fill in blank

hard

Fill all three blanks to create a dictionary mapping sensor IDs to altitudes above 50 meters.

Drone Programming

altitude_map = [1]: [2] for id, [3] in sensor_data.items() if [2] > 50}

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

Aid

Baltitude

Ddata

Attempts:

3 left

💡 Hint

Common Mistakes

Using data as the loop variable instead of altitude

Mixing up keys and values in the dictionary comprehension

The dictionary maps id to altitude for each altitude item in sensor_data where altitude is above 50 meters.

Practice

1. What does a barometer measure to help a drone find its altitude?

easy

A. Battery level

B. Temperature

C. Wind speed

D. Air pressure

Solution

1. Step 1: Understand barometer function

   A barometer measures air pressure, which changes with altitude.

2. Step 2: Connect air pressure to altitude

   Lower air pressure means higher altitude, so drones use this to estimate height.

3. Final Answer:

   Air pressure -> Option D

4. Quick Check:

   Barometer = Air pressure [OK]

Hint: Barometer always measures air pressure, not temperature or speed [OK]

Common Mistakes:

• Confusing barometer with thermometer
• Thinking it measures wind speed
• Assuming it measures GPS signals

2. Which of the following is the correct way to read a barometer sensor value in drone code?

easy

A. altitude = barometer.readAltitude()

B. pressure = barometer.getTemperature()

C. pressure = barometer.readPressure()

D. altitude = barometer.getSpeed()

Solution

1. Step 1: Identify correct method for pressure reading

   The method readPressure() is used to get air pressure from the barometer.

2. Step 2: Check other options for correctness

   getTemperature() reads temperature, readAltitude() may not exist, and getSpeed() is unrelated.

3. Final Answer:

   pressure = barometer.readPressure() -> Option C

4. Quick Check:

   Read pressure with readPressure() [OK]

Hint: Pressure reading uses readPressure(), not temperature or speed [OK]

Common Mistakes:

• Using temperature method instead of pressure
• Assuming altitude is directly read
• Calling non-existent getSpeed() method

3. Given this code snippet, what will be printed?

pressure = 101325
altitude = 44330 * (1 - (pressure / 101325) ** 0.1903)
print(round(altitude))

medium

A. 0

B. 44330

C. 101325

D. 1903

Solution

1. Step 1: Understand the formula and input

   The pressure is 101325 Pa, which is sea level standard pressure.

2. Step 2: Calculate altitude

   Substitute pressure: (pressure / 101325) = 1, so (1) ** 0.1903 = 1, then 1 - 1 = 0, so altitude = 44330 * 0 = 0.

3. Final Answer:

   0 -> Option A

4. Quick Check:

   Sea level pressure gives altitude 0 [OK]

Hint: At sea level pressure, altitude formula returns zero [OK]

Common Mistakes:

• Misapplying exponent
• Ignoring that pressure equals standard pressure
• Confusing units

4. Find the error in this altitude calculation code:

pressure = barometer.readPressure()
altitude = 44330 * (1 - (pressure / 101325) ** 1.903)
print(altitude)

medium

A. Exponent should be 0.1903, not 1.903

B. Pressure should be divided by 100000, not 101325

C. Missing parentheses around pressure division

D. Altitude formula should multiply by pressure, not subtract

Solution

1. Step 1: Check the exponent value in formula

   The correct exponent in the barometric formula is approximately 0.1903, not 1.903.

2. Step 2: Understand impact of wrong exponent

   Using 1.903 will give incorrect altitude values, making the calculation invalid.

3. Final Answer:

   Exponent should be 0.1903, not 1.903 -> Option A

4. Quick Check:

   Exponent = 0.1903 for altitude formula [OK]

Hint: Check exponent carefully; 0.1903 is standard for altitude [OK]

Common Mistakes:

• Typing 1.903 instead of 0.1903
• Changing pressure divisor incorrectly
• Misplacing parentheses

5. You want to estimate altitude using a barometer when GPS is unavailable. Which approach correctly converts pressure to altitude in your drone program?

def pressure_to_altitude(pressure):
    sea_level_pressure = 101325
    altitude = 44330 * (1 - (pressure / sea_level_pressure) ** 0.1903)
    return round(altitude)

current_pressure = barometer.readPressure()
print(pressure_to_altitude(current_pressure))

hard

A. The sea level pressure should be updated dynamically inside the function

B. This code correctly converts pressure to altitude using the standard formula

C. The formula should use addition instead of subtraction inside parentheses

D. The function should return pressure, not altitude

Solution

1. Step 1: Analyze the formula used in the function

   The formula matches the standard barometric formula to convert pressure to altitude.

2. Step 2: Check the function usage and return value

   The function reads current pressure, applies formula, rounds result, and returns altitude correctly.

3. Final Answer:

   This code correctly converts pressure to altitude using the standard formula -> Option B

4. Quick Check:

   Standard formula used correctly [OK]

Hint: Use standard formula with subtraction and exponent 0.1903 [OK]

Common Mistakes:

• Changing formula signs incorrectly
• Not rounding altitude
• Returning wrong value