Barometer for altitude in Drone Programming - Mini Project: Build & Apply

Barometer for Altitude

📖 Scenario: You are programming a drone that uses a barometer sensor to measure altitude. The barometer gives pressure readings, and you want to convert these readings into altitude values to help the drone fly safely.

🎯 Goal: Build a simple program that stores pressure readings, sets a baseline pressure, calculates altitude from each reading using a formula, and then prints the altitude values.

📋 What You'll Learn

Create a list called pressure_readings with exact pressure values

Create a variable called baseline_pressure with a specific value

Use a list comprehension to calculate altitude values from pressure readings

Print the list of altitude values

💡 Why This Matters

🌍 Real World

Drones use barometer sensors to measure altitude for safe flying and navigation.

💼 Career

Understanding sensor data processing and simple formulas is important for drone programming and robotics jobs.

1

Create pressure readings list

Create a list called pressure_readings with these exact values: 1013.25, 1000.00, 990.00, 980.00, 970.00

Drone Programming

# Create the list pressure_readings with the given values
# Your code here

Hint

Use square brackets [] to create a list and separate values with commas.

2

Set baseline pressure

Create a variable called baseline_pressure and set it to 1013.25 (standard sea level pressure in hPa).

Drone Programming

pressure_readings = [1013.25, 1000.00, 990.00, 980.00, 970.00]
# Create baseline_pressure variable with value 1013.25
# Your code here

Hint

Just assign the number 1013.25 to the variable baseline_pressure.

3

Calculate altitude from pressure

Use a list comprehension to create a list called altitudes. Calculate altitude for each pressure reading using the formula: altitude = 44330 * (1 - (pressure / baseline_pressure) ** 0.1903). Use pressure as the variable inside the comprehension.

Drone Programming

pressure_readings = [1013.25, 1000.00, 990.00, 980.00, 970.00]
baseline_pressure = 1013.25
# Create altitudes list using list comprehension and the given formula
# Your code here

Hint

Use the formula exactly and write a list comprehension with for pressure in pressure_readings.

4

Print altitude values

Write a print statement to display the altitudes list.

Drone Programming

pressure_readings = [1013.25, 1000.00, 990.00, 980.00, 970.00]
baseline_pressure = 1013.25
altitudes = [44330 * (1 - (pressure / baseline_pressure) ** 0.1903) for pressure in pressure_readings]
# Print the altitudes list
# Your code here

Hint

Just print the variable altitudes to see the list of altitude values.

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