Raspberry Pi Camera setup - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Raspberry Pi camera capture code?

Consider this Python code snippet using the picamera library to capture an image. What will it print?

Raspberry Pi

import picamera
from time import sleep

with picamera.PiCamera() as camera:
    camera.resolution = (640, 480)
    camera.start_preview()
    sleep(2)
    camera.capture('/home/pi/image.jpg')
    print('Image captured at resolution:', camera.resolution)

A Image captured at resolution: (640, 480)

B Image captured at resolution: (1920, 1080)

C Error: PiCamera not found

D Image captured at resolution: (320, 240)

💡 Hint

Check the resolution set before capture.

The code sets the camera resolution to (640, 480) before capturing. The print statement outputs this resolution.

🧠 Conceptual

intermediate

Which command enables the Raspberry Pi camera interface?

To use the Raspberry Pi camera module, you must enable the camera interface. Which command correctly enables it?

A sudo systemctl start camera.service

B sudo apt-get install camera-enable

C sudo raspi-config and enable Camera under Interface Options

D sudo modprobe bcm2835-v4l2

💡 Hint

Think about the Raspberry Pi configuration tool.

The camera interface is enabled via sudo raspi-config under Interface Options > Camera.

🔧 Debug

advanced

Why does this Raspberry Pi camera capture code raise an error?

Look at this code snippet. It raises an error when run. What is the cause?

Raspberry Pi

import picamera

camera = picamera.PiCamera()
camera.capture('test.jpg')
camera.close()

A The camera needs to be started with start_preview() before capture()

B The capture() method requires a delay before calling

C The file path 'test.jpg' is invalid without full path

D The camera object must be used inside a with statement or closed properly

💡 Hint

Consider resource management and proper closing of the camera.

Not using a with statement or properly closing the camera can cause errors. Here, camera.close() is called, but if an exception occurs before, the camera may not close properly. Using with ensures proper cleanup.

📝 Syntax

advanced

Which option correctly sets the camera resolution and captures an image?

Choose the code snippet that correctly sets the resolution to 1280x720 and captures an image named 'photo.jpg'.

A

with picamera.PiCamera() as camera:
    camera.resolution = (1280, 720)
    camera.capture('photo.jpg')

B

with picamera.PiCamera() as camera:
    camera.set_resolution(1280, 720)
    camera.capture('photo.jpg')

C

camera = picamera.PiCamera()
camera.resolution = 1280, 720
camera.capture('photo.jpg')
camera.close()

D

with picamera.PiCamera() as camera:
    camera.resolution = [1280, 720]
    camera.capture('photo.jpg')

💡 Hint

Check the correct attribute name and data type for resolution.

The resolution attribute expects a tuple like (1280, 720). Option A uses this correctly. Option A uses a non-existent method. Option A misses closing the camera properly in a with block. Option A uses a list instead of a tuple, which is invalid.

🚀 Application

expert

How many images are saved after running this Raspberry Pi camera burst capture code?

This code captures 5 images in a burst with 1 second delay between each. How many image files will be saved?

Raspberry Pi

import picamera
from time import sleep

with picamera.PiCamera() as camera:
    camera.resolution = (640, 480)
    for i in range(5):
        camera.capture(f'/home/pi/image_{i}.jpg')
        sleep(1)

A 1

B 5

C 0

D 6

💡 Hint

Count how many times the capture method is called in the loop.

The loop runs 5 times, capturing and saving an image each time with a unique filename. So, 5 images are saved.