Why serial communication connects to external devices in Raspberry Pi - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to open a serial connection on Raspberry Pi.

Raspberry Pi

import serial
ser = serial.Serial([1], 9600)

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

A'/dev/ttyS0'

B'/dev/ttyUSB0'

C'COM1'

D'/dev/null'

Attempts:

3 left

💡 Hint

Common Mistakes

Using Windows device names like 'COM1'.

Using non-existent device files.

On Raspberry Pi, serial devices are usually accessed via /dev/ttyS0.

2fill in blank

medium

Complete the code to send data over serial to an external device.

Raspberry Pi

ser.write([1])

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

Ab'Hello'

BHello

C'Hello'

Dbytearray('Hello')

Attempts:

3 left

💡 Hint

Common Mistakes

Sending a string without converting to bytes.

Using a plain string without prefix.

Data sent over serial must be bytes, so prefix the string with b.

3fill in blank

hard

Fix the error in reading data from the serial port.

Raspberry Pi

data = ser.read([1])

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

Aser.in_waiting

BNone

C10

D'10'

Attempts:

3 left

💡 Hint

Common Mistakes

Passing a string instead of an integer.

Passing None or invalid types.

The read() method expects an integer number of bytes to read.

4fill in blank

hard

Fill both blanks to create a dictionary of device names and their baud rates.

Raspberry Pi

devices = { [1]: 9600, [2]: 115200 }

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

A'sensor'

B'actuator'

C'controller'

D'display'

Attempts:

3 left

💡 Hint

Common Mistakes

Using numbers as keys.

Using the same device name twice.

We use device names as keys and common baud rates as values.

5fill in blank

hard

Fill all three blanks to filter devices with baud rate above 9600.

Raspberry Pi

fast_devices = { [1]: [2] for [3], rate in devices.items() if rate > 9600 }

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

Adevice

Brate

Cdevices

Dname

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong variable names.

Mixing up keys and values.

We iterate over devices.items() using name and rate, then filter by rate.