Email alerts on sensor thresholds in Raspberry Pi - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the module needed to send emails.

Raspberry Pi

import [1]

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

Arandom

Btime

Csmtplib

Dos

Attempts:

3 left

💡 Hint

Common Mistakes

Importing unrelated modules like random or time.

The smtplib module is used to send emails in Python.

2fill in blank

medium

Complete the code to check if the sensor value exceeds the threshold.

Raspberry Pi

if sensor_value [1] threshold:

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

A>

B<

C==

D<=

Attempts:

3 left

💡 Hint

Common Mistakes

Using less than or equal operators instead of greater than.

We want to send an alert when the sensor value is greater than the threshold.

3fill in blank

hard

Fix the error in the code to create an SMTP connection.

Raspberry Pi

server = smtplib.SMTP([1], 587)

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

A'smtp.gmail.com'

Bsmtp.gmail.com

C'localhost'

Dlocalhost

Attempts:

3 left

💡 Hint

Common Mistakes

Not putting quotes around the server address.

The SMTP server address must be a string, so it needs quotes.

4fill in blank

hard

Fill both blanks to log in to the SMTP server with email and password.

Raspberry Pi

server.login([1], [2])

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

A'[e-mail]'

B'your_password'

C'smtp.gmail.com'

D'[e-mail]'

Attempts:

3 left

💡 Hint

Common Mistakes

Using server address or recipient email instead of login credentials.

You must provide your email and password as strings to log in.

5fill in blank

hard

Fill all three blanks to send an email alert with subject and body.

Raspberry Pi

message = f"Subject: [1]\n\n[2]"
server.sendmail([3], '[e-mail]', message)

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

A"Sensor Alert!"

B"The sensor value exceeded the threshold."

C'[e-mail]'

D'your_password'

Attempts:

3 left

💡 Hint

Common Mistakes

Using password instead of sender email in sendmail.

The subject and body are strings, and the sender email is needed to send the mail.

Practice

1. What is the main purpose of sending email alerts when a sensor value crosses a threshold on a Raspberry Pi?

easy

A. To store sensor data permanently in a database

B. To notify the user immediately about important sensor events

C. To increase the sensor's measurement accuracy

D. To reset the sensor automatically

Solution

1. Step 1: Understand the role of email alerts

   Email alerts are used to inform users instantly when something important happens, like a sensor crossing a limit.

2. Step 2: Compare options with this purpose

   Only To notify the user immediately about important sensor events matches this purpose. Options B, C, and D describe unrelated tasks.

3. Final Answer:

   To notify the user immediately about important sensor events -> Option B

4. Quick Check:

   Email alerts = notify user instantly [OK]

Hint: Email alerts are for instant notifications, not data storage [OK]

Common Mistakes:

• Confusing alerts with data logging
• Thinking alerts improve sensor accuracy
• Assuming alerts reset hardware automatically

2. Which of the following Python code snippets correctly sends an email alert when a sensor value exceeds 50?

easy

A. if sensor_value > 50:
send_email_alert()

B. if sensor_value < 50
send_email_alert()

C. if sensor_value > 50
send_email_alert()

D. if sensor_value > 50:
send_email_alert

Solution

1. Step 1: Check Python if-statement syntax

   Python requires a colon after the if condition and indentation for the block.

2. Step 2: Validate each option

   if sensor_value > 50: send_email_alert() has correct syntax and logic. if sensor_value < 50 send_email_alert() misses colon and wrong condition. if sensor_value > 50 send_email_alert() misses colon and indentation. if sensor_value > 50: send_email_alert misses parentheses for function call.

3. Final Answer:

   if sensor_value > 50: send_email_alert() -> Option A

4. Quick Check:

   Correct if syntax + function call = if sensor_value > 50: send_email_alert() [OK]

Hint: Remember colon and indentation after if, and parentheses for function calls [OK]

Common Mistakes:

• Missing colon after if condition
• Forgetting parentheses when calling functions
• Incorrect indentation causing syntax errors

3. Given the code below, what will be printed if sensor_value = 75?

def check_sensor(value):
    if value > 70:
        print("Alert: High sensor value!")
    else:
        print("Sensor value normal.")

check_sensor(sensor_value)

medium

A. Alert: High sensor value!

B. No output

C. Sensor value normal.

D. SyntaxError

Solution

1. Step 1: Analyze the condition with sensor_value = 75

   Since 75 > 70, the if condition is true.

2. Step 2: Determine which print statement runs

   The code prints "Alert: High sensor value!" because the if condition is met.

3. Final Answer:

   Alert: High sensor value! -> Option A

4. Quick Check:

   75 > 70 triggers alert print [OK]

Hint: Check if condition true or false to find printed message [OK]

Common Mistakes:

• Confusing else output with if output
• Assuming no output if condition true
• Thinking code has syntax errors

4. The following code is intended to send an email alert if the sensor value is above 60, but it does not work. What is the error?

sensor_value = 65
if sensor_value > 60
    send_email_alert()

medium

A. send_email_alert() is not defined

B. Indentation is incorrect

C. sensor_value should be a string

D. Missing colon after the if condition

Solution

1. Step 1: Check syntax of the if statement

   The if statement is missing a colon at the end of the condition line.

2. Step 2: Identify the cause of failure

   Without the colon, Python raises a syntax error and the code won't run.

3. Final Answer:

   Missing colon after the if condition -> Option D

4. Quick Check:

   if statement requires colon [:] [OK]

Hint: Always put a colon after if conditions in Python [OK]

Common Mistakes:

• Forgetting colon after if condition
• Assuming function is undefined without checking syntax first
• Thinking sensor_value must be string

5. You want to send an email alert only once when the sensor value crosses above 80, not repeatedly while it stays above 80. Which approach is best to implement this on a Raspberry Pi?

hard

A. Restart the Raspberry Pi after each alert to reset the sensor

B. Send an email every time the sensor value is checked and above 80

C. Use a flag variable to track if alert was already sent and reset it when value goes below 80

D. Ignore sensor values below 80 and send emails continuously

Solution

1. Step 1: Understand the problem of repeated alerts

   Sending emails repeatedly while the value stays high can spam the user.

2. Step 2: Use a flag to send alert only once

   A flag variable remembers if alert was sent; reset it when value drops below threshold to allow future alerts.

3. Final Answer:

   Use a flag variable to track if alert was already sent and reset it when value goes below 80 -> Option C

4. Quick Check:

   Flag variable prevents repeated alerts [OK]

Hint: Track alert state with a flag to avoid repeated emails [OK]

Common Mistakes:

• Sending emails every check causes spam
• Restarting device is inefficient and unnecessary
• Ignoring values below threshold misses reset opportunity