Email alerts on sensor thresholds in Raspberry Pi - Step-by-Step Execution

Concept Flow - Email alerts on sensor thresholds

Start Program

↓

Read Sensor Value

↓

Check if Value > Threshold?

No→Wait & Repeat

Yes↓

Send Email Alert

↓

Wait & Repeat

The program reads a sensor value, checks if it passes a set limit, sends an email if it does, then waits before checking again.

Execution Sample

Raspberry Pi

import smtplib
sensor_value = 75
threshold = 70
if sensor_value > threshold:
    send_email_alert()

This code checks if the sensor value is above the threshold and sends an email alert if true.

Execution Table

Step	Action	Sensor Value	Threshold	Condition (Value > Threshold)	Email Sent
1	Read sensor value	75	70	75 > 70 = True	No
2	Check condition	75	70	True	No
3	Send email alert	75	70	True	Yes
4	Wait before next read	75	70	True	Yes
5	Read sensor value again	65	70	65 > 70 = False	No
6	Check condition	65	70	False	No
7	No email sent, wait	65	70	False	No

💡 Program runs continuously; stops only if manually terminated.

Variable Tracker

Variable	Start	After Step 1	After Step 5	Final
sensor_value	None	75	65	65
threshold	70	70	70	70
email_sent	False	False	False	False

Key Moments - 2 Insights

Why does the program send an email only when the sensor value is above the threshold?

Because the condition 'sensor_value > threshold' must be True to trigger sending an email, as shown in execution_table rows 2 and 3.

What happens when the sensor value is below the threshold?

No email is sent and the program waits to read the sensor again, as seen in execution_table rows 5 to 7.

Visual Quiz - 3 Questions

Look at the execution table, at which step is the email alert sent?

A Step 2

B Step 3

C Step 5

D Step 7

💡 Hint

Check the 'Email Sent' column in the execution_table for when it changes to 'Yes'.

At which step does the sensor value fail to exceed the threshold?

A Step 1

B Step 3

C Step 5

D Step 2

💡 Hint

Look at the 'Condition (Value > Threshold)' column for 'False' value.

If the threshold was set to 80, what would happen at step 1?

A No email sent, condition false

B Email would be sent

C Program would crash

D Sensor value would change

💡 Hint

Compare sensor_value 75 with new threshold 80 in the condition column.

Concept Snapshot

Read sensor value continuously
Check if value exceeds threshold
If yes, send email alert
Wait before next reading
Repeat forever

Full Transcript

This program reads a sensor value on a Raspberry Pi and compares it to a set threshold. If the sensor value is higher than the threshold, it sends an email alert. Otherwise, it waits and reads the sensor again. This cycle repeats continuously to monitor sensor data and notify when limits are exceeded.