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Smart Sensor Monitoring System using AWS IoT Core ​

Topics: IoT, AWS IoT Core, MQTT, CloudWatch, Event-Driven Architecture

Overview ​

This lab demonstrates cloud-based IoT data ingestion and processing using AWS IoT Core. A simulated IoT device sends sensor data (temperature and humidity) in JSON format to the AWS cloud. The data is received by AWS IoT Core, processed automatically through rules, and logged using CloudWatch for monitoring and verification. This exercise shows how real-time device data can be handled without managing servers, highlighting IoT, cloud computing, and event-driven architecture principles.

Key Concepts ​

ConceptDescription
AWS IoT CoreManaged cloud service that acts as the central message broker for IoT devices
IoT ThingVirtual representation of a physical IoT device in AWS
Device CertificateDigital certificate that provides secure identity for IoT devices
IoT PolicyDocument that defines permissions for IoT devices to connect and communicate
MQTT ProtocolLightweight messaging protocol used for IoT device communication
IoT RulesSQL-based rules that process incoming IoT data and trigger actions
Event-Driven ArchitectureSystem design where actions are triggered by events (data arrival)

Prerequisites ​

  • Active AWS account with billing enabled
  • IAM permissions for IoT Core, CloudWatch, and related services
  • Basic knowledge of JSON data format
  • Understanding of IoT concepts (optional but helpful)

Architecture Overview ​

Click to expand Architecture Diagram

Phase A: Create IoT Thing (Device) ​

  1. Go to AWS Console → IoT Core
  2. Navigate to Manage → Things
  3. Click Create things
  4. Choose Create single thing
  5. Give a name (example: TempSensor01)
  6. Skip advanced settings
  7. Click Create

This represents a sensor device (even though no real hardware is used).

Phase B: Create and Configure Device Certificate ​

  1. Choose Auto-generate certificate
  2. Activate the certificate
  3. Download:
    • Device certificate
    • Private key
    • Root CA
  4. Attach the certificate to the Thing

Certificate = identity of the device

Phase C: Create and Attach IoT Policy ​

  1. Go to Secure → Policies
  2. Create a new policy
  3. Allow:
    • Connect
    • Publish
    • Subscribe
    • Receive
  4. Use * (for lab simplicity)
  5. Attach the policy to the certificate

Policy = permission for device to talk to AWS

Phase D: Test Device Messages (No Hardware) ​

Go to Test → MQTT test client

Subscribe to a topic: sensor/temperature

Publish a message:

json
{
  "deviceId": "TempSensor01",
  "temperature": 32,
  "humidity": 65
}

Verify message appears instantly. IoT data successfully reached the cloud.

Phase E: Create a Rule (Automation) ​

  1. Go to Act → Rules
  2. Create a rule
  3. Rule query example: SELECT * FROM 'sensor/temperature'
  4. Choose action: Send to CloudWatch Logs (or Lambda/DynamoDB if required)

Rule = "when data arrives, do something"

Phase F: Verify Output ​

  1. Open CloudWatch → Logs
  2. Check log group created by IoT Rule
  3. Confirm sensor data entries

Automatic processing confirmed. Sensor data is sent to AWS IoT Core, where rules automatically process and store the data without using any server.

Validation ​

Validation
  • IoT Thing Created: Verify TempSensor01 appears in Things registry
  • Certificate Attached: Check certificate is active and attached to the thing
  • Policy Attached: Confirm policy allows required permissions
  • MQTT Test: Message published and received successfully
  • Rule Created: IoT rule exists with correct SQL query
  • CloudWatch Logs: Sensor data entries visible in log group

Cost Considerations ​

Cost Considerations
  • AWS IoT Core: Pay per message ($1 per million messages) + connection time
  • CloudWatch Logs: $0.50 per GB ingested
  • Free Tier: 250,000 messages/month, 5GB logs free
  • Estimated Cost: <$1 for this lab

Cleanup ​

Cleanup
  1. Delete IoT Rule
  2. Detach and deactivate certificate
  3. Delete IoT Policy
  4. Delete IoT Thing
  5. Delete CloudWatch log group

Result ​

Successfully implemented a serverless IoT data pipeline using AWS IoT Core. Demonstrated event-driven architecture where sensor data is automatically processed and logged without managing any servers. The system can scale to handle millions of devices and messages.

Viva Questions ​

  1. What is the role of AWS IoT Core in IoT applications?
  2. Why are certificates and policies important for IoT device security?
  3. How do IoT Rules enable event-driven processing?
  4. What are the benefits of using MQTT protocol for IoT?