Quick Answer
- IoT (Internet of Things): Devices that collect data and send it to the internet.
Example: A fitness tracker sending steps to your phone.
- CPS (Cyber-Physical Systems): Devices that sense, think, and act on their own.
Example: A self-driving car braking to avoid a crash.

IoT: The Reporter

What it does: Collects data (like temperature or location) and sends it to the cloud or your phone.

Examples:

  • Smart thermostat texting you the room temperature.
  • Soil sensor emailing you when plants need water.
  • GPS tracker showing your pet’s location.

How it works:
Sensor → Internet → Cloud → Your Device
"Hey, it’s 72°F in here!"

CPS: The Smart Robot

What it does: Senses, processes, and acts instantly without needing the internet.

Examples:

  • Insulin pump delivering medicine when blood sugar drops.
  • Car braking automatically to avoid a collision.
  • Factory robot adjusting its movements in real-time.

How it works:
Sense → Think → Act → Repeat
"Obstacle ahead → Calculate risk → Brake now!"

Key Differences

  1. Where’s the Brain?
    • IoT: Brain in the cloud (needs internet to process data).
    • CPS: Brain in the device (thinks locally).
  2. Speed:
    • IoT: Can handle delays (seconds or minutes).
    • CPS: Must act instantly (milliseconds matter).
  3. No Internet?
    • IoT: Stops or becomes dumb.
    • CPS: Keeps working independently.

ESP32 Projects

IoT Example: Smart Plant Monitor
- What: Checks soil moisture and emails you if it’s dry.
- Why IoT: Needs internet to send alerts.
- Delay OK? Yes, plants can wait a few minutes.

void checkSoil() {
  if (soilDry) {
    sendEmail("Water your plants!"); // Can wait
  }
  delay(300000); // Wait 5 min
}

CPS Example: Auto-Balancing Robot
- What: Uses motors to stay upright.
- Why CPS: Must react instantly to avoid falling.
- Delay OK? No, delays cause crashes.

void balanceRobot() {
  readSensors();    // Check tilt
  calculateAdjustment(); // Think
  adjustMotors();   // Act now!
  // No delays!
}

Everyday Analogies

IoT is like:

  • A weather app telling you it’s raining.
  • A friend texting you updates.

CPS is like:

  • Your hand pulling back from a hot stove.
  • A chef adjusting a recipe while cooking.

Which to Use?

Pick IoT for:

  • Remote monitoring (e.g., checking home temp from work).
  • Non-urgent alerts (e.g., plant watering reminders).
  • Reliable internet access.

Pick CPS for:

  • Instant action (e.g., car braking).
  • Critical safety (e.g., medical devices).
  • Unreliable or no internet.

Real-World Examples

  • Smart Home:
    • IoT: Lights you control via an app.
    • CPS: Motion lights that turn on automatically.
  • Car:
    • IoT: App showing your car’s location.
    • CPS: Auto-braking system.
  • Health:
    • IoT: Smartwatch tracking sleep.
    • CPS: Pacemaker regulating heartbeats.

The Bottom Line

IoT: Connects and reports data ("Here’s what’s happening").
Great for: Monitoring, alerts.

CPS: Thinks and acts locally ("I’ll handle it").
Great for: Automation, safety.

They Team Up!
Many systems use both:
- A smart thermostat (CPS) adjusts temperature automatically and (IoT) sends energy reports to your phone.

Your Next Project

  • Weather station? → IoT (sends data to your phone).
  • Self-driving toy car? → CPS (needs instant decisions).
  • Auto-watering garden? → Both (senses, acts, and reports).

IoT informs you. CPS takes action.