L29 — Smart Home

🎯Learning Objectives

• Explain what IoT means and give three examples of smart home devices
• Describe how smart home devices communicate (Wi-Fi, Zigbee, voice assistants)
• List the benefits and risks of a smart home
• Control a virtual smart home in the browser using the Home Assistant demo

📖Theory

1. What Is a Smart Home?

A smart home is a house where everyday devices — lights, locks, heating, cameras — are connected to the internet and can be controlled remotely or automatically.

Examples you've probably seen or heard of:

• Smart light bulbs that you turn on with your phone or voice
• Smart thermostat that learns your schedule and adjusts temperature automatically
• Smart door lock that lets you in with a fingerprint or a code instead of a key
• Security camera that sends a notification when it detects motion
• Smart speaker (Alexa, Google Home) that answers questions and controls other devices

2. What Is IoT?

IoT stands for Internet of Things — the idea that ordinary physical objects ("things") can be connected to the internet and exchange data.

A light bulb isn't normally connected to the internet. A smart light bulb is — it can receive commands ("turn on"), report status ("I'm at 70% brightness"), and be part of automations.

The number of IoT devices worldwide in 2024 is over 15 billion — more than twice the number of people on Earth.

3. How Smart Home Devices Communicate

Smart home devices use different wireless technologies depending on their purpose:

Most smart home systems use a hub — a central box that speaks all these languages and connects to your home Wi-Fi. Your phone app talks to the hub; the hub talks to each device.

Popular hubs: Google Home, Amazon Alexa, Apple HomeKit, Home Assistant (open-source, free).

4. Voice Control

Smart speakers like Google Nest or Amazon Echo respond to voice commands:

• "Hey Google, turn off the lights in the bedroom."
• "Alexa, set the thermostat to 22 degrees."
• "Hey Siri, lock the front door."

The speaker sends your voice to the cloud, converts it to text, finds the command, and sends instructions back to the device — all in under 1 second.

5. Smart Home Automations

The most powerful feature of a smart home is automation — rules that run without you doing anything:

This is literally the algorithm from L24 written in a smart home app:

• Trigger = when the event happens
• Condition = if this is true
• Action = do this

6. Benefits and Risks

7. Home Assistant — A Free, Open Smart Home System

Home Assistant is a free, open-source smart home platform. It runs on a Raspberry Pi (a tiny $35 computer) at home and doesn't send your data to any company server.

You don't need to buy hardware today — there's a live demo you can explore in the browser right now.

Open: demo.home-assistant.io

No login needed. You'll see a real smart home dashboard with lights, temperature, media players, and a map.

💻Code Examples

Example A — What an automation looks like (YAML)

In Home Assistant, automations are written in a simple format called YAML. Here's a real example:

automation:
  - alias: "Turn off lights at night"
    trigger:
      - platform: time
        at: "23:00"
    action:
      - service: light.turn_off
        target:
          entity_id: light.living_room

Reading it in English: "At 23:00, turn off the living room light."

Even without knowing YAML, you can read it like a flowchart:

• Alias: name of the automation
• Trigger: when to run it (at 23:00)
• Action: what to do (turn off light)

Example B — A "Good morning" routine

automation:
  - alias: "Good morning routine"
    trigger:
      - platform: time
        at: "07:00"
    condition:
      - condition: time
        weekday: [mon, tue, wed, thu, fri]
    action:
      - service: light.turn_on
        data:
          brightness_pct: 50
        target:
          entity_id: light.bedroom

Trigger at 07:00 → Condition weekday only → Action: turn on bedroom light at 50%.

✏️Practice Tasks

⚠️Common Mistakes

Thinking "smart" always means "better"

A smart light bulb is worse than a regular one if the Wi-Fi goes down and you can't turn the lights on manually. Every smart device should have a backup way to use it.

Confusing IoT with AI

IoT = devices connected to the internet. AI = software that makes smart decisions. A smart thermostat that learns your schedule uses both. A smart plug you turn on with your phone is just IoT.

Leaving default passwords on devices

Many cheap cameras and routers ship with a default password like admin / admin. Change them immediately — otherwise anyone can access your home camera from the internet.

🎓Instructor Notes

⚡ How to run this lesson (~80 min)

• [5 min] Hook. Ask who has a smart device at home. Ask one student to explain how they control it.
• [15 min] Theory. Use real product photos. Focus on the communication table and the automation idea.
• [10 min] Demo: Home Assistant. Project demo.home-assistant.io. Click through lights, energy panel, open one automation.
• [30 min] Tasks 1 + 2 in class. Task 1 = exploration; Task 2 = design challenge (pairs optional).
• [15 min] Share designs. 3–4 groups present their $500 setup. Class votes on most practical.
• [5 min] Preview L30. Digital marketing — we'll create a poster/landing page for the app from L27.

💬 Discussion questions

• "Which single automation would save you the most time every day?"
• "If a company can see when you turn your lights on or off, what could they figure out about you?"
• "Should schools install smart cameras or sensors? What are the trade-offs?"