Part 5 · Smart Temperature¶
What you'll build
An automatic climate-control system that reads the air temperature, displays it on an LCD, and turns a fan on when things get too hot. The kind of system that keeps server rooms, greenhouses, and indoor public spaces comfortable without anyone touching a thermostat.
Smart-city pillar: 🌿 Comfort — Smart Environment & Climate Monitoring Components: Temperature & Humidity Sensor (DHT11), DC Motor (Fan), LCD Display Time: ~2 hours total
Why a smart city needs this¶
Cities are getting hotter — urban heat-island effects mean a downtown can be 5–10 °C warmer than the suburbs around it. Smart climate-monitoring networks of sensors feed:
- Public alerts during heatwaves
- Automated cooling in transit stations and shelters
- Energy-grid load forecasts (more cooling = more electricity demand)
- Long-term data on neighbourhood-level climate trends
Your project is one tiny node of that climate-monitoring network: read, display, react.
How the system thinks¶
┌─────────────────────────────────┐
│ Read DHT11 temperature & humidity│
└──────┬──────────────────────────┘
│
┌───▼──────────────────┐
│ Show on LCD: │
│ Line 1: Temp = 24 C │
│ Line 2: Hum = 55% │
└──────┬───────────────┘
│
┌──────▼──────────┐
│ Temp too hot? │── No ──→ Fan OFF
└──────┬──────────┘
│ Yes
▼
Fan ON
In IF/THEN logic:
- IF temperature is high (above your threshold) → THEN turn fan ON
- IF temperature is normal → THEN turn fan OFF
- Always: show live temperature and humidity on the LCD
What you'll learn (in this Part)¶
Work through each component lesson, then bring them together in the build:
- Temperature & Humidity (DHT11) — your environmental sensor
- DC Motor (Fan) — cools the space when triggered
- LCD Display — shows the live readings
- Build the Smart Temperature System — tie everything together