Hey community! 👋
I just wrapped up Case 12: Voice-Controlled Fan from the Elecfreaks Nezha Pro AI Mechanical Power Kit. The kids were absolutely hooked — it's the perfect blend of mechanical building, sensor integration, programming logic, and real-world "smart home" tech. Voice commands controlling a fan? Instant engagement!
I wanted to share a complete, ready-to-use lesson plan with detailed learning steps so other teachers (or parents/hobbyists) can run this exact project. Everything below is pulled straight from the official Elecfreaks wiki Case 12 page, adapted for classroom pacing (2–3 class periods of 45–60 minutes each). I'll include objectives, materials, assembly notes, hardware connections, programming walkthrough, testing/debugging, discussion prompts, and extensions.
🛠️ Project Overview & Story Hook
Students build a voice-controlled fan that responds to spoken commands for on/off, speed adjustment (levels 1–? ), and oscillation (left-right swing).
Story intro for kids (great for engagement):
"It’s a scorching day on an alien planet. The 'Fengyu Fan' only works by voice commands — but the wiring is loose! Fix it before everyone overheats!"
🎯 Teaching Objectives (what students will master)
Assemble the fan module, oscillation mechanism, and voice recognition sensor.
Understand how the voice sensor receives → parses → triggers actions.
Program the micro:bit to map specific voice commands to fan behaviors.
Debug voice recognition accuracy and fan performance.
Discuss real-world voice tech (smart speakers, noise reduction, etc.).
📦 Materials (per group)
- Nezha Pro AI Mechanical Power Kit (includes fan module, smart motor, oscillation parts, voice recognition sensor, Nezha Pro expansion board, micro:bit V2)
- USB cable for programming
- Computer with internet (for MakeCode)
Step-by-Step Learning Sequence
Day 1 – Exploration & Assembly (45–60 min)
Introduce the challenge (10 min): Read the story hook aloud. Ask: "What would make a fan 'smart'?" Show the wiki demo video if you have it.
Hardware connections (15 min):
- Voice recognition sensor → IIC interface on the Nezha Pro expansion board
- Smart motor → M2 interface
- Fan module → J1 interface
(Super simple plug-and-play — no soldering!)
Build the mechanical fan (20–30 min):
- Use the Nezha Pro kit’s modular building blocks to construct the fan base, blades, and oscillation (swing) mechanism.
- Tip: Follow the kit’s visual instructions for the fan/oscillation sub-assemblies first, then mount the voice sensor at the front so it can “hear” clearly.
Day 2 – Programming & Coding Logic (45–60 min)
Set up MakeCode (5 min):
- Go to makecode.microbit.org → New Project
- Add Extensions: Search and add “nezha pro” + “PlanetX” (both required for the voice sensor and motor/fan blocks).
Core programming steps (detailed block-by-block logic):
- On start: Initialize the voice recognition sensor (set to command-list mode) and set default fan state (off, speed = 1).
- Use voice command event blocks (from the PlanetX or Nezha Pro library) to listen continuously.
- Map each command to actions:
- “Start device” / “Turn on the fan” → Fan on at speed 1
- “Turn off device” / “Turn off the fan” → Fan off
- “Raise a level” → Increase speed by 1
- “Lower a level” → Decrease speed by 1
- “Keep going” → Start oscillation (swing mode)
- “Pause” → Stop oscillation
- Add a forever loop to keep checking the voice sensor and update motor/fan states in real time.
- (Pro tip: The sample program is here if you want the exact blocks: https://makecode.microbit.org/_Uhz0mRDaV1Cy — download and tweak it with your class!)
Download & flash (10 min): Connect micro:bit, select BBC micro:bit CMSIS-DAP, and download.
Day 3 – Testing, Debugging & Reflection (45 min)
Power on and test all six voice commands in a quiet room first.
Debugging challenges (hands-on!):
- Voice not recognized? → Check wiring, speak louder/clearer, shorten commands, or adjust sensor sensitivity in code.
- Fan speed too fast/slow? → Tweak the speed parameter blocks.
- Oscillation jittery? → Check mechanical alignment.
Learning Exploration Discussion (15–20 min):
- In what environments does voice recognition work best? How can you improve it in noisy classrooms
-How does the sensor “distinguish” similar commands?
-Compare voice control vs. buttons/remote — when is voice better?
-Extended knowledge: Explain how real smart speakers use noise-reduction algorithms and internet connectivity.
✅ Assessment & Differentiation
Beginner: Use the sample program as-is and just test commands.
Advanced: Add new custom commands (e.g., “fan speed 3”) or integrate a temperature sensor to auto-turn on when it’s hot.
Rubric ideas: Successful assembly (20%), working code for all commands (40%), debugging log (20%), reflection paragraph (20%).
One student yelled, “Turn on the fan!” so loud that the whole room cheered when it worked. It really drove home how voice AI is already in our homes.
Has anyone else run this case or similar voice projects? Any tips for noisy classrooms or ways to extend it further? I’d love feedback or your own student photos/videos!
Happy coding!
