Case 15: High-Altitude Wind Turbine

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Introduction

Use the micro:bit V2 board's built-in light sensor to distinguish day and night — the wind turbine only starts when there is sufficient daylight (light value > 30). Once started, the rotational speed of the 360° building-block servo is controlled in real time by the sound level detected by the micro:bit V2's microphone — the louder the sound, the faster the rotation speed (0–100), simulating a wind turbine generating power by relying on airflow when there is sufficient light. When it is dim (light value ≤ 30), the servo automatically stops.

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Learning Objectives

1. Understand dual-condition judgment — both "sufficient light" and "wind (sound)" conditions must be met simultaneously to generate power.
2. Learn the combined use of light sensor and sound sensor — simulating real high-altitude wind turbine wind speed + light perception.
3. Explore high-altitude wind energy — at 300–500 meters altitude, wind speeds are 2–3× higher than at ground level, making it one of the most promising renewable energy sources.
4. Learn conditional nesting — first check light, then control speed based on sound.

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Required Materials

Item	Image	Quantity
micro:bit V2		1
Jacdac Expansion Board		1
Jacdac 10cm Connector Cable		2
Jacdac 25cm Connector Cable		1
Jacdac Light Sensor		1
Jacdac Servo Module		1
360° Building-Block Servo		1
USB Cable		1

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Sensor Principle

micro:bit V2 Built-in Light Sensor and Microphone

This case uses two types of sensors built into the micro:bit V2 board, requiring no external sensor modules:

Sensor	Measurement	Threshold in This Case	Description
micro:bit V2 Light Sensor	Ambient light intensity	> 30 (start generation)	Sufficient light → start servo, simulating wind turbine operation
micro:bit V2 Microphone	Sound level	0–255 (mapped to 0–100 speed)	Louder sound → faster servo speed, simulating wind speed

Note: This case uses a light sensor to simulate "daytime" judgment for teaching simplification purposes only. Real high-altitude wind turbines can operate around the clock.

Assembly Steps

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Model Principle

High-Altitude Wind Turbine — Capturing Stronger Winds

Traditional wind turbines are built on the ground or at sea, with tower heights typically not exceeding 160 meters. However, at altitudes of 300–500 meters, wind speeds are 2–3× higher than at ground level and more stable. High-Altitude Wind Energy (HAWE) is one of the hottest research areas in renewable energy in recent years.

Altitude	Typical Wind Speed	Wind Power Density
Ground (10 m)	~4–6 m/s	Baseline
Tower top (100–160 m)	~7–10 m/s	~3–5×
High altitude (300–500 m)	~10–15 m/s	~8–27×

Wind power is proportional to the cube of wind speed — double the wind speed, and power increases eightfold. This is why engineers go to great lengths to send wind turbines to high altitudes.

The 360° building-block servo drives the blades, simulating a high-altitude wind turbine continuously generating power in powerful airflow.

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Connection Diagram

As shown below, insert the micro:bit V2 board into the Jacdac expansion board, and use cables to connect the 360° building-block servo module and light sensor to the Jacdac expansion board's edge connector.

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Programming Software

Microsoft MakeCode

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MakeCode Programming

Step 1: Adding the Jacdac Extension

1. Go to Microsoft MakeCode and click "New Project".

   

2. Enter a project name in the pop-up window and click "Create".

   

3. Click "Extensions" in the code drawer.

   

4. In the pop-up interface, type "Jacdac" and click the search icon, then select the Jacdac software library as shown.

   

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Step 2: Connecting the Hardware

1. Use a USB cable to connect the micro:bit V2 board to the computer.

   Note: If this is the first time running a Jacdac program on the micro:bit V2, please pre-load a blank Jacdac program onto the board first. Otherwise, skip this step.

   

2. Connect the sensor. MakeCode will automatically detect and simulate it in the simulator area, where sensor status is displayed in real time.

   

3. Click "ADD BLOCKS" to add the sensor extension module.

   Note: When connecting a new sensor, repeat the "click 'ADD BLOCKS'" workflow once.

   

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Write the Program as Shown

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Reference Program Link

📎https://makecode.microbit.org/_8jiRxMVJ93v1

You can also download the program directly from the webpage below. Once downloaded, you can start running the program.

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Result

When there is sufficient light (light value > 30), speak loudly or clap toward the micro:bit V2 board, and the 360° building-block servo begins to rotate — the louder the sound, the faster the rotation (0–100), simulating a daytime wind turbine spinning with the wind. When it's quiet, the servo stops. After covering the LED matrix to simulate darkness or an overcast day (light value ≤ 30), no matter how loud the sound, the servo remains stationary — "insufficient light, no power generation."

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Think

1. This case uses sound to simulate wind speed. If you wanted to actually measure wind speed, what sensor would you need? (Hint: anemometer / wind cup)
2. Why do high-altitude wind turbines choose an altitude of 300–500 meters? Why not fly even higher? (Hint: aviation safety, tether cable weight)

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Program Logic

Trigger Condition	Action	Source
Light value > 30 (daytime) AND sound detected	360° building-block servo speed = sound value (0–255) → mapped (0–100); louder sound → faster rotation	micro:bit V2 Light Sensor + Microphone
Light value > 30 (daytime) AND complete silence	Servo stops (mapped value = 0)	micro:bit V2 Light Sensor + Microphone
Light value ≤ 30 (nighttime/dark)	Servo stops rotating	micro:bit V2 Light Sensor

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Knowledge Extension: High-Altitude Wind Energy — The Next Generation of Clean Energy

I. Why Send Wind Turbines to High Altitudes?

Ground-level wind is affected by terrain, buildings, and vegetation friction — it is slow and unstable. As altitude increases, surface friction decreases, and wind speed significantly increases. This phenomenon is called Wind Shear:

Altitude	Wind Speed Multiple (relative to 10 m)	Power Multiple
10 m (ground)	×1.0	×1
100 m (tower top)	×1.5–2.0	×3–8
300 m	×2.0–2.5	×8–16
500 m	×2.5–3.0	×16–27

II. High-Altitude Wind Energy Technology Approaches

Multiple companies and technology pathways worldwide are competing in the high-altitude wind energy space:

Technology Approach	Principle	Representative Company
Tethered kite	Large kites fly in "figure-8" patterns in the air, pulling a ground-based generator via tether cable	Kitekraft
Tethered drone	Multi-rotor drones carry small wind turbines aloft, transmitting power via cable	Altaeros (aerostat balloon + turbine)
High-altitude aerostat	Helium airship lifts a wind turbine to 300–600 m altitude	Altaeros BAT

It is estimated that the theoretical reserves of high-altitude wind energy far exceed those of ground-level wind energy. However, the technology is still in early stages — safely operating a tether system hundreds of meters long through thunderstorms, icing, and extreme winds is the greatest engineering challenge. Notably, real high-altitude wind turbines can operate around the clock (both day and night). This case's use of a light sensor to judge "sufficient light → generate power" is a simplified teaching design only.