What You'll Need

Micro:bit V2 (built-in microphone & 5×5 LED matrix)
Battery pack + 3×AAA alkaline (or USB power)
Large leaf (~20 cm long with fine veins)
Plastic straw (15–20 cm to hold the leaf)
Copper wire (≈30 cm of Ø 1 mm, bendable)
Copper wire (≈30 cm of Ø 1 mm, bendable)
Double-sided tape or Velcro (to mount Micro:bit)

Safety First!

!Use the hot-glue gun only under adult supervision.
!Handle copper wire carefully—ends can be sharp.
!Secure small parts so they can’t be swallowed by little ones.
!Work on a stable surface; keep liquids & electronics separate.

Let's Make It! Step-by-Step Guide

Prepare the Leaf

Step 1 of 5

Trim the leaf’s stem to ~2 cm.
Glue its stem end into the top of your plastic straw.

The Science Behind It

Wind makes the leaf rustle and vibrate. Those vibrations create sound waves picked up by the Micro:bit’s microphone, which measures amplitude (0–255). We scale that value into 0–5 LED columns, visualizing sound level → wind intensity in real time.

Helpful Tips

Angle the straw so the leaf “whispers” directly into the mic hole.
If readings are too low, reduce the straw-mic distance to 1–2 cm.
Use fresh, stiff leaves (like poplar or sycamore) for best vibration.
Shield the Mic:bit from rain using a small plastic box or bag.

Try These Variations!

1Wireless Alerts: Send a radio message to another Micro:bit or phone when wind > threshold.
2I²C Display: Attach an OLED to show dB readings numerically.
3Data Logging: Stream readings over USB or Bluetooth to graph wind trends.
4Multi-Leaf Array: Mount 2–3 leaves on separate wires to compare gust direction.

Micro:bit Wind Meter