30. Case 26: The Volume Indicator#

30.1. Introduction#

This is a sound warning device. As we all know, noise pollution seriously affects our lives. If we are exposed to a certain decibel noise for a long time, our physical and mental state will also be harmed. Thus, we can make a noise detection device. Different decibel values light up different colors of lights to remind people to keep quiet.


30.2. Quick Start#

Materials Required#

Nezha expansion board × 1

micro:bit V2 × 1

Rainbow LED ring × 1

Bricks × n

Tips: You may need to purchase Nezha Inventor’s Kit and Purchase Interactive coding accessories pack here. if you want all the above components.

Connection Diagram#

Inset the micro:bit, and connect the rainbow LED ring to IIC port on Nezha expansion board.


Assembly Video#

Video link: https://youtu.be/4tFv6rWx8uM

Assembly Steps#






30.3. MakeCode Programming#

Step 1#

Click “Advanced” in the MakeCode drawer to see more choices.


We need to add a package for programming. Click “Extensions” in the bottom of the drawer and search with “nezha” to download it.


Note: If you met a tip indicating the codebase might be deleted due to incompatibility, you may continue as the tips say or create a new project in the menu.

Step 2#

Programme as the pictures indicate#



Link: https://makecode.microbit.org/_5cCW2APhK263

You may download it directly below:


After powering on, the rainbow LED ring lights up in different colors reflecting with the ambient sound level.