After realizing that asking his kids to keep the noise down was meaningless without some sort of standard, maker Jeremy S. Cook decided to construct the “Hello Light.”
This cylindrical device measures sound with an electret microphone and an Arduino Nano, then commands a set of RGBW lights to progressively light up depending on the noise level.
In the end, the Hello Light eventually ended up as more of a game to see who could trigger the flashing volume limit warning—not particularly effective for its intended purpose. It does, however, make a fun interactive decoration, and also features a random lighting mode, and a slowly blinking white light setting.
Code for the project is available on GitHub, and the build process can be seen in the clip below.