How to Make a Music Reactive Light
A simple LED strip project that reacts to bass from an audio signal and doubles as steady desktop lighting.
This build adds a reactive LED strip behind a monitor or desk. A TIP31 transistor drives the strip from the low-frequency part of an audio signal, and a three-way switch lets the light run in reactive or always-on mode.
Supplies
- TIP31 transistor
- LED strip
- 3.5 mm audio jack
- Prototype board
- Three-way switch, DC socket, DC connectors, wire, and hot glue
Step 1: Build the driver circuit
Solder the TIP31 circuit on prototype board. The audio input controls the transistor, and the transistor controls the LED strip brightness.
Step 2: Add the mode switch
Wire the switch so one mode lets the strip follow the bass and another mode keeps the strip glowing steadily. This makes the project useful even when no music is playing.
Step 3: Mount the LED strip
Measure the length needed behind the monitor, cut the strip at a valid cut mark, stick it in place, and solder the strip sections in parallel.
Step 4: Share the power source
A small power distributor can feed both the monitor and the LED circuit from the same supply. Keep the connections insulated and strain-relieved.
Step 5: Test with music
Connect the 3.5 mm jack to the computer audio output, play a bass-heavy track, and adjust the audio level until the LED strip responds cleanly.
Original project reference: DiYmon on Instructables.