Planet Arduino

Christmas light displays winking and flashing in sync to music are a surefire way to rack up views on YouTube and annoy your neighbours. Inspired by one such video, [Akshay James] set up his own display and catalogued the process in this handy tutorial to get you started on your own for the next holiday season.

[James], using the digital audio workstation Studio One, took the MIDI data for the song ‘Carol of the Bells’ and used that as the light controller data for the project’s Arduino brain. Studio One sends out the song’s MIDI data, handled via the Hairless MIDI to serial bridge, to the Arduino which in turn sets the corresponding bit to on or off. That gets passed along to three 74HC595 shift registers — and their three respective relay boards — which finally trigger the relay for the string of lights.

From there, it’s a matter of wiring up the Arduino shift register boards, relays, and connecting the lights. Oh, and be sure to mount a speaker outdoors so passers-by can enjoy the music:

Be sure to set up a secondary power source for the relays, as drawing the power from the Arduino is likely to cause big problems. If your preferred digital audio workstation doesn’t have a virtual MIDI instrument, [James] used loopMIDI for the desired effect. He has also provided the code he used to save you some trouble if you’re building this during an invariably hectic holiday season.

Of course, you could always plug your lights into an IoT power bar and have fun that way.