Perform a sexy light show with your Raspberry Pi and some LEDs!
You're going to need a Raspberry Pi (RPi) 3 Model B, a breadboard, 5 through-hole LEDs, and 5 through-hole ~270Ω resistors. The program is unlikely to meet performance requirements on older RPis due to high processing needs; although, it may still work on older models if you tweak some settings in constants.py.
The hardware setup for this program is very similar to that of rpi-volume-led. The readme for that project has all the instructions you'll need to set up one LED to your RPi. rpi-volume-led also comes with tests which make troubleshooting easy if anything goes wrong.
Once you're comfortable setting up one LED, set up five for this project. The default pins used are 12, 18, 22, 36, and 38; and the LEDs should be placed in that order.
In order for Python to use the RPi's GPIO pins, you need to run this program as root:
sudo ./start_rpi_led_lightshow.py
If you want to use different GPIO pins than the ones listed in the previous section you can specify exactly 5 pins using
sudo ./start_rpi_led_lightshow.py -p 1 2 3 4 5
where 1, 2, 3, 4, and 5 are example GPIO pin numbers.
If you're changing settings in constants.py and want another visualization of what's happening in the program, you can print the un-averaged duty cycles to the terminal using
sudo ./start_rpi_led_lightshow.py --show-duty-cycles
The core of the lightshow is based on frequency analysis (and the core of that is the Fast Fourier Transform), which is supplemented by a few other techniques to make the light show as tight as possible ("hit" thresholds, averaging).
There are 5 LEDs: The lowest frequency LED is designed to follow the beat by listening for sounds similar to a kick drum. The second lowest frequency LED is meant to capture a snare drum, but depending on the production of the song, might pick up something else; the criteria we followed for this LED is that it supported the lowest frequency LED as well as possible.
Most of the variation is meant to happen in the two lowest frequency LEDs. The next three LEDs capture overlapping regions of the midrange. They are not meant to track any specific instrument or sound but moreso light up with the general midrange intensity of the song.
Click the YouTube thumbnail below to find out!
