I just started learning how to play the guitar this past year and it's been a great hobby. Plus its a a great way to decompress and get CREATIVE! This semester, I started playing guitar for one of my clubs and we turn the lights off to project lyrics on the screen. I thought it would be fun to add lights to the experience when I play. Music is such a beautiful form of art and although I'm still learning the guitar (the music I make isn't the most beautiful YET), I think the lights are a cool way to mix two forms of art: visual and auditory.

What better way to feel like a rock star than flashing lights?!

Supplies

Guitar Strap
Feather Boa (or decoration of your choice)
Circuit Playground Bluefruit
LED Strip
Battery Pack and Batteries
Alligator clips
Needle and Thread or Safety Pins
Tape

Step 1: Set Up Sound Reactive Lights

Above are videos of how the lights react to different music. I mainly made this project to work with a guitar but I think it would really fit if you were playing with a whole band with drums and vocals too. This works best with live acoustic music - I discovered that some songs I played from Spotify actually have pretty consistent volume all throughout the song.

The main the feature of the Circuit Playground Bluefruit we'll be using is the mic.

I originally set up my sound using from adafruit_circuitplayground import cp and calling cp.sound_level to set the brightness as brightness = (cp.sound_level/(sound_max/100)/100). This pulsed the lights so that louder sounds, typically the beat, would show brighter lights. And each time the color would change through a list of Rainbow colors.

I then discovered some sources on Adafruit that worked with reacting to sound that I will link below:

Sound Reactive Drums

Sound Meter

From the Sound Meter, I really liked the effect of having the color change as a measure of sound and having a peak color. You can keep the effect where the pixels light up like a meter but this effect was not as noticeable on the guitar strap. Instead, I want all of my LED pixels to be on at the same time for the full effect and leave the pulsing to the brightness.

You can find the code for the Sound Meter through the link above. I tweaked this code using the previous code that I had written to make the colors and brightness pulse based on the magnitude of sound. I also created a threshold to be 150 for when the PEAK_COLOR would be shown (you can adjust the threshold accordingly).

You can also play around with what animation style to program the LED strips to do. Some inspiration I found but didn't end up using:

Comet Tail Animation

RaspberryPi Scroll Visualization

Another thing to note while changing the code is the input_ceiling. Make sure to adjust this value to whatever sound you will be using. Test to see how loud you can get! One thing I found was that the mic picked up music played from my computer versus my guitar differently. You'll have to test and test again.

Step 2: Attach Feather Boa to Guitar Strap

I removed the guitar strap from the guitar and lined the feather boa alongside it. My feather boa is longer than my guitar strap so I folded it in half to better fit my guitar strap. You can also cut your feather boa to the desired length. I matched the feather boa to the right side of the guitar strap and used safety pins to secure it into place. If you go the sewing route, this is where you would take a needle and thread and tack the feather boa down where you would use safety pins. I first pinned down the two ends and the middle then went back to fill in the gaps.

You can totally customize your guitar strap how you want. I like the feather boa because it diffuses the light and the feathers have really intricate texture. I also think they add a certain flare to the whole performance!

Step 3: Attach LED Strip

Once the feather boa is attached, you can add the LED strip. I did this by feeding the strip through my feather boa in the gaps between where I tacked the feather boa down. The feather boa is essentially the string that sews the LED strip to the guitar strap. I added more reinforcement with some sewing thread to tie the LED strip down but this isn't necessary if your boa is secure.

I clipped the battery pack to the front end of the guitar strap and used tape to further secure it. I then attached the CPB to the top of the battery pack in the front as well.

Step 4: Give It a Strum

Above are videos of what the finished product looks like and how it works!

Once you have everything set up, you can put the strap back on the guitar and test it out. You will need to tweak the threshold a little since the CPB is now closer to the guitar and that proximity affects the sound input. Add print statements to your code to help determine what to set the threshold. I set mine to 300.

Now you are all set to take your guitar strap to your next jam session! Whether it's in your parents' garage or on a big stage you are the star of the concert.