Album art bottle LEDs

I got a Pimoroni Wireless Plasma Kit and wanted to do something fun with it! I had the idea to create a custom palette of colors based on what I was listening to!

Album art is often iconic and I thought it'd be cool to get a subtle hint of the colors of my favorite album covers as their songs play!

I realized that last.fm shares album art over its API and as a long time member, that seemed like a great place to start.

By combining code for API access, dominant color extraction, NeoPixel updates and socket networking I was able to throw this together in an evening.

Materials

• A last.fm account to pull from w/ API key
• A 'server' (such as a Raspberry Pi Pico) to talk to the LEDs
  • I've used the Pimoroni Wireless Plasma Kit
• A 'client' computer which:
  • Plays music / can obtain the currently playing song (eg mpc/mpd)
  • Generate color palettes via API calls
  • [Optionally] detects BPM (via eg bpm from bpm-tools)

Workflow

I really wish the pico could do all of the image processing but jpeg decoding let alone kmeans is probably a tall order...so I arrived at this slightly hacky client/server architecture.

The client code (running on a 'real' computer) does most of the heavy lifting by:

• Checking last.fm for the most recently scrobbled track
• Downloading it's cover art
• Extract the NUM_COLORS most common colors
• Padding that out to NUM_LEDS and sending the udpdate to the server.

Here's what that looks like, in the client's terminal; note the track name, album art visualization and palette preview:

(There are now 4 palette extraction algorithms and all of them are previewed though only one is sent to the server!)

The server code, running on the pico, is resonsible for:

• Accepting "palette" updates (which are a list of NUM_LED RGB values)
• Managing the LED colors

Running the project

• Have a look at the constants at the top of the client / server and see if you wanna make any adjustments
• Install the libraries in requirements.txt on your client
• Use thonny or something like it to run the server code on the pi
  • It'll glow green when it's ready for a client connection
• Run the client code (once you add the API key and username) on a 'real' computer to send palettes to the server

Good Stuff

• Proud of janky palette transition logic; exciting when songs switch!
• Gentle animation is nice
• Because the pico has wifi, it can be anywhere in your home! On a high shelf, even. Wireless is cool :-)
• The updates are pretty slick
• Once a palette has been recieved it'll keep on displaying it until a new one is recieved.
• Pretty pleased by the threading code on the pico for handling animation and network updates :-)

BPM support

If you set a BPM_CMD you should be able to have the lights pulse at the BPM of the audio!

I use a shell script like this:

#!/bin/bash
BPMPATH=`which bpm`
FFMPEGPATH=`which ffmpeg`
BCPATH=`which bc`

BASE=/mnt/media/music/music
PATH=`mpc status --format "%file%" | head -n1`

FULLPATH=$BASE/$PATH

# convert to raw audio using ffmpeg + measure bpm!
# Thanks to Mark Hills for `bpm` and https://gist.github.com/brimston3/34dbb439442a723313b019b92931887b !
bpm=$($FFMPEGPATH -hide_banner -loglevel error -vn -i "$FULLPATH" -ar 44100 -ac 1 -f f32le pipe:1 | $BPMPATH)
#echo "BPM=$bpm"

# Calculate Delay
delay=$($BCPATH -l <<< 60.0/$bpm)
#echo "Delay=$delay"
echo $delay

Future Work

Here are a few ideas I have for future improvements...

Client:

• Automatically choose the best number of clusters?
• TUI interace:
  • q for quit
  • 1,2,3,4 etc for different color extraction methods?
• cache recent songs:
  • can't really cache checks with last.fm; move to a model where we search last.fm for the song on change?
• API retries?
  • more interesting fake patterns if missing a song!
• extract hues rather than brightnesses?

Server:

• It's possible having all the LEDs stuff into a bottle isn't given the best sense of the palette -- might look cool mounted on a wall or somewhere else!
  • (train) lantern?
  • Mount them along a wall or around a window frame?
• More interesting animation patterns?
• create multiple "endpoints" for various controls
  • changing animation speed?
  • explicitly set LEDs
  • test pattern?

Bugs to fix:

Traceback (most recent call last):
  File "/home/jesse/projects/album_art_bottle_LEDs/plasma_client.py", line 3
40, in <module>
    main()
  File "/home/jesse/projects/album_art_bottle_LEDs/plasma_client.py", line 3
21, in main
    colors = generate_palette(session, methods)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/jesse/projects/album_art_bottle_LEDs/plasma_client.py", line 2
45, in generate_palette
    payload = get_info_from_last_scrobble()
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/jesse/projects/album_art_bottle_LEDs/plasma_client.py", line 1
55, in get_info_from_last_scrobble
    last_track = response.json()['recenttracks']['track'][0]
                 ~~~~~~~