The Arp Index

The Arp Index

Check stocks on norns (and make music).

video thumb
Video on Instagram

Listen to the sound of stocks falling, invest to push up the last note of your arpeggiator, do money things on norns.


Internet connection
Molly the Poly engine

MIDI note input optional
MIDI output optional


E1 : Company
E2 : Time span
E3 : Steps
K2 : Play/Stop
K1+K2 : Reset clock
K3 : Refresh

Use a MIDI controller to play and transpose multiple sequences at once.
Check params for scale, timing and synth options.


The Arp Index v1.0.1


it’s like you knew how often i joke that if norns could handle my portfolio, it’d be perfect!


whaaaat. this is so cool.

I just conceptually HAVE to use it on one of the tracks I’m working on. Using the fucking datas of their fucked up obsessions to make something useful out of it, that is : something that is of absolutely no use to them, it’s just a nice thought.


This looks wonderful! You continue to inspire :slight_smile:

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Shit, this new norns user/current finance major is mind blown by this right now :slightly_smiling_face::slightly_smiling_face:


Now THIS is really using the full scope of the Norns capabilities in an interesting direction! Referencing real world structures and numbers for musical output is a sweet sweet idea.


Hmm. Can’t seem to get any companies downloaded. Internet is up and running. Restarted after install. Maiden repl says:

|Error proessing companies|[]|
|Got companies|0|

Any ideas?

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Capitalism meets tech meets synthesizers? I’m in.

This is such a wonderfully novel concept, and it could actually inspire some interesting melodies for when I’m feeling undecided but don’t want to just play a random arpeggiator or up/down on a favorite chord.

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Good question, it seems the API is returning no results today - I’ll ask about it.


Sounds like it was something to do with the markets being closed for the US bank holiday :chart_with_downwards_trend:

Should be working again now everyone is back buying & selling :chart_with_upwards_trend:


Here’s a video showing a MIDI keyboard controlling the generated pattern and MIDI output (to CV) driving an external synth. The Arp Index plays nicely with others. :two_men_holding_hands:


This is super cool. 20 step 1 day pattern for Boeing is quite the descending line post 737 MAX + Starliner + firing CEO.

I see you have an API key for the stock data in the source code, which is fine but might break the script in the future. Is it possible to use import system env vars from the we user into Norns Lua? My python is much more strong today but something like putting IEXAPIS_TOKEN in .bashrc and then

import os
API_KEY = os.environ['IEXAPIS_TOKEN']
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Has anyone come across “error: init” when trying to run this? I’ve installed it via maiden. I get the same error from molly the poly

@voidstate Is there some console output in maiden?

@lazzarello not sure I really follow your suggestion here – if it’s about getting the API key out of the main script then why not just a lua file?

No it installs fine, when I run it on norns I get the initial screen ok then it kicks me back to the main menu with “error init” where the app name usually displays.

I was wondering about output when running the script?

lua version

API_KEY = os.getenv('IEXAPIS_TOKEN')
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I ran it in maiden and downloaded it to norns from there and now it works. Resolved!

@zebra lol, thanks. that makes a lot of sense.

@markeats just a different place to put it. It was a reflex from working with web APIs a lot. It could go anywhere really. It’s nbd.