picoTracker

picoTracker is a project that aims to provide a low cost open source and DIY hardware music tracker platform. It's firmware is essentially a modified version of LittleGPTracker (a.k.a piggy tracker) and keeps 90%+ of it's functionality, but I made some custom modifications, both functional and aesthetic and it might diverge more in the future. It implements a user interface similar to the refined track-by-joypad software littlesounddj. picoTracker currently supports 8 monophonic 8Bit/16Bit/44.1Khz stereo channels as well as 16 channel midi output.

Features

• 8 song channels
• 128 chains
• 128 phrases
• 32 tables
• 16 Sample instruments
• 16 MIDI instruments
• 1MB sample memory
• 8 or 16bit samples up to 44.1kHz, mono or stereo
• 16bit/44.1kHz/Stereo audio output

Limitations

• Will probably struggle with 8 song channels playing at the same time in most cases. I modified the source to parametrically reduce the total songs, but didn't want to make the decision of supporting only 6 songs or so just yet. There is still room for improvement by either multithreading or increasing CPU frequency.
• Cannot load LGPT projects (thou I wrote an ugly script to convert projects).
• Samples are played copied to flash upon load and played from there. Since flash has to be shared with program code, only 1MB is available for it when using the Raspberry Pi Pico, or up to 15MB when using other boards or custom hardware (i.e: the PicoTracker official hardware).
• Instrument count is also pretty low due to memory constraints. 16 Sample and 16 MIDI instruments.
• Sample instrument feedback feature has been removed due to memory constraints.
• Sample fonts support has been removed to save some memory.

Known issues

• Loading a project will leak memory. Current workaround is to do a full system reset upon project exit (done automatically).

TODO/Improvements/Wishlist

• [ ] Fix memory leak issues and modernize code
• [ ] Add new synth instruments (C64 SID WIP)
• [ ] Improve SDIO performance and explore further playing samples from SD
• [ ] Further memory savings and bring back some features/instruments
• [ ] Improve performance/make instrument rendering multithreading
• [ ] USB mass storage for writing samples into SD
• [ ] MIDI In
• [ ] USB MIDI

BUILD

Head over to the Picotracker Portable Build Guide

Head over to the Build Guide for the original prototype

Remixes

• @ijnekenamay has created a custom PCB for the project using mostly off the shelf components

Experimental Features

• There is a basic remote UI over USB available as a custom build (because enabling USB requires an extra 6kB of ram) that can be enabled using the USB_REMOTE_UI flag in the top level CMakeLists file. There is currently no documentation of the protocol except for in the diff of the PR. An initial client app is also available for testing.

MANUAL

Head over to the Manual

Get involved!

You can join the fun by following our contributing guide.

Development

Head over to the Developer Guide

Want to know more

I posted an article about the development of the picoTracker at democloid.com and one about the portable version.