Winterbloom Sol Codes/Firmwares

I got my @winterbloom Sol a while back, and while my audio gear has been out of commission, I’ve been working on some firmwares for it. Most of them are pretty well in the prototyping phase, but I figured it couldn’t hurt to discuss concepts and maybe provide a place for others to share.

SeqPal 0.4.1

SeqPal is a simple, configurable firmware for use with sequencers. It allows assigning MIDI channels to CV/gate pairs, or just gate outputs, on the Sol, and allows using a Sol CV output as a gate output if needed. It also supports scaling its output voltage for the MODEL input of Plaits by Mutable Instruments, to facilitate using Plaits as a percussion voice.

SeqPal 0.41 was released on January 21, 2021, and requires the Sol libraries from October 3, 2020. Download it here.

DrumBud 0.1

This is an extension of the pseudo-gate feature of SeqPal, designed to turn Sol into an 8-trigger percussion extender, especially for use with the Beatstep Pro’s upper (non-CV) row of drum pads.

As with the SeqPal, it’s fully configurable, but rather than one MIDI channel per output, it’s designed to be used with existing drum sequencers on a single MIDI channel. Download it here. As with SeqPal 0.2, it requires the October 3, 2020 updates to Sol’s libraries.

Current Projects

I’m also working on a couple of other firmwares, primarily meant to be used with either ORCA or the Beatstep Pro. My current project is to make a bank of LFOs and rhythm generators controlled by the BSP in control mode. Let me know what you’d be interested in seeing, either as updates to the SeqPal or in wholly new firmwares!


Ooh, thanks for posting, looking forward to trying out SeqPal.

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I created a firmware+max4live patch to control/change behavior of the cv outs:

It’s deff super beta right now, and there’s a bug with the clock outs but it’s works for what I need right now :stuck_out_tongue:


Just updated SeqPal 0.2 to take advantage of the new Sol libraries from a few days ago, so it’s now fully customizable!


Added my new firmware, DrumBud, for all your drum sequencing needs.


Updated SeqPal to react properly to CC All Notes Off.


Updated SeqPal to translate MIDI notes in a 16-note range into voltages corresponding to the 16 models of the Plaits macro-oscillator. This means you can plug a Sol CV/Gate channel directly into Plaits’ MODEL and TRIG inputs and use it as a percussion engine.


The recent Blitz City DIY (aka Liz Clark) interview with Thea Flowers of Winterbloom is incredible. Thea talks about how she came to design her modules, working with CircuitPython, design decisions, the iterative design process, being self-taught, how to get into module design, and lots more. I learned a lot.

Edit: Oops, I didn’t think this through. I didn’t see another Winterbloom thread and posted here, but maybe this should be a separate thread rather than in Nora’s firmware thread?


We can definitely have a Winterbloom modules thread, if that’s how things are usually organized around here. (I’m still not sure.)


Hi! I’m sending CC values from Pure Data to Sol. Here is a demo where the output of Sol goes into an Arturia Minibrute. Code is up on GitHub but you can see here what the ins and outs are:

Input CC
CC16: Clock Division
CC17: Octave

Output CV
CV A: Pitch CV based on a random note
CV B: Sine LFO
Gate 1: Gate on/off for the note
Gate 2: Trigger on clock division

It’s very fun to customize this module, so I’ll keep posting stuff here :slight_smile:


I went ahead and updated SeqPal to be a little friendlier to non-sequencer use cases - specifically, keyboard playing. Now, it keeps track of how many note on commands there have been (up to a limit, default 4) and only actually turns a channel off when that many note off commands have been received. This means keyboard players will have a better time.

Made an unipolar LFO with variable frequency whose shape bends from triangle to pulse via CC. Output can also be attenuated. Get the code here! There is also a simple Pd patch to test it.


A newer version can be found here: Script for Sol & Pure Data patch. There are now two LFOs with same waveshaping capabilities, but [LFO a] can be influenced by [LFO b] for complex modulations while [LFO b] gives a simple waveform output.

Have fun!


Just started my own little repo of Sol scripts. Only one script in there at the moment, a very specific MIDI notes to Plaits drum models converter (which is nowhere near as accomplished as @NoraCodes DrumBud linked to above in this thread). Done more as a learning exercise. Thanks!


Super neat, I’ll be watching that repo with interest :slight_smile:

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