It's a few weeks now since I finished the PolyMod prototype, and my head is now clear enough to think about what comes next. Here's a list of things that I'm imagining will feature in version two:

• Easier to build
  • Use PCB's rather than stripboard
  • Design a 3D-printable case and 3D-printable module faceplates (while retaining the option of making it out of wood if that's your thing)
• A bigger/better/extensible library of modules
  • A publicly editable database of modules, with version numbers, descriptions, graphical previews, etc
  • An online (open source) tool to generate custom Teensy code with your personal selection of modules included
  • Adding these features will move this project slightly closer to the appeal of modular synths, in that there could end up being a large and diverse variety of quirky modules to choose from
• A display and menu system
  • This is controversial . There was something really appealing about the fact that the first version didn't have a menu system - having to navigate through a maze of sub-menus is one of the worst things about modern synths like the MicroKorg, but... there are some really cool features I could add if I had a simple menu system, such as:
  • Saving/retrieving patches, something that you can't do on a regular modular synth
  • Changing the "identity" of a given physical module without having to resolder anything - you could use the menu to let the system know that module #13, for example, is no longer a low-pass filter but is instead an eight-step sequencer
  • Maybe onboard audio recording? That would be pretty sweet, and within the Teensy's capabilities
  • I promise that you won't HAVE to use the menu system unless you're trying to alter a module's identity, which I think is a fair compromise. I realise I'm talking to myself now
• External audio inputs would be pretty sweet
• Better module design
  • Separating the design of the physical modules (many of which are similar or identical) from the design of the faceplates/front panels (which vary hugely), making it much easier to try out different modules by simply switching out the front panels (or even just relabelling them)
  • Allow double/triple width designs for more complex modules
  • LEDs!
  • A less fiddly way of mounting the modules (currently easy to be off by one pin, causing a short circuit)
  • DIP switches to give modules custom ID numbers
• A MIDI input instead of a built in keyboard (probably)
  • The keyboard part of the previous project was a stupid idea - it was loads of work for something that works much worse than a normal keyboard
  • Doing away with a traditional keyboard will make the synth super compact
  • I might do a simplified keyboard instead
• Future-proofing / modular design
  • If possible, I would like to design the new system so that it can be upgraded to Teensy 4.0 or a different processor in the future
  • It would be nice if the system's main "brain" was properly separated from the part where you plug modules in. Ideally, I would like an endlessly extensible system, where you could connect an unlimited number of modules, perhaps in blocks of 8 or 16. Maybe this is something for the more distant future
• A more sensible form factor? Maybe something that could somehow integrate with Eurorack would be cool
• Maybe use cheaper patch cables/sockets
  • It would be good to further bring down the cost of building the PolyMod
  • The 3.5mm cables and sockets I used on the previous version have two possible connections (nominally signal and ground), which makes them overkill for this project, where I only need one connection. I could happily get away with just using breadboard jumper wires and female headers
  • Using 3.5mm cables is also confusing because it falsely implies Eurorack compatibility

Okay, that's enough typing. I suspect this new iteration will be different enough that I should make a new Hackaday project for it, so stay tuned!