This design, while very different from the released module, was the start of everything: four lanes, some basic transport, quantization, and a simple interface. But what if it could do more?

This prototype introduced cartesian sequencing and the LED grid that  was the signature of the original. Mimetic Digitalis has been a huge success, making its way into studios and performances around the world. But with nearly 10 years since the original prototype and a lot of time to play with the first iteration, we've had a lot of time to think about what else could be done in a similar package.

We’ve always loved the original design – it’s so much fun for jamming, and its flexibility is unmatched. That said, there were always things we wished it could do; with nearly seven years passing since its original release we’ve had quite a bit of time to think, and the processors we have have had plenty of time to get better. The original was built on one of the first MCUs we used (MSP430) and there’s just not a ton of power there. It also can’t be updated by users. The new generation of processors we use can all be field updated, and we figure maybe it was time for the MD to grow up.

You’ll notice quite a few similarities between this mockup and the final product. 

In the end, we decided that we really wanted the final module to be the same 10 HP footprint as the original, and we slimmed down the design to make everything fit in the same package. This allowed the new version to be a drop-in replacement for users of the original, and kept us from making an entirely different sequencer – we didn’t want to lose the magic of the first version. We also really wanted to keep the new version price-competitive with the old one, and adding HP is a sure way to add cost.

Prototyping

Once we had a paper concept of what we wanted the hardware to do, we could start developing a prototype. The first prototype was a bit of a challenge. We wanted to use a processor that we had lots of stock of (a choice that would later haunt us), but needed to add additional memory. This proved to be… challenging, on both the hardware and software side, and required lots of firmware touchups, hardware modifications, and even a daughterboard we designed when we were well into development (in purple below). 

By the time we finished with all the bits the prototype needed, we had more things running on the SPI peripheral on the CPU than we had SPIs. Stephen then had to figure out how to effectively multiplex two things on a single SPI, which was not a fun task and added a lot of complexity to the code.

The original prototype, held together by solder, hope, and dreams.

Despite the… questionable mechanical stability of this first prototype, it worked wonderfully and allowed us to get 95% of the way done with prototyping the firmware. It also showed us what changes we needed to make – like removing some unnecessary LEDs and moving some controls – which reduced the final cost and improved usability. 

Final hardware

Most products take multiple hardware revisions before we’re ready to go to press, so to speak. Mimetic Digitwolis was a rare one where we only needed one prototype. This was largely driven by the fact that this one lent itself well to modifications (see above)...We were able to test all the changes in place on the first version. Once we were satisfied, we sent it off to be built, made some final tweaks to the hardware, and got ready to put it into the world.

Firmware development gets complicated sometimes.

Of course, there’s a bit more to the story when it comes to the firmware development. Despite its compact size and relatively straightforward interface, Mimetic Digitwolis ended up being one of the most complex firmwares we’ve ever worked on due to its enormous functional potential.

In a few weeks, we’ll share a bit more behind the scenes of the firmware development.