With the curtain call of the contest, this project is also reaching a milestone!

Since the last update, I have mounted the LDO (the TLV702), which proved sufficient to eliminate the variance in voltage drop together with the noise, yielding a clean sound. I have also tuned the sensing algorithm to reduce accidental triggering and improve sensitivity in the case of a floating ground (e.g., a portable power bank); a benefit of using a microcontroller over specialised touch-sensing ICs is the ability to fine-tune the triggering thresholds and filtering algorithms, taking into account the electrode layout and application specificities (e.g., adjacent keys tend to trigger incorrectly), without having to replace physical components.

In the hope of improving robustness, I inspected the audio bus (LSBJ) with a logic analyser. It appeared that the signals were slightly misaligned, so I adjusted the timing offsets to achieve an ideal alignment among the signals. The inline assembly block also underwent a bit of rewriting, getting rid of an excessively long nop sequence.

Before (BCK vs WS; BCK vs DATA):

After (BCK, WS, DATA):

With all that done, here it is!

This ended up missing the Madman Muntz special mentions — I guess I need to get madder 😈 (But it did get featured on the Hackaday.io Bits newsletter! 🌟) The challenge really saw exceptional creativity in every aspect — please check out the winners’ announcement and all the projects in the challenge!

Thank you for getting this far. I will make sure to update here whenever this gets further updates, but meanwhile, see you in the Tiny Games!