Post #1849703

2026-01-14 14:31 UTC

Still very much a work in progress, these earrings won't be finished for a while. There's a bunch of other features I'd like to add that take time to implement. Maybe they'll detect the beat in the music and respond accordingly. Or maybe they'll have an easy to use online IDE for new patterns to upload to the earrings and an ability to share patterns (sending the programs either via light flashes or via audio - TBD). Who knows.

Replies (1)

@ayke@hachyderm.io 2026-01-25 15:59

Managed to detect 8 different frequencies in an input signal (50 times per second) using just 1mA of current, running the chip at 4.2MHz. Pretty sure I can do better than this with some more work. But that's already potentially ~50 bytes data per second I can transfer. The algorithm I am using is the Goertzel algorithm: https://www.embedded.com/the-goertzel-algorithm/ It's a relatively unknown algorithm, but it's extremely simple and I think better suited to the task than the well known FFT family of algorithms (yes there are multiple FFT algorithms). The implementation I wrote is fixed point and uses about 8 cycles per iteration. I should write a blog post about it some time. Eventually I want to send data/programs using nothing more than a cheap microphone and some audio processing. Let's see if that's possible. #dsp

Open ##1849702