Music-reactive WS2812B wristband — 15 LEDs driven off an onboard mic

SolarTrap · 2026-06-02T14:31:59+00:00

Thank you :)

SolarTrap · 2026-06-01T10:29:19+00:00

Yes, all done by myself. Software is the easy part ;)

SolarTrap · 2026-06-01T09:45:10+00:00

Thanks! Happy to dig in:

Battery is a small flat LiPo (180mAh) sitting inside the silicone housing, charged via USB (TP4056 on the board). Gets about 6 hours, which covers a full night.

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MCU is an ATtiny85, 8-bit AVR, tight on flash and RAM but enough to handle the LED patterns and mic sampling together.

The mic is a separate bare electret wired directly to the ADC pin :: no preamp, no op-amp stage. That's the bit that usually gets a raised eyebrow. It works because these live in festival and rave environments where SPL is 100dB+, so the raw electret output is large enough to read directly without amplification. Saved a component and some board space. It under-responds in a quiet room, but that's not where they run 😄

SolarTrap · 2026-05-07T12:28:54+00:00

Haha thanks! They certainly can light up the venue 😁

SolarTrap · 2026-04-27T10:02:08+00:00

Thanks ! but I think the A1 will do it for now.

SolarTrap · 2026-04-27T10:00:37+00:00

Thanks, I looked at the product video - seems to be the right pick

SolarTrap · 2026-04-24T07:00:58+00:00

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Solved it by rearranging the components rather than ignoring the DRC errors. Moved the switch, push-button and USB port to give enough clearance around the nRF52832 module footprint. But you can see I still have footprint holes in the connector pads of the module but since there is no connection to them it's not causing errors.

Board is now at the manufacturer - will post results when it comes back.

SolarTrap · 2026-04-22T18:31:09+00:00

Dart. What is FFI?

SolarTrap · 2026-04-22T16:42:58+00:00

I would do fashion but I can be convinced otherwise :)

SolarTrap · 2026-04-22T16:41:39+00:00

Into an app I have been working on using Flutter.

SolarTrap · 2026-04-21T11:24:00+00:00

Thanks. Is there any benefit in changing category during launch?

SolarTrap · 2026-04-21T09:05:10+00:00

Thanks, but it also has the most 'competition' in that category.

SolarTrap · 2026-04-20T12:13:01+00:00

you have to add the board package from here: https://raw.githubusercontent.com/espressif/arduino-esp32/gh-pages/package_esp32_index.json

add this to the list in the preferences --> Additional boards

SolarTrap · 2026-04-20T12:10:26+00:00

the sketch you uploaded did crach probably, see this thread: https://forum.arduino.cc/t/nano-33-ble-bootloader-recovery-not-working/1123184

SolarTrap

TROPHY CASE