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LEDHat firmware

15 September 2021

OK, so, er, I built a hat with LEDs on it but we all make questionable decisions from time to time.

Should you want to make similarly bold fashion statements, this code might help.

Using a cheap STM32F031 microcontroller, a cheap ADXL345 accelerometer, and a horizontal hoop of WS2812B LEDs, this code implements a kind of "spirit level"/air bubble effect: a flash of light follows the highest part of the brim as the hat is tilted.

Bits you can steal:

  • STM32F0 timekeeping, UART stuff
  • DMA-driven WS2812B code: high-performance and background updates, and zero-flicker
  • Vector/trig code for measuring tilt direction using an accelerometer

Have fun!


Main code, WS2812/vector stuff

Copyright (C) 2015, 2021 Matt Evans

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

Other parts/credits


STM32F031 firmware for WS2812B-based amazing wearable tech







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