This is heart shaped four RGB led badge:
The PCB and schematic is in this PDF file: S54MTB_led-srcek-v1r2
The Software is based on STM32F0 HAL drivers. Here is ZIP with keil uVision project. Please keep the folder structure! Source code has comments and is quite simple. One timer intterupt is driving all leds. The PWM is 1:300 for each color and there are few functions for setting the PWM or the intensity. The function for converting Hue/Saturation/Intensity id also provided in the led.c module. The result of the demo “blinky” is shown in the video above.
The badge has one LiPo cell with battery protection circuit and simple USB charger, so there should be no trouble with the empty batteries.