Breathing LED for Arduino or AVR C. Adafuit profile. Data in flash.

breath.c

#include <avr/pgmspace.h>

const PROGMEM uint8_t breath_data[] =  {
  64, 68, 72, 76, 81, 85, 90, 95, 100, 105, 110, 116, 121, 127, 132,  138, 
  144, 150, 156, 163, 169, 176, 182, 189, 196, 203, 211, 218, 225, 233, 241, 249,
  255, 249, 241, 233, 225, 218, 211, 203, 196, 189, 182, 176, 169, 163, 156, 150,
  144, 138, 132, 127, 121, 116, 110, 105, 100, 95, 90, 85, 81, 76, 72, 68
};

#define BREATH_LEN (sizeof( breath_data) / sizeof( *breath_data ))


uint8_t breath(uint8_t step) {

  uint8_t brightness = pgm_read_byte_near( breath_data + step);
  return brightness;
  
}