led_bikewheel/led_bikewheel.ino

#include <FastGPIO.h>
#define APA102_USE_FAST_GPIO

#include <APA102.h>

#include "images.h"

const int HALL_PIN = 2;
const int ROUND_COUNT = 2;

// Define which pins to use.
const uint8_t dataPin = 10;
const uint8_t clockPin = 11;

const int num_segments = 360;
const uint16_t led_count = 28;

const uint8_t brightness = 1;

const int state_count = 4;

rgb_color color_buffer[led_count];

float passed = 0;
int current_image_index = 0;

uint8_t *current_palette;
uint8_t *current_pixels;

// Create an object for writing to the LED strip.
APA102<dataPin, clockPin> ledStrip;

void setup()
{
  Serial.begin(115200);
  pinMode(HALL_PIN, INPUT);
  pinMode(LED_BUILTIN, INPUT);
  current_palette = (uint8_t *)pgm_read_word(&images[current_image_index].palette);
  current_pixels = (uint8_t *)pgm_read_word(&images[current_image_index].pixels);
}

void loop()
{
  float start = micros();
  int count = 0;
  bool change = false;
  while (count < ROUND_COUNT)
  {
    // check HALL if turned
    if (digitalRead(HALL_PIN) == LOW)
    {
      digitalWrite(LED_BUILTIN, HIGH);
      if (!change)
      {
        change = true;
        count++;
      }
    }
    else
    {
      digitalWrite(LED_BUILTIN, LOW);
      change = false;
    }

    // calc led for last turn
    float current_diff = micros() - start;

    int state = ((float)passed / current_diff * num_segments);

    uint8_t pixel_color_index;
    uint8_t *current_pixel = (uint8_t *)&current_pixels[state * led_count];
    for (int i = 0; i < led_count; i++)
    {
      pixel_color_index = pgm_read_byte(current_pixel++) * 3;

      color_buffer[i] = rgb_color(
          pgm_read_byte(&current_palette[pixel_color_index]),
          pgm_read_byte(&current_palette[pixel_color_index + 1]),
          pgm_read_byte(&current_palette[pixel_color_index + 2]));
    }

    ledStrip.write(color_buffer, led_count, brightness);
  }

  passed = (micros() - start);
}