LED corresponding to angle on ADXL345

main.cpp

#include <Arduino.h>

#include <Wire.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_ADXL345_U.h>
#include <Adafruit_NeoPixel.h>
#include <math.h>

// adaFruit led parmeters
#define PIN 0
#define NUM_LEDS 8
#define ON_LEDS_COUNT 2
#define DELAYVAL 100 // optimal against too hard flickering

const int ZERO_NUM_LEDS = NUM_LEDS - ON_LEDS_COUNT;
Adafruit_NeoPixel strip(NUM_LEDS, PIN, NEO_GRB + NEO_KHZ800);
sensors_event_t event;
Adafruit_ADXL345_Unified accel = Adafruit_ADXL345_Unified(12345); // Assign a unique ID to this sensor at the same time

void loop(void)
{
  accel.getEvent(&event);

  float y = event.orientation.y;
  float x = roundf(event.orientation.x);
  int deg = abs(atan2(y, x)) * 180 / M_PI;
  int gyroOrientationOffsetX = -ZERO_NUM_LEDS;
  int pos = map(deg, 0, 180, 0, ZERO_NUM_LEDS);
  Serial.printf("[deg: %d][pos: %d]\r\n", deg, pos);

  strip.clear();
  int pixelIndex = abs(pos + gyroOrientationOffsetX);
  for(int i = 0; i < ON_LEDS_COUNT; i++) {
    strip.setPixelColor(pixelIndex + i, strip.Color(0, 150, 0));
  }
  strip.show();
  delay(DELAYVAL);
}

void setup(void)
{
  Serial.begin(9600);
  Serial.println("Accelerometer Test");
  Serial.println("");
  strip.begin();

  if (!accel.begin())
  {
    Serial.println("Ooops, no ADXL345 detected ... Check your wiring!");
    while (1)
      ;
  }

  accel.setRange(ADXL345_RANGE_16_G);
  Serial.println("");
}