Swipe lamp on an Arduino Uno

// Swipe lamp: an APDS-9960 watches for a hand swiping over it, read with
// SparkFun's library, and dims an LED to match.
//
//   APDS-9960   VCC -> 3.3 V   GND -> GND   SDA -> A4   SCL -> A5
//   LED         pin 9 -> 220 ohm -> LED -> GND
//
// Four photodiodes sit behind the sensor's window, one on each side, and an
// infrared LED lights the hand. A hand swiping up reaches the up diode first
// and the down one last, so the order the four light up in says which way it
// went. Swipe up for brighter, down for dimmer, left for off and right for on.
// Every two seconds it also prints the light it sees.
//
// The arrows on the sensor swipe a hand across it; the sliders and the C
// button set the room's light.

#include <Wire.h>
#include <SparkFun_APDS9960.h>

const int LAMP_PIN = 9;

SparkFun_APDS9960 apds;
int level = 128;
bool on = true;
unsigned long lastLight = 0;

void show() {
  analogWrite(LAMP_PIN, on ? level : 0);
  Serial.print("lamp ");
  Serial.println(on ? level : 0);
}

void setup() {
  Serial.begin(9600);
  pinMode(LAMP_PIN, OUTPUT);
  if (!apds.init()) {
    Serial.println("Something went wrong during APDS-9960 init!");
    while (1) {
    }
  }
  apds.enableLightSensor(false);
  apds.enableGestureSensor(true);
  Serial.println("Swipe lamp ready");
  show();
}

void loop() {
  if (apds.isGestureAvailable()) {
    switch (apds.readGesture()) {
    case DIR_UP:
      Serial.println("UP");
      level = min(level + 64, 255);
      break;
    case DIR_DOWN:
      Serial.println("DOWN");
      level = max(level - 64, 0);
      break;
    case DIR_LEFT:
      Serial.println("LEFT");
      on = false;
      break;
    case DIR_RIGHT:
      Serial.println("RIGHT");
      on = true;
      break;
    default:
      Serial.println("NONE");
      return;
    }
    show();
  }
  if (millis() - lastLight > 2000) {
    lastLight = millis();
    uint16_t c, r, g, b;
    apds.readAmbientLight(c);
    apds.readRedLight(r);
    apds.readGreenLight(g);
    apds.readBlueLight(b);
    Serial.print("light ");
    Serial.print(c);
    Serial.print("  red ");
    Serial.print(r);
    Serial.print("  green ");
    Serial.print(g);
    Serial.print("  blue ");
    Serial.println(b);
  }
}