IR decoder on an Arduino Uno

// IR decoder: the Elegoo kit's infrared lesson with the IRremote library.
// Press a button on the handset and the serial monitor names it.
//
//   receiver  OUT -> pin 11, GND -> GND, VCC -> 5 V
//   handset   its IR pin to the receiver's IR pin (the beam)
//
// IrReceiver.begin() starts timer 2 sampling pin 11 every 50 microseconds in
// the background, as the library does on an Uno, so decode() never waits: it
// returns true once a whole frame has arrived. The handset speaks NEC, so
// decodedIRData.command is the button's one-byte code and the address is 0.
// Holding a button sends a short repeat frame every 110 ms, which the library
// flags as a repeat.
//
// Timer 2 belongs to the library now, so tone() and analogWrite() on pins 3
// and 11 are not available, as on a real Uno.
//
// Things to try. Hold a button and watch the repeats. Then add a case to
// switch on the command and light the Uno's LED from a button.

#include <IRremote.hpp>

const int RECEIVER_PIN = 11;

const char *nameOf(uint8_t command) {
  switch (command) {
    case 0x45: return "CH-";
    case 0x46: return "CH";
    case 0x47: return "CH+";
    case 0x44: return "PREV";
    case 0x40: return "NEXT";
    case 0x43: return "PLAY/PAUSE";
    case 0x07: return "VOL-";
    case 0x15: return "VOL+";
    case 0x09: return "EQ";
    case 0x16: return "0";
    case 0x19: return "100+";
    case 0x0D: return "200+";
    case 0x0C: return "1";
    case 0x18: return "2";
    case 0x5E: return "3";
    case 0x08: return "4";
    case 0x1C: return "5";
    case 0x5A: return "6";
    case 0x42: return "7";
    case 0x52: return "8";
    case 0x4A: return "9";
    default: return "?";
  }
}

void setup() {
  Serial.begin(9600);
  IrReceiver.begin(RECEIVER_PIN, ENABLE_LED_FEEDBACK);
  Serial.println("IR receiver ready");
}

void loop() {
  if (IrReceiver.decode()) {
    if (IrReceiver.decodedIRData.flags & IRDATA_FLAGS_IS_REPEAT) {
      Serial.println("  (repeat)");
    } else if (IrReceiver.decodedIRData.protocol == NEC) {
      Serial.print("0x");
      Serial.print(IrReceiver.decodedIRData.command, HEX);
      Serial.print("  ");
      Serial.println(nameOf(IrReceiver.decodedIRData.command));
    } else {
      Serial.println("not NEC");
    }
    IrReceiver.resume();
  }
}