Arduino an Android. USB? Bluetooth? And How.

I have a Minix x7 Android KitKat device and a Boarduino V2 with a Atmega328.
I have a little skatch to switch my light per 443mhz transmitter.

Sketch :

#include <RCSwitch.h>RCSwitch mySwitch = RCSwitch();int led = 13;void setup() { pinMode(led, OUTPUT); Serial.begin(9600); // Transmitter is connected to Arduino Pin #10 mySwitch.enableTransmit(5); // Optional set pulse length. // mySwitch.setPulseLength(320); // Optional set protocol (default is 1, will work for most outlets) // mySwitch.setProtocol(2); // Optional set number of transmission repetitions. // mySwitch.setRepeatTransmit(15); Serial.write(“Was willst du tun?”); Serial.write(’\n’); Serial.write("------------------------------------"); Serial.write(’\n’); Serial.write(“A = LICH Ein”); Serial.write(’\n’); Serial.write(“B = LICH Aus”); Serial.write(’\n’); Serial.write(“C = LEDs Ein”); Serial.write(’\n’); Serial.write(“D = LEDs Aus”); Serial.write(’\n’); Serial.write("------------------------------------"); Serial.write(’\n’); }void loop() { if (Serial.available() > 0) { int inByte = Serial.read(); switch (inByte) { //Lcht An case ‘1’: Serial.write(“Schalte Licht ein …”); digitalWrite(led, HIGH); mySwitch.switchOn(“11111”, “10000”); delay(100); mySwitch.switchOn(“11111”, “10000”); delay(100); mySwitch.switchOn(“11111”, “10000”); digitalWrite(led, LOW); Serial.write(“OK”); Serial.write(’\n’); break; //Licht Aus case ‘2’: Serial.write(“Schalte Licht aus …”); digitalWrite(led, HIGH); mySwitch.switchOff(“11111”, “10000”); delay(100); mySwitch.switchOff(“11111”, “10000”); delay(100); mySwitch.switchOff(“11111”, “10000”); digitalWrite(led, LOW); Serial.write(“OK”); Serial.write(’\n’); break; //LED An case ‘3’: Serial.write(“Schalte LEDs ein …”); digitalWrite(led, HIGH); mySwitch.switchOn(“11111”, “00010”); delay(100); mySwitch.switchOn(“11111”, “00010”); delay(100); mySwitch.switchOn(“11111”, “00010”); digitalWrite(led, LOW); Serial.write(“OK”); Serial.write(’\n’); break; //LED Aus case ‘4’: Serial.write(“Schalte LEDs aus …”); digitalWrite(led, HIGH); mySwitch.switchOff(“11111”, “00010”); delay(100); mySwitch.switchOff(“11111”, “00010”); delay(100); mySwitch.switchOff(“11111”, “00010”); digitalWrite(led, LOW); Serial.write(“OK”); Serial.write(’\n’); break; default: Serial.write(“Versuch es nochmal …”); Serial.write(’\n’); }}}
Now i want to controle ist with my Android device.
I tried to use USB but if I richtig I have to mod the Kernel.
Is there an easier way? BLUETOOTH? What Module need I?