#include <M5Core2.h>
#include "BluetoothSerial.h"

BluetoothSerial SerialBT;

void setup() {
   SerialBT.begin("M5Stack-Vojta"); //Bluetooth device name
   M5.begin();
}

void loop() {
   if (SerialBT.available()) {
     char ch=SerialBT.read();
     if(ch=='a' || ch=='A')
        M5.Lcd.fillScreen(WHITE);
     if(ch=='b' || ch=='B')
        M5.Lcd.fillScreen(RED);
     if(ch=='c' || ch=='C')
        M5.Lcd.fillScreen(GREEN);
     if(ch=='d' || ch=='D')
        M5.Lcd.fillScreen(BLUE);        
   }
   M5.update();   // update button state
   if(M5.BtnA.isPressed()) {
      SerialBT.println("Key A");
   }
   if(M5.BtnB.isPressed()) {
      SerialBT.println("Key B");
   }
   if(M5.BtnC.isPressed()) {
      SerialBT.println("Key C");
   }
   delay(100);
}