// Using Arduino as keyboard emulator on iOS devices (HID/Keyboard)
//
// *used Arduino Pro Micro Clone, 5v
// *selected Arduino Leonardo as board when compiling
//
// for use with iOS without complaining, modify the USBCore.h file to tell the arduino to use less usb poiwer 
// change USB_CONFIG_POWER from 500 to 100, on line 98, see below
//
//  bMaxPower in Configuration Descriptor
//   #define USB_CONFIG_POWER_MA(mA)                ((mA)/2)
// #ifndef USB_CONFIG_POWER
//   #define USB_CONFIG_POWER                      (100)
// #endif
//
// on mac the USBCore.h is located at:
//  /Applications/Arduino.app/Contents/Java/hardware/arduino/avr/cores/arduino/USBCore.h 
//
// ref: https://arduino.stackexchange.com/questions/60771/arduino-micro-draws-too-much-power-from-iphone-how-can-i-change-that
//
// tested on:
// iPhone 6 + iOS 12.4.4
// iPhone X + iOS 14.2
// 

#include <Keyboard.h>

void setup() {
  pinMode(3,INPUT_PULLUP);
}

void loop() {
  Keyboard.begin();
  if(digitalRead(3) == 0)
    {
        Keyboard.write('A');
        delay(100);
    }
  Keyboard.end();
}