Description

The default Arduino keyboard library calls sendReport every time when switch is pressed or released.
That's very inefficient, so you can speed up the latency by only calling sendReport once at the end after a key scan.

How to Use

#include <Keyboard.h>
KeyReport _keyReport;

void setup() {

  pinMode(2, OUTPUT);
  pinMode(3, OUTPUT);
  pinMode(4, OUTPUT);
  pinMode(5, OUTPUT);

  pinMode(8, INPUT_PULLUP);
  pinMode(9, INPUT_PULLUP);
  pinMode(10, INPUT_PULLUP);
  pinMode(16, INPUT_PULLUP);
  pinMode(14, INPUT_PULLUP);
  pinMode(15, INPUT_PULLUP);

  digitalWrite(2, LOW);
  digitalWrite(3, LOW);
  digitalWrite(4, LOW);
  digitalWrite(5, LOW);

}
void loop() {
  if(!digitalRead(8)){
    _keyReport = Keyboard.press_key(_keyReport, KEY_F10);
  }
  else if(digitalRead(8)){
    _keyReport = Keyboard.release_key(_keyReport, KEY_F10);
  }
  if(!digitalRead(9)){
    _keyReport = Keyboard.press_key(_keyReport, '-');
  }
  else if(digitalRead(9)){
    _keyReport = Keyboard.release_key(_keyReport, '-');
  }
  if(!digitalRead(10)){
    _keyReport = Keyboard.press_key(_keyReport, '[');
  }
  else if(digitalRead(10)){
    _keyReport = Keyboard.release_key(_keyReport, '[');
  }
  if(!digitalRead(16)){
    _keyReport = Keyboard.press_key(_keyReport, '\'');
  }
  else if(digitalRead(16)){
    _keyReport = Keyboard.release_key(_keyReport, '\'');
  }
  
  ......
  
  Keyboard.sendReport(&_keyReport); //only call once at the loop's end
}