Digispark-1Button-Keyboard.ino

#include "DigiKeyboard.h"

bool pressing = false;

void setup() {
  pinMode(0, INPUT);
  digitalWrite(0, HIGH); // Pull Up
}

void loop() {
  if (digitalRead(0) == LOW && !pressing) {
    pressing = true;
    DigiKeyboard.sendKeyPress(KEY_D, MOD_GUI_LEFT);
  }

  if (digitalRead(0) == HIGH && pressing) {
    pressing = false;
    DigiKeyboard.sendKeyPress(0, 0);
  }
}