How to use Teensyduino to send cmd + enter

Recently we purchased a bunch of Teensyduino powered buttons for a trivia game we were building for a client’s convention as a fun learning experience. Now that the conference is through, the buttons are sitting unused, and my boss asked me if I could reprogram one of them so he could use it to send emails through Outlook on Mac.

It was a fun little exercise since I’ve never worked with programming Teensyduinos before. It turned out that this wasn’t so complicated to accomplish. I figured I’d share the script in case anyone else would find it useful.

int key1 = KEY_ENTER; 

int spacesAllowed = 1;

void setup() {
  Serial.begin(9600);
  pinMode(10, INPUT);
  digitalWrite(10, HIGH);  // C7
}

void loop() {
  if (digitalRead(10) == LOW && spacesAllowed > 0){
    Keyboard.set_modifier(MODIFIERKEY_GUI);
    Keyboard.set_key1(key1);
    Keyboard.send_now();
    delay(5);
    spacesAllowed = 0;  // no  spaces allowed anymore
  }
  if (digitalRead(10) == HIGH){
    Keyboard.set_modifier(0);
    Keyboard.set_key1(0);
    Keyboard.send_now();
    delay(5);
    spacesAllowed = 1;  // button is up again
  }
}

If you need to send through Outlook on Windows, change the line

Keyboard.set_modifier(MODIFIERKEY_GUI);

to

Keyboard.set_modifier(MODIFIERKEY_CTRL);