How can a USB keyboard emulator (TrinketKeyboard) type Unicode characters?

Question

I've got an Adafruit Trinket microcontroller set up using this USB keyboard tutorial, and it works great.

I'd like to set up my project to type a shruggie ( ¯\_(ツ)_/¯ ) when I press a hardware button.

My naive solution was:

TrinketKeyboard.print("¯\_(ツ)_/¯");

But that only printed the underscores, parentheses and slashes, not the "hands" or the "face."

Is there a standard keyboard input method I could use so this device, when plugged into any Mac, will type out a string that includes Unicode (specifically Katakana) characters?

An ideal solution does not require configuring the machine before plugging this widget in, and doesn't require changing state on the machine -- although I'll take what I can get! :) (e.g., configuring Japanese keyboard support and toggling input source -- all of which is done blind since the computer can't give feedback to a lowly keyboard -- is un-ideal.)

Answer 1

You could hack it.

1. Make it press CMD+SPACE
2. type terminal.app
3. press ENTER
4. type echo -e "\xC2\xAF\\_(\xE3\x83\x84)_/\xC2\xAF" | pbcopy
5. press ENTER
6. press CMD+Q
7. press CMD+V

though the user would see a terminal window for a second.

Answer 2

It depends entirely on the operating system you are working with. The Arduino is merely a keyboard. It sends keystrokes. Whatever keystrokes your operating system will accept to generate unicode character are the keystrokes you have to program the Arduino to send. Most likely there is some combination of ALT-GR + keypad numbers that will do the trick.

For OS X it looks like the only possible way is to change the input settings on the computer to allow "Unicode HEX" entry.

• https://discussions.apple.com/thread/1899290?tstart=0

There is no other way of doing it. As I say, the Arduino is just a keyboard. It is subject to the same rules as any other keyboard. You can only type things that can be typed. If you need to type other things the OS has to be made aware that you want to type those things through settings.