BuzzerKeyboard

Arduino-based HID (keyboard) with some big buttons to control e.g. web applications.

Motivation

I was looking for a simple solution to trigger functions of a web application by not using a normal keyboard or mouse. My main use case is a badminton tournament sióftware (see https://github.com/gromeck/Turnier).

Requirements

The requirements for the BuzzerKeyboard are as follows:

• The keyboard should be connected via USB to a PC and should be recognized as a standard keyboard by the PC (without any driver or configuration).

• The keyboard should work without any additional power supply beside the USB power.

• The keyboard should be prepared to support up to 5 buttons.

• Each button should send the corresponding keycode whenever the button is pressed. Releasing a button should not send a keycode.

  Button	Color	Keycode
  A	red	j
  B	green	k
  C	yellow	l
  D	blue	m
  E	white	n

• Each button should support an LED which is on during the time the button is pressed.

• An activity LED should be on permanently. Whenever a keycode is sent, the activity LED should indicate this by switching off for a short period.

• The buttons of the keyboard are named A, B, C, D and E.

• By pressing the button A for 5 seconds, the configuration mode is enabled.

• The configuration mode is indicated by a blinking activity LED.

• In the configuration mode, the buttons are used as follows:

  Button	Color	Function
  A	red	leave the configuration mode
  B	green	set the keycode modifiers to [ALT]
  C	yellow	set the keycode modifiers to [ALT]+[SHIFT]
  D	blue	set the keycode modifiers to [ALT]+[CTRL]
  E	white	set the keycode modifiers to [NONE]

• Whenever an configuration function is changed, the corresponding button should indicate the change by flashing.

Solution

An Arduino device should be used to implement the requirements. ATmega32U4 based boards (like Arduino Leonardo, Pro Micro, Due or Zero boards, 3.3V 8 MHz) are able to act like a USB human interface device (HID).

The Arduino makes use of the Keyboard libraries, which let the Arduino act like a keyboard to the connected computer.

As the BuzzerKeybord sends keycodes in combination with a configurable modifier, the web application has only to define access keys.

I used push buttons with microswitches. You will find these by searching vor "arcade push button" in your favorite electronic stores.

In the directory Test you will find a HTML test code.

Result