Hardware accessories

Notes about USB and Bluetooth hardware accessories.

Whatever happens, there must be an external input protocol so the app knows what to do with inputs from devices.

Protocol option a

• Task requires a stopwatch-like ability (start, stop, lap, reset)
• A hardware device such as a button box sends unusual keystrokes to the app, eg on this device the red button sends ctrl-A.
• Task setup file includes an instruction that if keystroke ctrl-A is received, this means press 'start' button on screen.

Advantage: Means a button press can mean different things in different tasks.

Disadvantage: Operators may have different button boxes, red button on this one sends ctrl-A, but that one sends ctrl-Z

Protocol option b

• Task requires a stopwatch-like ability (start, stop, lap, reset)
• A library of keypress meanings is established where it is known that ctrl-A always means timer start.

Advantage: No setup configuration needed (ie a timer component in the app is hard coded to know that if ctrl-A is received this always means stopwatch-start). Transparent support of different devices.

Disadvantage: Means a physical device eg button box will either have only one purpose, (eg stopwatch) or needs some more complex switching ability to convert between 'modes', ie in mode a (stopwatch) a red button press sends ctrl-A but switch it to mode b (counter) and a red button press sends ctrl-X which in the common protocol means increment current count by one.

Best option?

Despite its disadvantages, Option a is probably the most flexible, is simpler to control settings in software than hardware. A list of 'recommended' button presses could be published so it would be 'normal' for a red button to always send ctrl-A.

Cheap and simple keyboard emulators (eg for button boxes)

• teensy