I have been kicking around this idea for some time, but I would like to see if anyone else has any interest. As well, I am wondering if someone is already doing this, or something like it. I need not reinvent the wheel.
The problem: Devices need to display user feedback more complex than simple (human-read) led-blink-codes can supply. Some devices are too small, or need to be made too inexpensively/simply to incorporate an lcd or similar display.
The idea: Develop an open standard communication protocol using light (via led, or similar) and morse-code (or similar encoding) that can be easily read via a smartphone app. Basically, the user can point their phone's camera at a blinking led on the device and can obtain diagnostic/feedback/other info from it. If this was a standard of some kind, what I am envisioning is that just about any device could incorporate this protocol as a simple and effective means of user feedback. I would think you could supply a great deal of information very easily using a method like this. Future versions of the protocol could even allow for two way communication (perhaps by way of flashing the phone's flash bulb).
A practical example of this might be something like this: You have a device that outputs a variable amount of current to an LED driver based on temperature. In a simple device like this, you could easily have more money invested in the lcd display than in the other components combined. You press a button and aim your smartphone, equipped with the morse-reader app at the led, the led starts flashing (a sync message, then the output). A message is displayed on your screen, "Current temp is 98 degrees, output is 85%, press button labeled 'button 2' to change parameters." At this point, an number of subroutines could occur.
Anyway, please let me hear your thoughts. It seems like having an open platform for providing feedback from inexpensive devices would be very helpful to many of the projects we work on with arduino. I really think that if this is to work, it would need to be an open collaborative project instead of something proprietary.