I am programming an embedded system and, as a safety feature, when a message (to which the user has to react) is displayed on the screen, a (monotone) beeper can be triggered.
As we have 3 different tipes of messages (questions/warnings/errors) that are already differentiated by color (green/yellow/red), I am evaluating to apply a similar distinction to the beeper by implementing 3 different sequences.
Are there studies or references on which kind of sequences (e.g., long vs short beeps, intermittent beeps) are more user-friendly in such a situation, i.e. sequences that will alert the user that a green/yellow/red message is being displayed?
I am obviously assuming that such "better" sequences exist at all, if they do not I understand that I will have to come up with my own definitions