Probably just conceptual.
Yes, it is conceptual.
Would be a fun programming project
Definitely! I'm already obsessed (my OCD just woke up) ...
I thought about the IDs but I'm still wondering HOW identify each key without making it expensive.
IF the uC ports used to scan the keyboard matrix were ALL analogic ports I would be able to add different resistor values to each switch then I would be able to measure the output voltage and then identify the pressed switches.
Why different resistor values and how measuring the output voltage would identify the pressed switches?
Easier to explain with the puzzle below, the idea is the same:
"You are given ten bags each containing ten marbles. All of the marbles weigh ten units each, except for one of the bags contains ten marbles from the wrong batch. Those ten marbles weigh only 9 units each. You do not know which bag contains the wrong marbles. In only one weighing using a scale which can read out digital weight, determine objectively which bag contains the wrong marbles."
It does make sense?
I can't think on any other component cheaper than a resistor (1% resistor, the value is important).