Minimal Key Calculator

[PANAMATIK]

(03-13-2015 08:17 AM)Gerald H Wrote:  What could be the least number of keys needed to reproduce all the functions of, say, the HP 35S keyboard?

The ENTER key.

If you press ENTER repeatedly with special timing gaps you can enter 2^6 different codes with a maximum of 4 key presses each. This is more than sufficient for the HP35S 43 keys. The first ENTER is the start bit followed by 6 bits key code. With 2 baud, that is a maximum one keystroke per second, you can enter 100 program steps in approximately 400 seconds.

Even less keys needed by speech entry.

Bernhard