Today’s invention is an alternative to a conventional keypad.
The teeth of a metal zip, located in one’s bag or clothing, are wired electrically so that when the keeper travels to a certain position (connecting a subset of the zip’s teeth), this is recorded by a sensor attached to eg a mobile phone or even an ATM.
The zip would thus be a representation of the number line (with 0 at one end, 9 at the other and the rest of the numerals arrayed at equal intervals). The keeper need only be paused close to each numerical position for that number to be recorded.
It may be arranged that the keeper position generates an audible tone and so certain telephone numbers would then develop a cachet, based on their acting as recognisable tunes.
In this way, conventional keypads can be dispensed with (saving bulk and cost) and security enhanced -since shoulder surfing can be made almost impossible.