Michael Black schrieb:
YOu can't get much simpler than the original Macintosh mouse. The mechanical wheels, the optocouplers, the 339 comparators to sharpen up the signals, and the pushbuttons.
There was one design that is even simpler -- just the optocoupler and pullup resistor. I don't remember if they skipped the LM339 to save money, or if it has been added later to improve the slew rate of the output signals.
Patrick