Doepfer

> It's very simple. The center pin of each switch is connected to an
ADC pin
> of the microcontroller. In the center position the voltage generated
by the
> switch is ~ 2.5V (nothing but a voltage divider made with two resistors
> connected to +5V and GND). In the left/right position the terminal is
> connected to +5V or GND. If you apply a voltage in the range 0...+5V
to the
> center pin of a switch (and make sure that the switch is in the center
> position) you can switch between the 3 function with an external
voltage.
> But you have to pay attention that no negative voltage and no
voltage beyond
> +5V is applied. In this case the microcontroller will be damaged.
Protection
> diodes connected to GND and +5V in combination with a serial
resistor (~1k)
> should be sufficient.

am i right to assume that a diode has no value that needs to be
correct - any old diode from conrad will do?

thanks, stu