> > This function has been replaced by digital potentiometers
>
> How do you make a mechanical servo with digital pots?

I've been daydreaming about this recently

A project involves setting the PIC to output PWM with variable
duty cycle, frequency, voltage, burst length and inter-burst interval.
It's akin to a TENS unit

One feature I really would have liked to add was the positions of
the pots stored in presets, but after looking into the cost/availability
of motorised ones, decided to try this way. Use an encoder (for
example magnetic - gear wheel and Hall Effect sensor - or optical)
to change a digital pot and an LED/LCD display showing the value
for each "pot". The PIC monitors the encoders and drives the digits.
It might be that each "pot" is self-sufficient, having a cheap PIC to
do all the functions of converting and displaying the analogue value,
then sending that to the PWM-ing PIC. Although the knobs won't
move when a preset is recalled, the display and output will be OK,
which is the main thing

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