I would start with two small ports in the leading edge of the wing,
with capillary tubes running to a MEMS differential pressure sensor.

Since the purpose of the device is to tell the pilot how
close the AOA is to the stall value these ports should be
placed straddling the stall stagnation point. (maybe plus-minus 1/2
inch?) Then
the pressure difference is zero at stall, at any airspeed.

The differential pressure IC can feed an LED bar graph.
This should give very good stall prediction accuracy.

Isn't there a voltage-to-LED-bar-graph IC? I seem to
remember such a thing. That would make the circuit simple.

When approaching
an accelerated stall (at higher airspeed than while landing)
the unit would tend to overestimate angle. Actually, it measures
something more like "lift reserve" than angle of attack. But isn't
that
the better quantity to report to the pilot?

Anyway. the feel of the controls is very different in these two
cases,
so I think most pilots would learn to adjust their interpretation
of the reading, as long as the yellow light comes on, then red, then
the
plane stalls.

-Jeff