Loek Boermans and a student of him created a pneumatic device which was yaw-free as well.
The title of the article is "Improvement of an Artificial Stall Warning System for Sailplanes", and it was presented in 2006 at the OSTIV congress in Eskilstuna, Sweden.

Most of these efforts focus on stall-warning, but for the most part AoA is rather linear with CL. You could calculate CL like so:

CL = (2* m * g)/(rho * v^2 * S)
m = mass in kg
g = gravitational constant in m/s^2 (9.81 approx)
S = wing surface in m^2
rho = air density in kg/m^3
v = true airspeed in m/s

You can also swap rho/v for rho0 (air density at sea level, roughly 1.225) and v_e (equivalent airspeed).