stall detection without encoder?

Hi programming Einsteins,

don't know if this is old hat. Chanced upon this site:

http://www.controleng.com/archives/2000/ctl0601.00/000600.htm

Extracted from the above site:

<Stall detection without a formal feedback device is a target for
holding down costs at several manufacturers. Parker Hannifin,
Compumotor Div. (Rohnert Park, Calif.) claims its Gemini GT is the
first stepper drive with an encoderless technique to sense a stalled
motor—as well as the industry's only fully digital stepper drive.>
<A software algorithm acts as the "sensor." It monitors voltage and
current signals passing between the step motor and drive. By
analyzing the signals, and comparing their amplitudes and frequencies
with known values for normal step motor behavior, a stall condition
can be recognized. The stall threshold sensitivity is user
adjustable. >

Is this a fertile area for the hobby programming aficionados on the
list to try their programming skills?

Peter