The method that the microchip board utilized was to control two relays. If both relays are unenergized, then the motor sees no voltage (both leads of motor shorted to ground). To spin the motor one of the relays is energized which ties the input voltage to one of the motor leads. The other lead is then tied to a current sensing resistor. To spin the motor in the other direction, the opposite relay is energized resulting in current through the motor in the opposite direction and the motor is still tied to ground via the same current sense resistor.
Knowing how much current it takes to raise/lower the window, one could use the voltage across the current sense resistor to set a trip level via analog circuitry in the place of a micro. The trip signal would then force the energized relay to deenergize and stop the motor.
The entire control likely be done by employing a switch, some D-Flip Flops, and a comparator or two...