▎ 摘　　要

NOVELTY - A piezoelectric signal detecting device comprises two layers of protective layers arranged oppositely comprising at least two layers of sensory layers and insulating layers. The sensory layer is arranged between the two protective layers, and a layer of the insulating layer is arranged between two adjacent layers of the sensory layers. Each layer of the sensory layer comprises a set of sensing units for converting the external stimulus into electric signal. A set of the sensing units are distributed in array, and each row or each column of the sensing unit is connected in series. One end of each row or each column of the sensing unit is grounded. The other end is used for outputting an electric signal. The adjacent two layers of the sensing unit on the sensing layer in the series direction has a calibration included angle. USE - Piezoelectric signal detecting device. ADVANTAGE - The device improves the detection ability of external stimulation. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for: 1. an external stimulus detection method based on the piezoelectric signal detection device; 2. an insole; 3. a classifier training method based on the insole; 4. method for training a classifier; and 5. a gait recognition method DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of a piezoelectric signal detection device. (Drawing includes non-English language text).