A Shear-Threshold Impact Sensor with a Computed Trip Level, Response Time and False-Trigger Behaviour

Threshold sensors fail in two ways: they trip late, or they trip when nothing happened. This paper specifies an impact sensor whose trip level is set by a shear-cap analogue drawn from the density-limit framework, and computes both failure modes. The resonant proof-mass design trips at 63 times standard gravity (620 metres per second squared) with a mechanical response time of 1.41 milliseconds; its thermomechanical acceleration noise is 7.56e-08 metres per second squared per root hertz; and in the rated ambient vibration environment the trip level stands 729 standard deviations above the total noise, so the Gaussian false-trigger estimate falls below any reportable rate. The sensing gap, overrange, and survival ratings are computed from the same parameters. SIMULATED, NOT MEASURED: all figures are computed from the stated assumptions and no device has been built or struck.