An impact sensor includes a piezoelectric transducer operatively connected to a chromic device. The chromic device includes a chromic material that changes from a first color state to a second color state in response to electric power generated by the piezoelectric transducer when exposed to a given level of impact force. The chromic material is bistable so that the chromic material remains in the second color state for a significant amount of time. An impact force to which the sensor has been subjected may be quantified by observing the chromic device. In one embodiment, the chromic material is an electrochromic material, such as a viologen, that changes through a color gradient of light transmission states from the first color state to the second color state. A printed color gradient may be used to aid in quantifying the impact force. In another embodiment, the chromic device includes a thermochromic material.