Patent attributes
A personal care appliance with a handle having a coupler at a first end. A control circuit is positioned within the handle. A consumer user interface is operably connected to the control circuit. A digital counter is operably connected to the control circuit. An optical sensor is mounted to the coupler that sends an electrical output signal to the control circuit. A cartridge is removably mounted to the coupler. The cartridge has an opaque surface covering the optical sensor and blocking ambient light from reaching the optical sensor when mounted to the coupler. The control circuit determines an attachment status of the cartridge by comparing the electrical output signal to one or more predetermined thresholds or by detecting a change over time in the electrical output signal of the optical sensor.