FIG. 1 is a perspective view showing the ornamental design of a sensor in accordance with the present invention;
FIG. 2 is a side view showing the ornamental design of a sensor in accordance with the present invention;
FIG. 3 is a bottom perspective view showing the ornamental design of a sensor in accordance with the present invention;
FIG. 4 is a perspective view showing an embodiment of the present invention with dashed lines illustrating an environment of use;
FIG. 5 is a side view of the embodiment of FIG. 4; and,
FIG. 6 is a lower perspective view of the embodiment of FIG. 4.