FIG. 1 is a perspective view of a sensor for measuring indoor environment showing the new design: FIG. 2 is a front perspective view thereof; FIG. 3 is a rear view thereof; FIG. 4 is a left-side elevation view thereof; FIG. 5 is a right-side elevation view thereof; FIG. 6 is a top plan view thereof; and, FIG. 7 is a bottom plan view thereof.