The ornamental design for a humiditysensor, as shown and described.
2. Humidity sensor
2.1 : Perspective
2.2 : Top
2.3 : Cross-section view taken along line 2.3-2.3 in Fig. 2.2
2.4 : Cross-section view taken along line 2.4-2.4 in Fig. 2.2.
In the drawings, the broken lines represent portions of the humidity sensor that form no part of the claimed design; all sides not disclosed in the drawings form no part of the claimed design.