We claim the ornamental design for a danger signal generator, as shown and described.
FIG. 1 is a front perspective view of a danger signal generator showing our new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a left-side view thereof;
FIG. 5 is a right-side view thereof;
FIG. 6 is a top view thereof;
FIG. 7 is a bottom view thereof;
FIG. 8 is a rear perspective view thereof;
FIG. 9 is a front perspective view of the danger signal generator in which a bracket is provided in broken lines to illustrate an example environment; and,
FIG. 10 is another front perspective view of the danger signal generator in which a bracket is provided in broken lines to illustrate an example environment.
In the drawings, the broken lines depict environmental subiect matter that forms no part of the claimed design.