The ornamental design for a miniprojector, as shown and described.
FIG. 1 is a front right side top perspective view of the mini projector showing my new design;
FIG. 2 is a rear left side bottom perspective view thereof;
FIG. 3 is a front elevational view thereof;
FIG. 4 is a rear elevational view thereof;
FIG. 5 is a left side elevational view thereof;
FIG. 6 is a right side elevational view thereof.
FIG. 7 is a top plan view thereof; and,
FIG. 8 is a bottom plan view thereof.
The broken line showing in the drawings is included for the purpose of illustrating portions of the mini projector and forms no part of the claimed design.