use hot glue to glue to popsicle sticks to the bottom of an altoids tin. Make sure a 9 volt battery can fit in it. You might need something to hold the battery in place.
then cut a hole in the bottom of the tin. Then put a hobby engine in the hole with the point pointing down. Make sure when the battery touches it ti starts spinning. Then glue it in place. Then glue toothbrush heads to the bottom of the tin.