Described is an animal waste product notification device for detecting the occurrence of an animal excreting animal waste product at a defined location, containing the waste product such that the animal cannot track the waste product from the defined location, and notifying a local or remote individual of the occurrence. A rear trunk is mounted on a rear portion of a body of the vehicle, a lid having a projection formed outside on top of the trunk, and a radio signal receiving unit is disposed inside the projection. The illustrative embodiment is velocity-cooled when the elastic mean-free path of the electrons is greater than the channel length, L, of the mixerdetector.