Patents by Inventor Noel Calvin

Noel Calvin has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Automatic doorbell
    Patent number: 4236147
    Abstract: Microwave transmitting means, receiving means, and detector means such that the change in the standing wave pattern surrounding said transmitting means caused by the approach of a person on one side of said transmitting means can be detected and distinguished from the approach of a person on the other side, and tone generator means such that an audible tone is generated when a person approaches from one side, but not when a person approaches from the other, adaptable for use as an automatic doorbell.
    Type: Grant
    Filed: December 9, 1977
    Date of Patent: November 25, 1980
    Inventor: Noel Calvin