text: This invention relates to control circuits and switch apparatuses that can selectively cause a light to either flash on and off or operate continuously, as desired.
  For some time now it has been recognized that being able to cause the porch light of a home to flash on and off can be useful. A flashing porch light can be an indication to neighbors that someone inside is helplessly ill, frightened by prowlers or needs some other emergency assistance. An obvious need for such a flashing light is to help emergency vehicles find a particular address after being summoned by telephone. In urban areas, there are often many houses that look similar and identifiable only by house numbers, which can be difficult to see at night. In rural areas, where roads and houses may not be marked with names or numbers, directions must be given by landmarks alone. It is clear that a flashing outside light would be very helpful in these situations.
  Various approaches to providing both a flashing light and a continuous light from the same bulb are known in the prior art. U.S. Pat. No. 4,177,408 describes a switch apparatus used with existing wiring and light fixtures that derives its flashing action from a thermally-activated flasher disc. U.S. Pat. No. 4,556,863 discloses a switch apparatus used in a similar manner but with an electronic flashing circuit. Both of these inventions, being replacement switch apparatuses, require careful installation into the building's wiring system; a task which is, unfortunately, beyond some homeowners' skills.
  U.S. Pat. No. 4,547,761 describes a special, batterypowered lamp post that can be activated by radio control from inside the house. While this does provide remote control for the light and avoids certain problems with wiring or switch changes, it is obviously a costly solution to the problem at hand.