| 摘要 |
<p>A radio-signal-based mail delivery alarm system comprising a transmitter unit provided in connection with a mailbox or mail-slot flap (2) and a receiver unit for being located at a distance from the transmitter unit and being able to receive a radio signal emitted by the transmitter unit. The transmitter unit comprises a movement sensor for detecting movement of the mailbox or mail-slot flap (2) and a transmitter with power supply and antenna (12) for emitting a radio signal in response to movement of the mailbox or mail-slot flap (2). As opposed to the prior art transmitter units for such mail delivery alarm systems, the present transmitter unit is built integrally with the mailbox or mail-slot flap (2).</p> |
