Patent ID: 7187936

Claim:
A radio frequency receiving device comprising: an electronic circuitry including a microprocessor, a memory unit, a button, an LED, a speaker device, and a radio frequency receiver circuitry; the memory unit comprised of a DRAM, the DRAM for storing an instruction to direct an action of the microprocessor; the button depressible to manually activate an input circuitry, the input circuitry for sending input signals to the microprocessor; the microprocessor having an output circuitry; the LED for displaying an output display signal from the output circuitry; the electronic circuitry having an internal state, the internal state including a sleep mode, an active mode and an alarm mode; the radio frequency receiver circuitry for receiving a radio frequency signal from a radio frequency transmitter; the radio frequency receiver circuitry for sensing and determining if the radio frequency signal has a compatible characteristic of an expected signal; the radio frequency receiver circuitry for converting the radio frequency signal into a digital form; the radio frequency receiver circuitry for sending the digital form to the microprocessor a counter maintained by the microprocessor, the counter for tracking a cumulative number of the digital form of the radio frequency signals received by the radio frequency receiver circuitry; an incremental advancement of the counter by the microprocessor; a check by the microprocessor of the counter to determine if the counter is above an upper count limit of the counter, the upper count limit fixed and pre-determined for the radio frequency receiving device; and the alarm mode entered into by the microprocessor, if the microprocessor determines in the check of the counter that the counter above the upper count limit.