Abstract: A transmit-receive burglar alarm system provides for code changing so that the user may readily change the transmitted code to which the system will respond. The transmitter is battery powered, and the transmission circuits are disabled except during transmission intervals to conserve battery life, the transmitter transmitting a weak battery signal when the battery voltage falls below a prescribed level, the receiver providing a distinctive signal in response thereto. The transmitter may select one of two channels at the receiver depending upon the desired response and may also select a delayed or immediate response if the receiver is in the delay mode. The home or base station includes a receiver and a microprocessor to determine first if the transmitted code is proper to respond to and then on which of two channels the response is to be indicated; the channels determining the format of the audio signal to be generated both on internal and external audio devices.

Abstract: A portable air compressor which operates from a cigarette lighter socket is housed in a generally triangular casing having a luminescent triangular hazard warning on at least one surface. The casing includes a lower compartment in which the compressor and motor are stored and an upper compartment in which the power cord and air hose are stored. The two compartments are separated by a horizontal wall having a plurality of slots defined therethrough to provide adequate ventilation between the compartments. Flip-up access panels in the sidewalls provide easy access to the top compartment for deployment of the air hose and power cord. Openings in the front and rear walls at the top and bottom of the housing assure ample ingress of air, both to supply the compressor and to establish a convective cooling flow through the compartments and the slotted wall.

Abstract: A keyless vehicle intrusion alarm is armed by momentary depression of the brake pedal or actuation of some other electrically-responsive circuit, followed by the opening and closing of a particular vehicle door within a first predetermined time period. In order to signal the operator that an arming sequence has been initiated, a short burst of the alarm is sounded after the brake pedal or other electric circuit is momentarily activated. Subsequent reentry via that door initiates a time delay during which the entrant must actuate the ignition switch to prevent an alarm from sounding. Entry through any other door, or tampering with the vehicle hood, results in immediate sounding of the alarm. The alarm sounds for a limited time interval before being automatically squelched.