Abstract: A vehicle anti-theft alarm system comprises a microwave transmitter and receiver for transmitting microwave frequency signals from one location in the vehicle against a target in the vehicle at a given distance from the transmitter-receiver and for receiving the signals reflected back from the target and producing a monitoring signal representative of a time, frequency or distance parameter for sending and receiving the signals. If, for example, an object is interposed in the path of the transmitted signals, the parameter and thus the monitoring signal changes and a control signal is produced for actuating an alarm. A holding circuit provides for the alarm to remain actuated when the article is removed from the path of the transmitted signals.

Abstract: A vehicle anti-theft device in the form of a vehicle steering wheel lock comprising extendable and retractable members having hooks that are on for engaging diametrically opposed portions of a steering wheel to mount the anti-theft device on the steering wheel. It is provided with a motor operated lock mechinism remotely controlled by a personal identification encoder. The lock mechinism also includes a key operated portion, and the lock mechinism is operable either through the use of a key or through the use of the remotely controlled encoder.