Abstract: An alarm activator in the form of a ring-transmitter can be squeezed readily to activate an alarm by either ultrasonic or radio or infrared waves. The ring consists of either an ultrasonic or radio or infrared transmitter in a casing welded on an incomplete ring. Inside the casing is located a power source, a time delay circuit, an oscillator, a timer and either an ultrasonic or radio or infrared transducer. The tips of the incomplete ring are provided with two conductors, e.g. silver plates, one on each tip, forming a normally open contact. An all-around clearance is provided between the casing and the ring to permit the compression of the ring without interference from the casing to close the normally open contact and to permit current to flow from the power source through the time delay, energizing the timer which in turn will turn on the oscillator for a short time.