Abstract: Dispensing machines are described which are suitable for use in a cold environment. The machines have a plurality of storage locations for supporting articles to be dispensed, each of which includes an electrical heating element. The heating elements can be energized individually and the heat generated by an energized heating element causes an article supported at the respective storage location to be released.

Abstract: Machine for automatic rental of video cassettes. Cassettes are stored in a drum like magazine (32) and are made available at a dispensing slot (20, 22) after a user has identified himself by introducing a personal into a slot (12) and entered a unique personal code number on a keyboard (16) which the user also employs to enter the selection from the available video cassettes. On returning the cassette, the user again identifies himself and the machine verifies by reading a bar code that the hired film has been returned.

Abstract: A presence sensing system comprises a detector having a transmitter for transmitting an interrogation signal to an area to be kept under surveillance and a receiver for receiving a presence indicating signal. A receiver/transmitter device the presence of which is to be detected is adapted to receive the interrogation frequency and to transmit a presence indicating signal in response thereto. A phase locked loop circuit has a first input coupled with the output of the receiver a second input for a reference signal, and an output for providing a phase locked signal which is indicative of phase coherence between the signals on the two inputs. A frequency generator has an output coupled with the second input of the phase lock loop and an alarm is actuable in response to the phase locked signal.The invention also includes the presence sensing detector described in the above system.