Abstract: A toothbrush (10) for applying an electrical stimulus to the gingival region has an electrode (40) on the handle and an electrode (22) having nibs (24) at the base of the bristles (20). Electronic circuitry (28) is housed in the handle (14) for applying a bipolar voltage waveform, which is preferably a square wave of about 50 Hz, across the electrodes (22,40). A device such as an LED or buzzer is provided for indicating when the toothbrush is switched on.

Abstract: An electro-therapeutic device comprises an elongate hand held casing 1 having a tip electrode 4 at one end and an electrode 11 along one side. The tip electrode 4 is placed against the body and a high voltage (40 to 90V) is passed between the electrodes to stimulate the body at low resistance or acupuncture points. In a first aspect of the invention a low voltage DC current passes through the body and changes in the resistance of the body are used to modulate an audible signal to indicate when a low resistance point is reached. In a second aspect the casing 1 is of elongate cross-section so that electrode 11 sits snugly in the web of the hand. In a third aspect of the invention a pulsed, bipolar waveform is applied to the electrodes to avoid electrolytic action in the body. A solid state (transistor/diode) switch is also described for connecting the electrodes across a secondary winding of a transformer during a stimulation mode.

Abstract: A liquid monitoring device includes means for detecting the presence of a liquid and means for giving an alarm when the liquid is detected. Preferably a temperature sensor is also provided and the temperature is displayed on an LCD. The temperature sensor is arranged to sense the ambient air temperature at a first sampling rate and then the liquid temperature, after the liquid has been detected by a detector, at a second, more frequent sampling rate. The components are housed in a casing which carries a pivotably mounted sucker for attachment to a wall or bath.

Abstract: A distance measuring device including a casing bearing a visual display and incorporating therein a transmitter for directing signals toward a selected surface; a receiver for detecting echoes from the selected surface; distance calculating circuitry for measuring the distance to a selected surface in accordance with the transit time of the signal; visually displaying the calculated distance; memory for storing at least two displayed distances measured in perpendicular directions; multiplication circuitry for multiplying the stored measurements; and visually displaying the product of the multiplication. The device further includes a key to effect the operation of the device whereby a distance is displayed, another key to initiate the storage of a displayed distance; and a key to initiate the multiplication of the stored distance measurements.

Abstract: A parallel bus alarm system in which address signals are represented by successive voltage steps, and responses are represented by current increments. Each alarm element, in response to its addressing, controls a variable current increment to flow in the bus, the magnitude of the current increment being a function of an associated analog measurement to be reported. Each alarm element also causes a predetermined current increment to flow in the bus in response to a condition arising which requires reporting, the total current change thus being directly proportional to the number of alarm indications.

Abstract: A single-wire loop alarm system in which an identification module is placed across each alarm switch. Any module which is across an open switch is powered by the loop current and, in response to a pulse count in the loop representing its address, changes the loop impedance in order to report on its status. The loop current may alternate in direction so that oppositely poled modules may be used, thus allowing a larger number of powered modules to accommodated at the same time.

Abstract: A single-wire loop alarm system in which the status of each alarm switch can be determined and which is relatively immune to the effects of noise. False alarms are avoided by incorporating an integrator in the loop potential test circuit; during polling, however, the integrator is switched out. Low-frequency noise is discriminated against by verifying the existence of an alarm condition; the loop current is doubled and, if the alarm condition is being caused by an impedance-introducing open alarm switch, the loop voltage change should double. Polling is made more reliable by relying on a "window" test, rather than a simple threshold test.