Abstract: A moisture meter (1) has a capacitive sensing circuit (11-16) feeding into a digital control circuit having a microcontroller (17). Input buttons (20, 22, 23) allow a user to select a material being surveyed. They also allow the user to instruct the meter (1) to hold a particular reading. This allows it to be more conveniently read. The output of the digital control circuit is fed via an ADC (18) to a moving coil meter (4). This provides an easy-to-read display in which trends as the meter (1) is moved across a surface are easy to track.

Abstract: A moisture meter (1) has a hand-held casing (2) with a digital microcontroller (50), LCD display (4), and a keypad (3). Spring-loaded contacts (6) contact material and allow capacitive impedance measurement via electrodes (5) and drive/pickup circuits (20). Also, a relative humidity probe (9) provides an input so that the processor generates both moisture contact near-surface measurements and also relative humidity measurements. This allows optimum analysis of material.

Abstract: A moisture meter (1) has an LCD display (8) driven by a digital microcontroller (50) which generates digital moisture reading data. Readings are stored as discrete records in files. The microcontroller (51) stores a library of material data and automatically compensates signals from a capacitive/impedance sensor circuit (51) according to both stored material parameter values and sensed temperature. Users may edit the parameter values. A non-removable cover (4) is used at the final stage of production to configure the meter for the nature of interfacing (such as serial port interfacing) required.

Abstract: This invention relates to hand-held instruments such as moisture meters (1). An extruded aluminum channel is cut to form a housing blank (2). This blank has inwardly directed ribs (20, 21) which form grooves so that a circuit (22) may be easily slid into the housing, as may a backing plate (27). End caps (5, 14) are secured to the ends of the blank (2) using self-tapping screws (5(a), 5(b)) which engage the ends of ribs (20, 21). The instrument is of extremely rigid construction and does not distort easily and secondly, the method of production is extremely simple and versatile. Versatility is achieved, for example, by the fact that the backing plate may include any different type of sensor and the front of the instrument may be configured according to a label which is secured to the housing blank which may cover apertures which are not needed for switches. Thus, the same housing blank may be used for all instruments and the same manufacturing techniques may also be used.

Abstract: An apparatus for capacitance or dampness measurement is provided. The apparatus is particularly suitable for continuous determination of dampness over substantially flat surfaces such as roofs, floors, pavements and walls. The apparatus essentially includes a pair of substantially elongate electrodes attached to a casing which has a pair of removable surface engaging wheels a handle for pushing and steering, a pair of grip handles for carrying and maneuvering, and two recesses, one for a power supply and the other for an electronic monitoring apparatus combined with a read-out display means. The electrodes are separated by a gap of approximately 5 cm and are retained on the casing so as not to be taut but to be slightly floppy so as to permit good contact between the electrodes and the surface to be tested. The value of capacitance/unit area of the electrodes in air is preferably in the range 50 pFm.sup.-2 -150 pFm.sup.-2.