Abstract: A device and method are described for measuring the weight of objects using a pneumatically sealed bellows which contains a pair of spaced apart capacitor plates. In accordance with the invention, the pneumatic pressure within the bellows is varied to maintain constant dimensions for the bellows and a constant distance between the electric capacitor plates. This pressure is therefore a function of the weight placed upon the bellows which exerts a pressure tending to force the walls of the bellows and the capacitor plates closer together thereby changing the electric capacitance between the capacitor plates. By adjusting the pneumatic pressure to maintain a constant electric capacitance and constant dimensions for the bellows, a convenient parameter is obtained from which the weight of objects placed on the bellows can be measured. The invention has particular application in the meteorological sciences.

Abstract: An improved soil moisture sensor and circuity are described which permit a more compact, simplified, and less expensive integrated unit wherein the essential circuitry of the device is sealed within the sensor head. Determinations of resistance and capacitance are made using a coaxial or other capacitor having spikes or probes which are inserted into the soil or other material.