This paper presents the design of a wireless pressure-monitoring system for harsh-environment applications. Two types of ceramic pressure sensors made with a low-temperature cofired ceramic (LTCC) were considered. The first type is a piezoresistive strain gauge pressure sensor. The second type is a capacitive pressure sensor, which is based on changes of the capacitance values between two electrodes: one electrode is fixed and the other is movable under an applied pressure. The design was primarily focused on low power consumption. Reliable operation in the presence of disturbances, like electromagnetic interference, parasitic capacitances, etc., proved to be contradictory constraints. A piezoresistive ceramic pressure sensor with a high bridge impedance was chosen for use in a wireless pressure-monitoring system and an acceptable solution using energy-harvesting techniques has been achieved. The described solution allows for the integration of a sensor element with an energy harvester that has a printed thick-film battery and complete electronics in a single substrate packaged inside a compact housing.
COBISS.SI-ID: 25475367
Implementation of a novel digital temperature compensation method to the field of capacitive sensors is presented. Possibilities for the compensation of sensor parameters such as sensor nonlinearity and temperature sensitivity are analyzed. In order to achieve effective compensation and linearization, a two-dimensional rational polynomial description and Chisholm approximants were investigated. Evaluation results of sensor response are compared against reference pressure source and most effective digital temperature compensation is proposed.
COBISS.SI-ID: 7814740
This paper presents a solution in which a wireless interface is employed to replace the cables in bridge-sensor measurement applications. The most noticeable feature of the presented approach is the fact that the wireless interface simply replaces the cables without any additional hardware modification to the existing system. In this approach, the concept of reciprocal topology is employed, where the transmitter side acquires signals with its own transfer function and the receiver side reconstructs them with the transfer function reciprocal to the transmitter transfer function. In this paper the principle of data acquisition and reconstruction is described together with the implementation details of the signal transfer from the sensor to the signal-monitoring equipment. The wireless data communication was investigated and proprietary data-reduction methods were developed. The proposed methods and algorithms were implemented using two different wireless technologies. The performance was evaluated with a dedicated data-acquisition system and finally, the test results were analyzed. The two different sets of results indicated the high level of amplitude and the temporal accuracy of the wirelessly transferred sensor signals.
COBISS.SI-ID: 26024231
Implementation of a novel digital temperature compensation method, developed for piezoresistive pressure sensors, to the field of capacitive sensors is presented. Possibilities for the compensation of sensor parameters such as sensor nonlinearity and temperature sensitivity are analyzed. In order to achieve effective compensation and linearization, different approaches to digital descriptions of sensor characteristic are investigated and reported, such as two-dimensional rational polynomial description and Chisholm approximants. Results of sensor response are compared against reference pressure source and most effective digital temperature compensation is proposed.
COBISS.SI-ID: 11768859
A capacitive pressure sensor, fabricated using low-temperature cofired ceramic (LTCC) materials and technology was considered for an application in a wireless sensor system. A sesnsor characterization system with the corresponding software for an evaluation of the sensor’s nonlinearity and temperature sensitivity is presented. The digital temperature compensation was performed with a two-dimensional rational polynominal approximation, resulting in a less than 0,4% FS temperature error in the range 10 to 75°C.
COBISS.SI-ID: 23802151