Sensors: Materials and Applications
General objectives: To make available to the students the concepts that is at the origin, development and manufacture of sensors as well as the properties of materials used in their manufacture. To introduce the students to the technologies associated with the measures of physical and chemical properties in an industrial environment or in laboratory.
Specific objectives: To understand the physical principles used in transducers and sensors, their characteristics and materials used in its construction, linking this to the specific study of measurements of the main physical quantities: temperature, force, pressure, displacement, strain, etc. .. Understand the operation and materials used in chemical sensors to detect volatile organic compounds.
Study the most appropriate signal conditioning for each type of sensor. Develop practical skills in using sensors and setups for the different studied sensors.
Rui Alberto Garção Barreira do Nascimento Igreja
Weekly - 5
Total - 66
To general knowladge in the areas of physics, chemistry, material science and circuit theory.
Slides used in the course available through the CLIP
Instrumentation for Engeneering Measurements, James Dally, Wiley.
Les Capteurs en Instrumentation Industrielle, Georges Asch, Dunod.
Measurement Systems Applications and Design, Ernest O. Doebelin, McGraw-Hill.
Instrumentação Industrial, Gustavo da Silva, Escola Superior de Tecnologia de Setúbal.
AIP Handbook of Modern Sensors, Jacob Fraden, AIP Series in Modern Instrumentation.
The Measurement, Instrumentation and Sensors Handbook, ed John g Webster, IEEE Press.
Sensors Update - Wiley – VCH. Journals: Sensors and Actuators A and B, Elsevier. Sensors (IEEE).
Theoretical classes with datashow. Problem solving classes with student participation.
Practicals include theory preparation, experimental procedure and production of a small report.
A short project will be developed in practical classes
evaluation of a theorethical work (NTP): 2 tests (NTP= tets average)
evaluation of a pratical work (NP): with 2 reports P1 (10%) and TP2 (10%) +small (80%)
summative evaluation NS (presence in TP classes)
Final grade without exame: NAC=0,4*NTP+0,55*NP+0,05*NS
Final grade with exame: NAC=0,45*NTP+0,55*NP
1. Sensors and signals. Brief Introduction to Metrology. Physical principes of measurement and materials properties.
2. Temperature sensors - Resistance temperature sensors (RTDs). Methods for resistance measurements; poteniometer circuit; Wheatstone bridge. Sensibility and nonlinearity of the Wheatstone bridge (constant voltage and constant current). The thermistor. The problem of self-heating on temperature measurements. Thermocouples; properties and materials for thermocouple construction; measurement methods; cold junction compensation. Temperature measurements with semiconductors and integrated circuits. Radiant sensors; pyroelectric detectors; pyroelectric effect; methods and materials; pyrometers. Dynamic response of temperature sensors.
3. Strain and stress sensors - Resistance-type strain gages. Materials for strain gages. Etched-foil strain gages; instalation; the wheatstone bridge for strain gage signal conditioning; calibration methods; Effects of lead wires, switches and slip rings; electrical noise; temperature compensated strain gages; cross sensitivity factor; modulation and syncronos demodulation for strain gages signal conditioning. The stress gage. Methods for evaluation of principal stresses on a general state of stress using strain gages. Linear variable diferential transformer (LVDT).
4. Force, torque and pressure measurements - Load cells; link-type load cell; beam-type load cell; ring-type load cell. Torque measurements; torque cells. Pressure measurements; displacement-type ; diaphragm-type; piezoelectric-type.
5. Displacement, velocity, and accelaration measurements - Optical measurements methods; LVDT; Seismic transducers. Accelerometer; piezoelectric-type accelerometers; piezoelectric sensor circuits; charge amplifier for piezoelectric sensors. Measurement of transient signals.
6. Fluid flow measurements - insertion-type transducers; pitot tube; Hot-wire and hot-film anenometers (constant current and constant temperature). Drag-force velocity transducers. Venturi meters.
7. Chemical Sensors and multisensors systems - Transducers for chemical sensing; capacitive; cristal quartz microbalance; figaro type sensors. Sensitive layer materials. Adsorption and absortion of organic volatile molecules on sensitive layers. Methods for choosing polymer sensitive layers. Multisensor systems; methods for signal treatment on multisensor systems; methods for data reduction and data evaluation in multisensor systems (principal component analysis; linear discriminant analysis and neural networks).