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Micro-sensors |
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Accelerometer:
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Device design has sensing method of strain gauge type. This is as shown below. Design calculations involved in these are, Finding dimensions and stresses by FEM (finite element method) analysis, Finding frequencies by Modal FEM, the consideration for thermal expansion and damping can be done by FEM and experimental verification. |
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Figure 31.8 Accelerometer |
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Sensing Methods : |
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Resistive sensing |
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Based on strain: accelerometers where resistance changes with strain |
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Based on temperature: where resistance changes with temperature |
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Capacitive sensing: accelerometers, pressure sensors |
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Bimetallic strips : which has strains as per the temperature changes |
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Thermocouple effect: This has voltage developed as per temperature effect. |
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Piezoelectric effect : This has charge developed as per strains in piezo |
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Using optics laser source and detectors |
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Diffraction effects: where the light diverges into wider angle |
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Interference effects : where the interference occurs with other waves. |
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Quadrature photo diodes: where the photodiodes output is fed to quadrature decoding arrangement. |
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More MEMS devices |
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Other micro-sensors: |
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Pressure sensor |
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Vibrating gyroscope |
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Bio-MEMS sensors: DNA chips, “lab on chip” |
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Micro actuators |
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Comb actuators, micro-motors |
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Thermal actuators |
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Piezo-actuators |
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Micro-gears, micro-engines |
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Micro-fluidic systems: Inkjet printers, drug delivery |
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Grating light valve (GLV display) |
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Digital optical switches |
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And many more Yet to come… |
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