Basic Anatomy of a Sensor System Sensor Signal
Basic Anatomy of a Sensor System Sensor Signal Conditioning A/D Analog Mux A/D H/L Control Bus l l l 8 bit Analog to Digital Converters Share A/D via analog multiplexer Analog signal conditioning Microprocessor
Sensing Challenges Challenge Potential Approaches Inadequate voltage / current Op Amp, buffer, transistors Noise Low Pass Filter Bouncing S/R Latch Capture Signal Sample & Hold Limited Sampling Rate New sensor 8 bit A/D limited to 256 levels Vary op-amp gain by switching in resistors with an analog mux
Switch l As easy as on / off, right? . . . nope signal bounces
Switch
Temperature l MTS 102 (available in parts shop) l l Linear temp response Use Diff Amp with V 2 = 0. 637 m. V, V 1 = buffered MTS 102 output, R 1=1 k, R 2=40 k
Infrared l Modulate infrared LED at 40 k. Hz l l l LM 555 Timer / LC circuit Columnate LED with Bic Pen Hack Sharp GP 1 U 58 X to obtain analog output reading (may be obsolete) l (http: //www. mil. ufl. edu/imdl/handouts/sharphack. pdf) LED 40 k. Hz Modulation Bic Sharp IR Sensor 1. 5 V to 2. 5 V output 100 ms Rise time
Obtaining Datasheets Manufacturers Home Pages l Data Bookshelf l (http: //www. crhc. uiuc. edu/~dburke/databookshelf. html) l l Links to Manufacturer’s homepages and other resources Datasheet Repositories l www. questlink. com l www. tds-net. com l www. info-quick. com
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