1. Basic Anatomy of a Sensor System 8 bit Analog to Digital Converters 8 bit Analog to Digital Converters Share A/D via analog multiplexer Share A/D via analog multiplexer Analog signal conditioning Analog signal conditioning Microprocessor A/D H/L Analog Mux Sensor Control Bus Signal Conditioning

2. 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

3. Switch As easy as on / off, right?...nope signal bounces As easy as on / off, right?...nope signal bounces

4. Switch

5. Temperature MTS102 (available in parts shop) MTS102 (available in parts shop) Linear temp response Linear temp response Use Diff Amp with V2 = 0.637mV, V1 = buffered MTS102 output, R1=1k, R2=40k Use Diff Amp with V2 = 0.637mV, V1 = buffered MTS102 output, R1=1k, R2=40k

6. Bic Infrared Modulate infrared LED at 40kHz Modulate infrared LED at 40kHz LM555 Timer / LC circuit LM555 Timer / LC circuit Columnate LED with Bic Pen Columnate LED with Bic Pen Hack Sharp GP1U58X to obtain analog output reading (may be obsolete) Hack Sharp GP1U58X to obtain analog output reading (may be obsolete) (http://www.mil.ufl.edu/imdl/handouts/sharphack.pdf) (http://www.mil.ufl.edu/imdl/handouts/sharphack.pdf)http://www.mil.ufl.edu/imdl/handouts/sharphack.pdf 1.5V to 2.5V output 100ms Rise time LED 40kHz Modulation Sharp IR Sensor

7. Obtaining Datasheets Manufacturers Home Pages Manufacturers Home Pages Data Bookshelf (http://www.crhc.uiuc.edu/~dburke/databookshelf.html) Data Bookshelf (http://www.crhc.uiuc.edu/~dburke/databookshelf.html)http://www.crhc.uiuc.edu/~dburke/databookshelf.html Links to Manufacturer’s homepages and other resources Links to Manufacturer’s homepages and other resources Datasheet Repositories Datasheet Repositories www.questlink.com www.questlink.com www.questlink.com www.tds-net.com www.tds-net.com www.tds-net.com www.info-quick.com www.info-quick.com www.info-quick.com