sensing and sensors 16-722 - S2004 F 9a30-12p20 NSH1305

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sensing and sensors16-722 - S2004 F 9a30-12p20
NSH1305

• Jen Morris ltjenmorris_at_cmu.edugt
• 1 412 268 3303
• office HH A313

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L2004-10A

• Solid-state Chemical Sensors and Chemical Sensor
  Arrays

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Bibliography

• Figaro Engineering, Inc.
• http//www.figarosensor.com/
• MicroChemical Systems SA
• http//www.microchemical.com/
• http//www.sensors.com.cn/download/MiCS/
• Cyrano Sciences, Inc.
• http//cyranosciences.com/

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Solid-State Chemical Sensors

• Metal-oxide semiconductor layer
• Usually tin dioxide (SnO2)
• Apply heat
• In air
• Surface oxygen increases (negatively charged)
• Resistance increases
• In presence of deoxidizing gas
• Surface oxygen decreases
• Resistance decreases

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How They Work
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Figaro Engineering, Inc.

• Chemical gas sensors
• LP-Gas/Propane (500-10000ppm)
• Natural gas/Methane (500-10000ppm)
• General combustible gas (500-10000ppm)
• Hydrogen (50-1000ppm)
• Carbon monoxide (50-1000ppm)
• Ammonia (30-300ppm)
• Hydrogen sulfide (5-100ppm)

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Figaro TGS 2442

• Carbon Monoxide Sensor
• Applications
• CO detectors
• Air quality controllers
• Indoor parking lot ventilation
• Gas sensing layer
• Tin dioxide (SnO2)

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Figaro TGS 2442

• Features
• Low power consumption
• High sensitivity/selectivity to carbon monoxide
  (CO)
• Miniature size
• Low sensitivity to alcohol vapor
• Long life and low cost
• Low humidity dependency

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TGS 2442 Basic Measuring Circuit

• 1 second heating cycle
• 1 second circuit voltage cycle

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TGS 2442 Specifications
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SnO2 for CO Sensing

• Rs Sensor resistance of displayed gases
• Ro Sensor resistance in 100ppm CO

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SnO2 for CO Sensing

• Rs Sensor resistance at 30ppm, 100ppm and
  300ppm
• of CO at various temperatures and 50R.H.
• Ro Sensor resistance at 300ppm of CO at 25C
  and 50 R.H.

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MicroChemical Systems SA

• Chemical gas sensors
• Ozone (0.01-10ppm)
• Nitrogen Dioxide (0.05-5ppm)
• Ethanol (50-1000ppm)
• CO / NO2 (1-400ppm/0.05-5ppm)
• Carbon Monoxide HCs (1-400ppm)

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MicroChemical Systems MiCS-3110

• Ethanol Sensor
• Applications
• Breathalizer (Blood Alcohol Content)
• Various industrial applications
• Gas sensing layer
• Tin dioxide (SnO2)

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MicroChemical Systems MiCS-3110

• Features
• Low heater current
• Wide detection range
• High sensitivity
• Fast thermal response
• Electro-Static Discharge protected
• Miniature dimensions
• High resistance to shocks and vibrations

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MiCS-3110 Basic Measuring Circuit

• Run in constant voltage mode
• Heater voltage of VH 2.4 V
• increases temperature of Rs to 430C

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MiCS-3110 Specifications
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SnO2 for Ethanol Sensing

• RS Sensor resistance to C2H5OH
• R10ppm Sensor resistance resistance in 10 ppm
  of C2H5OH

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Chemical Sensor Arrays

• Array of polymer composite sensors
• Swell in presence of vaporized analyte
• Conductive polymer pathways broken
• Resistance increases
• Different gases produce different responses

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Cyrano Sciences, Inc. Cyranose 320

• Hand-held chemical vapor sensor
• 32 thin-film carbon-black chemiresistors
• Trained by taking different measurements
• Create a database of patterns
• Match odors against saved patterns

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Cyranose 320 Specifications
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Cyrano Sciences, Inc. NoseChipTM

• Under development
• Low cost, low power, lightweight sensing
• Optional short-range wireless capability
• Applications
• Sensing nodes for facilities protection
• Personal badge detectors for toxic industrial
  chemicals and chemical warfare agents
• Residual life indication
• Leak detectors in military or commercial systems
• Quality monitors in embedded systems

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NoseChipTM Specifications
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Bibliography

• Figaro Engineering, Inc.
• http//www.figarosensor.com/
• MicroChemical Systems SA
• http//www.microchemical.com/
• http//www.sensors.com.cn/download/MiCS/
• Cyrano Sciences, Inc.
• http//cyranosciences.com/