Tech Briefs Magazine - September 2021 - 39

Solid-State Carbon Dioxide Sensor
Applications include wearables, airplane cabin monitoring,
medical diagnostics, and indoor air quality measurement.
Ames Research Center, Moffett Field, California
D
etection of carbon dioxide (CO2) is
very important for environmental,
health, safety, and space applications.
Carbon dioxide is a harmful pollutant at
higher concentrations due to its ability to
displace oxygen in large concentrations.
Current commercial sensors for CO2
have issues and shortcomings, particularly
with precision at different temperatures,
pressures, and high humidity levels.
NASA Ames has developed a patentpending
solid-state sensor configured
for detection of CO2 having a concentration
within the range of about 100 parts
per million (ppm) and 10,000 ppm in
both dry conditions and high-humidity
conditions.
The solid-state sensor achieves detection
of high concentrations of CO2 without
saturation and in both dynamic flow
mode and static diffusion mode conditions.
The composite sensing material
comprises oxidized multi-walled carbon
nanotubes (O-MWCNT) and a metal ox -
ide; for example, O-MWCNT and iron
oxide (Fe2O3) nanoparticles. The composite
sensing material has an inherent
resistance and corresponding conductivity
that is chemically modulated as the
level of CO2 increases.
The CO2 gas molecules absorbed into
the carbon nanotube composites cause
charge-transfer and changes in the conductive
pathway such that the conductivity
of the composite sensing material is
changed. This change in conductivity
provides a sensor response for the CO2
detection. The sensor is well suited for
automated manufacturing using robotics
and software-controlled operations.
The sensor does not utilize consumable
components or materials and does
not require calibration as often as conventional
CO2 sensors. Since the technology
can be easily integrated into ex -
isting programmable electronic systems
or hardware systems, the calibration of
the sensor can be automated. The sensor
can be easily integrated into existing
electronic circuitry and hardware configurations
including the hardware of a
mobile computing device such as a
smartphone or tablet device.
NASA is actively seeking licensees to commercialize
this technology. Please contact
NASA's Licensing Concierge at Agency-PatentLicensing@mail.nasa.gov
or call us at 202358-7432
to
initiate licensing discussions.
Follow this link for more information: https://
technology.nasa.gov/patent/TOP2-292.
HIGH-PRECISION
HIGH-PRECISION
capaNCDT 61x0/IP
capaNCDT 61x0/IP
CAPACITIVE
MEASUREMENT SYSTEM
CAPACITIVE
MEASUREMENT SYSTEM
 Unmatched accuracy and stability
 Temperature range -270 °C to +200 °C
 High interference immunity against
 magnetic fields
magnetic fields
Unmatched accuracy and stability
Temperature range -270 °C to +200 °C
High interference immunity against
 Customer-specific designs for OEM and
serial integration
 Customer-specific designs for OEM and
serial integration
 Ideal for industrial measurement tasks
 Ideal for industrial measurement tasks
EDDY-CURRENT SENSORS
NON-CONTACT
EDDY-CURRENT SENSORS
NON-CONTACT
 Nanometer resolution
 Custom OEM design
 Robust sensors for extreme environments,
 e.g. high temperature, vacuum ...
Nanometer resolution
Custom OEM design
 Sensors with Embedded Coil
Technology (ECT)
 Sensors with Embedded Coil
Technology (ECT)
Robust sensors for extreme environments,
e.g. high temperature, vacuum ...
easuring ranges fr m 0.4 to 80 mm
More than 400 sensor models
 Measuring ranges from 0.4 to 80 mm
 More than 400 sensor models
The solid-state CO2 sensor can be easily integrated into existing programmable electronic systems
or hardware systems.
Contact our application engineers:
Phone +1/919 787 9707
micro-epsilon.com
Tech Briefs, September 2021
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ToC
Contact our application engineers:
Phone +1/919 787 9707
micro-epsilon.com
Free Info at http://info.hotims.com/79417-756
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Tech Briefs Magazine - September 2021

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