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Do you have a question on MEMS Sensors? Ask our Expert, Donna Sandfox

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Donna Sandfox

Donna Sandfox is the Product Manager for Sensors and MEMS Products for Omron Electronic Components LLC.  Her primary area of expertise is in MEMS Mass Flow Sensors.  She also supports Omron’s pressure, thermal IR, tilt/vibration and optical (photomicrosensors) sensors, as well as their RF MEMS Switch products.  Donna received her bachelor’s degree in mechanical engineering from Southern Illinois University and an MBA from Roosevelt University.


 


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  • Hi Donna,

     

    Welcome to Element14.

    I know I've been lazy in not researching this myself, but could you explain why the MEMS approach is considered better than existing sensor technology?

    Everyone is talking like its the next best thing since the IPAD, so I am curious where the hype is coming from and what the true merits to the technology might be.

     

    Thanks,

    DAB

  • in reply to DAB

    Hi Don!

    Thank you, and thanks for the question.  While volumes can be written comparing and contrasting all of the different technologies available for measuring gas flow, I'll try to give a reasonably brief answer by limiting it to non-MEMS thermally based mass flow measurement.

     

    MEMS mass flow sensors are constructed of two sets of thermopiles with a heater between them.  Each thermopile set is comprised of several very small (obviously) thermocouples connected in series.  This design makes the MEMS mass flow chip very sensitive compared to a single set of thermocouples (< 1cm/sec can be measured).  The MEMS chip also has a very fast response time (<5 msec) and low power consumption.

     

    Omron's MEMS chip employs deep top-etching and dielectric thin layer deposition manufacturing techniques resulting in a high surface area to volume ratio, further improving sensitivity. 

     

    Sometimes seeing is easier than reading; if you'd like to see some graphical representation of what I've described above we have a Product Training Module on our website at:  http://www.components.omron.com/components/web/webfiles.nsf/PTM.html.

     

    One final note, when constructing a flow sensor... The MEMS chip (or other basic measurement technology) is important, but also are the supporting circuitry (for signal processing and temperature compensation) and the physical design of the flow path (a solid understanding of fluid dynamics is required to ensure good flow characteristics for accurate measurement results).

     

    Hope this was helpful!

Reply
  • in reply to DAB

    Hi Don!

    Thank you, and thanks for the question.  While volumes can be written comparing and contrasting all of the different technologies available for measuring gas flow, I'll try to give a reasonably brief answer by limiting it to non-MEMS thermally based mass flow measurement.

     

    MEMS mass flow sensors are constructed of two sets of thermopiles with a heater between them.  Each thermopile set is comprised of several very small (obviously) thermocouples connected in series.  This design makes the MEMS mass flow chip very sensitive compared to a single set of thermocouples (< 1cm/sec can be measured).  The MEMS chip also has a very fast response time (<5 msec) and low power consumption.

     

    Omron's MEMS chip employs deep top-etching and dielectric thin layer deposition manufacturing techniques resulting in a high surface area to volume ratio, further improving sensitivity. 

     

    Sometimes seeing is easier than reading; if you'd like to see some graphical representation of what I've described above we have a Product Training Module on our website at:  http://www.components.omron.com/components/web/webfiles.nsf/PTM.html.

     

    One final note, when constructing a flow sensor... The MEMS chip (or other basic measurement technology) is important, but also are the supporting circuitry (for signal processing and temperature compensation) and the physical design of the flow path (a solid understanding of fluid dynamics is required to ensure good flow characteristics for accurate measurement results).

     

    Hope this was helpful!

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