Tech Briefs

MEMS to Replace Quartz Oscillators as Frequency Sources

A new encapsulation and packaging technology for MEMS resonators provides a clean, stable environment for reference oscillators. Research on microelectromechanical system (MEMS) resonators dates back to the mid-1960s, but MEMS timing references are only now being introduced commercially. In this time, two fundamental technical challenges have been overcome: finding a stable and predictable material from which to build the resonators, and developing a sufficiently clean hermetic packaging system.

Posted in: Briefs, Electronics & Computers

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“Virtual Feel” Capaciflectors

Increases in capacitance with deviations from desired central positions would be exploited. The term “virtual feel” denotes a type of capaciflector (an advanced capacitive proximity sensor) and a methodology for designing and using a sensor of this type to guide a robot in manipulating a tool (e.g., a wrench socket) into alignment with a mating fastener (e.g., a bolt head) or other electrically conductive object. Unlike robotic vision, capacitive proximity sensing does not require a clear line of sight to the mating fastener. On the contrary, capacitive proximity sensing affords the greatest position-measuring sensitivity in the situation in which it is most needed — when the tool is so close to the fastener as to prevent viewing.

Posted in: Briefs, Electronics & Computers

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Magnetic-Field-Response Measurement-Acquisition System

Sensors are interrogated without physical connection to a power source, microprocessor, data acquisition equipment, or electrical circuitry. A measurement- acquisition system uses magnetic fields to power sensors and to acquire measurements from sensors. The system alleviates many shortcomings of traditional measurement acquisition systems, which include a finite number of measurement channels, weight penalty associated with wires, use limited to a single type of measurement, wire degradation due to wear or chemical decay, and the logistics needed to add new sensors. Eliminating wiring for acquiring measurements can alleviate potential hazards associated with wires, such as damaged wires becoming ignition sources due to arcing.

Posted in: Briefs, Electronics & Computers

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Miniature Housings for Electronics With Standard Interfaces

be secured to a mating carrier by use of screws or epoxy; this mounting scheme helps the housings and their contents to withstand severe vibrations and ensures thermal conduction for dissipation of heat generated during operation of the contained circuitry. The circuits contained in the housings communicate with the external world via standard RS-485 interfaces. Multiple units comprising housings and their contents can easily be electrically connected together in a daisy chain arrangement, within which individual units are addressable via the RS-485 bus. Hence, a single master computer connected to the bus can program, or read data from, any or all such units. Examples of such units include small motor drives, programmable thermostats, data loggers, and programmable controllers. There are numerous potential uses for these units in medical equipment, automotive electronics, manufacturing equipment, and robots.

Posted in: Briefs, Electronics & Computers

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Measuring Vapors To Monitor the State of Cure of a Resin

Excess curing time would no longer be needed as margin against uncertainty. A proposed noninvasive method of monitoring the cure path and the state of cure of an epoxy or other resin involves measurement of the concentration(s) of one or more compound(s) in the vaporous effluent emitted during the curing process. The method is based on the following general ideas:

Posted in: Briefs, TSP, Manufacturing & Prototyping

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Templates for Fabricating Nanowire/Nanoconduit-Based Devices

Prior templating processes are being extended to finer spatial resolutions. An effort is underway to develop processes for making templates that could be used as deposition molds and etching masks in the fabrication of devices containing arrays of nanowires and/or nanoconduits. Examples of such devices include thermoelectric devices, nerve guidance scaffolds for nerve repair, photonic-band-gap devices, filters for trapping microscopic particles suspended in liquids, microfluidic devices, and size-selective chemical sensors. The technology is an extension of previous work conducted by JPL, UCSD (University of California, San Diego), and Paradigm Optics Inc., which developed a process to fabricate macroporous scaffolds for spinal-cord repair.

Posted in: Briefs, TSP, Manufacturing & Prototyping

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Reducing Centroid Error Through Model-Based Noise Reduction

Corrections are made for bias and noise.A method of processing the digitized output of a charge-coupled device (CCD) image detector has been devised to enable reduction of the error in computed centroid of the image of a point source of light. The method involves model-based estimation of, and correction for, the contributions of bias and noise to the image data. The method could be used to advantage in any of a variety of applications in which there are requirements for measuring precise locations of, and/or precisely aiming optical instruments toward, point light sources.

Posted in: Briefs, TSP, Information Sciences

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