bullet Sensors & Transducers e-Digest (S&T)



No. 11, November 2001



Table of Contents

(click article or product title for full pages description)




Investigation of Mechanical Resonators with the Help of Fiber Optic Fabry-Perot Interferometer


Abstract: In this work we described the application of the fiber optic Fabry-Perot interferometer for the measurement of the mechanical resonators' parameters. The electro-magnetic sound generator played a role of the resonator in our experiments. The oscillation of the cone was excited by the alternating current applied to the coil of the sound generator. The same technique can be applied for investigation of different micromechanical resonant structures made of quartz, piezoceramic, or silicon. The sensitivity of the interferrometric interrogation system proved to be enough for the working with the amplitude of oscillation as small as parts of nanometer.


Alexander Churenkov, 

Siltec Ltd., 

Tel/Fax: (7-095) 408-6672 

E-mail: avc.mipt@g23.relcom.ru



Experimental setup
The Ball 3-axis accelerometer


Abstract: Ball Semiconductor Inc. (Allen, TX, Akira Ishikawa, Chairman, President & CEO) has announced that the Company has successfully developed the Ball 3-axis accelerometer and is ready to receive orders for its evaluation board kit starting November 2001.The Ball 3-axis accelerometer device consists of a 1-millimeter spherical silicon as an inner core and a ceramic-based outer shell with the electrical circuits printed onto the inner surface of the shell. There is a gap of several micrometers between the two where an inner core ball is levitated. This accelerometer is processed by a surface micro-machining technology.  There are 6 pairs (12 leaves) of electrodes corresponding to the three axes in the inner wall of the shell. The electrodes are fabricated by a spherical semiconductor device manufacturing technology, including a spherical photolithography technology.


Hideshi Nakano,

Executive Vice President and COO

Ball Semiconductor Inc., 415 Century Parkway, Allen, Texas 75013 USA

Phone: 972-359-2422

e-mail: hnakano@ballsemi.com

3-axis accelerometer





Customiseable Endless Rotary Sensor/Potentiometer


Here is Piher's "revolutionary" answer to the majority of Multi-Purpose Control and Rotary Sensor design problems which were un-resolveable until now. The N-15 series offers you full endless rotation, 340є 10є wide electrical angle, SMD or through-hole mount, extended working temperature range of -40єC to +120єC plus a whole series of customisation possibilities making it the most flexible product on the market. The N15 is ideal for Appliance and Automotive Control and Sensor applications.


Antonio Beasain Aranda,

PIHER-NACESA, Marketing Dep.

Telf. 948 82 04 50, fax. 948 82 40 50



Rotary Sensor/Potentiometer

Small Shock Detector


SAN JUAN CAPISTRANO, Calif. - October 17, 2001 - Endevco Corporation's Model 2479M4 is a small, low cost, high-volume shock detector mounted in a TO-5 package. It utilizes a self-generating piezoelectric seismic sensor that produces a high-impedance voltage output proportional to the input acceleration to the mounting surface. The shock detector is used for measuring high shock levels up to 20,000 g pk. Its primary application is as a fuse trigger for detonating ordnance. Operating temperature range is -40C to 50C (-40F to 122F). Weight is approximately 1.4 gms.



Shock Detector 2479M4

Quadrature Laser Accelerometer Calibration System


SAN JUAN CAPISTRANO, Calif. - October 17, 2001 - Endevco Corporation, the world's leading designer and manufacturer of dynamic instrumentation for vibration, shock and pressure measurements, announced that the National Institute of Standards and Technology (NIST), Metrology Division, has purchase d its Model 2916 automated quadrature laser accelerometer calibration system. NIST selected the Model 2916 Absolute Calibration Laser-Shaker for its ability to perform absolute calibration of accelerometers using method three of ISO 16063-11. This new technique can operate at much higher vibration frequencies than previous fringe-counting methods and is the only absolute technique that provides phase data. Designed to minimize the uncertainty usually associated with comparison type methods, the Model 2916 significantly expands NIST's calibration capability while improving ease of use. The 1/2 stroke shaker incorporates a high-performance Beryllium armature that allows for a wide frequency range. Design of the self-centering, air-bearing shaker armature achieves low waveform distortion and minimal transverse motion at low frequencies. A polarized Helium-Neon Quadrature Michelson Interferometer (laser) is used to achieve absolute calibration for frequencies ranging from 5 Hz to 50 kHz. Test transducers or Units Under Test (UUT) applications can be calibrated on top of the shaker, with the laser mounted beneath within a seismic isolation structure for the highest possible accuracy. Estimated uncertainty 0.5% 50 Hz - 5 KHz, 1% 5Hz < 50 Hz, 2% 1 to < 5 Hz, 20 KHz - 30 KHz.The Model 2916 laser-shaker is an absolute calibration module that is designed to be an integral part of the Endevco Automated Accelerometer Calibration System (AACS). A complete operating system consists of the Model 68357-0 calibration controller, 28978-0 vibration module and the 2916 laser shaker. The AACS is completely automated with add-on modules for maximum flexibility. It incorporates options such as the Model 28951B Shock Calibration Module to perform shock calibration from 20 to 100,000g using the comparison method.



Calibration system 2916


Geiger Mueller (GM) Detectors


Aptec-NRC Dover Division has prepared a new GM Tube Brochure that provides personnel who work with radioactive materials or radiation emitting machine with the technical information on these New Jersey made detectors, so they can replace their broken detectors. The available detectors are less expensive and have a 2-year warranty. To help the environment all Pancake and End Window Tubes are recyclable and a credit given for their return. Prices are fixed for at least a one-year period. For the new Catalog:


E-mail: gmtubeaz@aol.com

Fax: 973 361 9506

Aptec-NRC, 58 Richboynton Road,

Dover, New Jersey 07801



Industry's First 24-Bit Data Converter with On-Chip Flash Memory


The ADS1218 from Texas Instruments is a 24-bit analog-to-digital converter (ADC) with on-chip flash memory. It is the latest generation of high-performance data conversion products designed by TI for industrial process control, portable instrumentation, and test and measurement applications such as weigh scales, temperature measurement, liquid/gas chromatography, smart transmitters, and pressure transducers.


Optimized for high-performance, low-power systems, the ADS1218 offers 24 bits of no missing code performance, effective resolution of 22 bits, and less than 1mW power consumption. The precision on-chip voltage reference is accurate to within 0.2 percent and has very low drift (typically 5ppm/C). Also, linearity error is guaranteed to be less than +/-0.0015 percent of full-scale. The ADS1218 has 4K bytes of on-chip flash memory, which is programmable over the entire 2.7V to 5.25V operating range, providing the user increased levels of customization for linearization, serialization, calibration and data storage.


By combining such a high level of electronic circuitry on a small chip, the ADS1218 greatly simplifies the design of complex mixed-signal systems and reduces the need for external circuitry that costs significantly more than the single-chip system solution provided by the ADS1218. Additionally, the ADS1218 integrates an eight-channel multiplexer, programmable gain amplifier (PGA), input buffer, on-chip temperature sensor, burn-out current sources, dual independent current DACs, on-chip voltage references, external differential reference inputs, selectable data output rate, offset DAC, and eight programmable digital I/O. The serial interface is SPI compatible.


The ADS1218 is available in a 48-pin TQFP surface-mount package and is priced at $8.75 in 1,000 piece quantities. For free samples and more information on this product visit: http://www.ti.com/sc/ads1218x






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