Sensor has magnetic personality
Tru-Position Magnetics claims its TPM sensor can do what no other sensor can:
accurately measure the X, Y, and Z position of an object through any solid
(non-magnetic) material. It consists of four Hall-effect devices (HED) arranged
in a circular pattern, like slices of a pie, and a separate, permanent-magnet
target embedded within the object to be sensed. Flux from the target generates a
current within each HED that varies with the relative position of the target.
Simple calculations combine the four outputs to produce the spatial position of
the target. Accuracies of 0.0002 in are possible. Applications include machine
tools, robotics, and automated fastening. FAX (408) 866-0348.
Miniature pressure regulator
Need closed-loop pressure control in a tiny package? Consider the MiniPR, created by Redwood Microsystems. The 3.2- x 2.5- x 0.85-in hybrid pc board contains a silicon micromachined pressure sensor, electronic feedback circuitry, and the company's innovative Fluistormicrovalve. Designed to handle non-corrosive gasses, it delivers plus or minus 1% full-scale accuracy over a range of 0 to 100 psi. FAX (408) 326-1899.
Superior position feedback
Celesco's PT9150 cable-extension transducer provides a precise, reliable alternative to proximity switches and encoders for telescoping hydraulic cylinders and multi-segment actuators. Quick to install, the sensor is insensitive to alignment and requires little maintenance. Contained within a sealed NEMA 4 housing, the unit's stainless-steel cable winds around a drum monitored by an optical encoder. By attaching the cable to the end of a telescoping cylinder, users can derive both position and velocity. The PT9150 is accurate to 0.04%, repeatable to 0.02% full stroke, and boasts essentially infinite resolution. It is available in measurement ranges up to 1,200-in. FAX (818) 340-1175.
Accelerometer cuts costs
Silicon Microstructures' new 7130 variable-capacitance accelerometer delivers high performance at one-tenth to one-twentieth the cost of conventional technologies. Available in plus or minus 2g to plus or minus 300g full-scale models, the 2g part provides usable resolution down to 200aeg. "It can sense a Q-Tip dropped from two inches at the opposite end of a conference table," says company President Jim Knutti. A built-in ASIC detects and amplifies the sensor's signals, providing compensated and calibrated output of plus or minus 1V. Applications include shock testing, event recording, medical monitoring, and even down-hole drilling where it serves as an inclinometer. FAX (510) 490-1119.
Two chips are better than one
IC Sensors Model 3255 accelerometer offers an advantage no automotive engineer can resist: It's cheap. Designed for frontal- and side-impact airbag systems, the new sensor cuts costs by separating the sensing element and the trimming electronics into two chips. The sensing element is the company's classic micromachined silicon strain-gage. But instead of adding thick-film resistors for calibration--as in the past--engineers placed the trimming functions in a separate ASIC. FAX (408) 432-7322.
Crack open most small, portable disk drives and you'll find a tiny accelerometer. Its job: detect severe shocks and stop write operations before the read/write head flies off track. AMP has supplied thousands of piezoelectric polymer accelerometers for this job. Trouble is, each customer's demands are different. The