How can you get more than one measurement from a single sensing technology?

Getting more than one sensor measurement from a semiconductor sensor package that is perhaps 50% or more smaller than one commonly used a decade ago is no problem. Two and even all three of the accelerometer, gyroscope and magnetometer (AGM) sensors found in an inertial measurement unit (IMU) commonly found in a smart phone are easily found in a small surface mount integrated circuit (IC) package. And, each one of these sensors measures all three axes, so an AGM provides nine degrees of freedom (nine measurements) unlike the first microelectromechanical systems (MEMS) accelerometers that only provided a single axis measurement.

Since some pressure, accelerometer, tilt and other sensors require temperature measurements either for integral temperature compensation, proper operation or improved accuracy, it is also possible to find an IC packaged sensor that also measures temperatures and provides an output to the user.

Some manufacturers offer pressure and temperature measurements from a single package (threaded, stainless steel and more) that goes well beyond the plastic packages commonly used for semiconductor based sensors.

The real trick is using a single sensing technology to get more than one measurement.

Chemical sensors including gas concentration sensors often measure more than one parameter and provide an excellent example of one sensor, several measurements. Using arrays with different areas sensitive to different chemicals/gases, a single sensor can measure and/or detect several different chemicals/gases.

Some sensing technologies are used for more than one measurement technique such as piezoelectric technology. The piezoelectric technique is commonly used for acceleration, vibration, shock and pressure. A specific sensor design usually optimizes the sensor for measuring a specific parameter. Piezoresistive and capacitive technologies are also used in a variety of measurements.

With today’s advanced packaging techniques, compromising the capability of a single sensing technique to make disparate measurements is probably not a good idea. The sensor is often a small part of the total cost of signal conditioning, amplification and packaging without considering other IC technologies that can be included in the same sensing package. Array type sensor designs provide an exception to this.