Much of our work has involved sensors and transducers, instrument design and applications. This page is a labor of love: sensor technology intrigues us. We’ve learned a lot over the years and are still learning.

Most sensor users are not electronic designers but rather are people who design, program and apply sensors to robotics, automotive, aerospace, military, industrial and other applications. Our hope is to make sensor technology understandable. We’ll be writing for the user, not the researcher or sensor designer. No calculus, theoretical physics or the like.

We’re starting small, growing over time. Come back and visit us often. We’ll be adding more info periodically as time permits.

Temperature – Which Sensor is Best?

Thermocouple? Resistance thermometer (RTD)? Thermistor? Silicon sensor? Each has its own advantages and limitations. The choice depends on your needs and applications. This white paper examines and compares them to help you understand and choose.

Ultrasonic Leak Detection

Pressurized gas leaks emit an audible high-frequency hiss but have even more energy at ultrasonic frequencies. Small leaks give off detectable ultrasound long before they become large enough to hear. Ultrasonic leak detectors specifically respond to ultrasonic emissions, ignoring audible sound. Because of this, leaks can be “heard” at a distance, even in noisy industrial environments.

This white paper, based on a project done years ago, explains how they work and how they are used: White Paper: Ultrasonic Leak Detection

And – here’s a link to a similar article, written for and published on Control.com: Ultrasonic Leak Detectors – Finding Leaks with Ultrasound.

Temperature Sensor ICs

Silicon integrated temperature sensors have become the predominant way of measuring ambient and moderate temperatures. Like thermistors, they cover roughly -50 to +150 degrees C. Unlike thermistors, they are easily applied because they include analog and/or digital circuitry on the same chip as the sensor itself.

This paper describes the basic measurement technology then surveys the multitude of choices available. Analog, pulse and digital outputs are covered as are other optional functions. Accuracies, package styles and costs are summarized.

White Paper: Temperature Sensor ICs

Humidity Sensors and Measurement

We set out to review and cover a range of humidity sensors. Somewhat to our surprise, we found that almost all the readily available and easy to use sensors use the same technology, humidity-sensitive capacitance. For just a few US dollars you can buy relative humidity (RH) sensor ICs with either digital or analog output. Typical accuracies are 2% to 4% RH. Most include temperature sensors.

This paper covers them in some detail. It then describes the relationship between RH and dew point and the basics of cooled-mirror dew point measurement. It closes with brief reviews of several other humidity measurement technologies.

White Paper: Humidity Sensors and Measurement

Here’s a link to a similar article I wrote for Control.com.

And – here’s a link to an article specifically about MEMS IC humidity sensors, written for AllAboutCircuits.com

Thermocouple Types – Which One is Right for You?

No thermocouple can meet all needs. There are several standard types. Some work best at high temperatures, others in cold and cryogenic applications. Different types are compatible with different atmospheres. Some like oxidizing but are damaged by reducing atmospheres: others are just the opposite. Some, containing iron, are damaged by hot water vapor. Accuracy can be degraded if metallic vapors diffuse into their metals.

Weve written an article covering thermocouple selection, published on website Control.com. To read it, click here.