Sensors Blog–Grading Comments

This week was a particularly successful one.  You covered a wide range of sensors and addressed the physical principles behind most of them quite well. What follows are some specific comments:

• A few of you recognized explicitly that what is actually measured in most cases is NOT the variable of interest, instead it typically an effect of that variable that lends itself to measurement – typically electrical, but not always.
• One aspect that almost no one addressed was the response time of the various sensors.  Some of them (e.g. many humidity sensors) can take many seconds or even minutes to generate a reading, whereas other can have response times of milliseconds or even less.
• Accuracy and repeatability were important aspects that appeared in a few of your posts, as was the longevity.  Associated with longevity is the idea of sensor “drift” over time, requiring recalibration of instruments that must be precise.