Two things that tend to capture my interest in an article are sensors and cars, and Bill Schweber’s entertaining post in a recent EE Times featured both. So I was entertained.
He started out with the familiar problem of the “check engine” light coming on. We’ve gotten so used to that warning that most of us no longer feel we need to high-tail it into the dealer before the engine explodes. Instead, if you’re an engineer and/or a car guy, you do a bit of poking around to figure out what the problem is. (In Bill’s case, it was a “faulty sensor in the coolant system.” Good – I guess – to learn that fault wasn’t in anything to do with the actual operation of the car, but with the sensor.
As Bill points out, our cars are equipped with an ever-growing number of sensors. This, in turn, will lead to those pesky false alarms.
To me, the modern super-sensored car is a forerunner of the much-heralded Internet of Things (IoT). Indeed, for many car models, it is an IoT scenario as the car is connected back to the manufacturer to report various readings, status, and events, like it or not. Whether the car is directly connected as an IoT node or not, today’s cars are sensor-laden vehicles with self-awareness of many temperature, pressure, flow, and switch-on/-off readings. We’re told that this is all good.
But I’m not so sure. As any experienced engineer knows, sensors are the most vulnerable part of a system. Due to their inherent role, sensors are exposed to the nasty real world of moisture, vibration, temperature, and other physical stresses to a lesser or greater extent. Sometimes the exposure is directly due to what is being monitored, but often it is a side effect of monitoring some other parameter. Regardless of the cause, sensors live a much harder life than the electronics on the typical PC board, even if that board is in an automotive environment. (Source: EE Times)
He then talks about the problem of sensor proliferation which is that, with so many sensors the potential to throw off more and more false positives and negatives, testing and assessing – and figuring out how to test and assess – is becoming more and more difficult.
Bill offers a couple work-arounds that, as he points out, aren’t so great. One is adding redundant sensors and interface circuits. A second is “to implement a true, independent, closed-loop test of the sensor performance,” which is practical for some situations, but not for others.
There are two main outcomes to the increasing number of sensors. One, people will have more and more alarms to ignore, and ignore them they will, given that so many of the warnings end up being false alarms. And two, “test engineers will have to spend even more time devising algorithms that correlate multiple sensor readings to see if they can “tease out” a better conclusion as to which readings are correct and which are in error.”
Fun read, this article. Definitely worth checking out if you’re a sensor and/or a car enthusiast.