Solid state paces sensor proliferation

Steve Massie has been in the electronics industry for 25 years. Massie holds a bachelor's degree in Electrical Engineering Technology from Northern Illinois University and an MBA from Roosevelt University. He can be reached at [email protected].

Sensors initially designed for aerospace applications are increasingly found in low-cost consumer products. Adding to this trend is the explosion in automotive electronics features that require more functionality in smaller spaces-attributes for products ranging from appliances to medical equipment.

Design News: What trends are you seeing in sensors today?

Massie: More intelligence is being added to sensors along with improved interface technology, such as digital and compensation, so sensors can do more and be plug-and-play, ready-to-go. Issues are who will supply what features, the vendor or the customer, depending on the arrangement. Lowering cost is always a big trend. Traditionally, even high-end sensors eventually make their way to low-cost consumer markets.

Q: What uses are forcing these trends the most?

A: Automotive applications are the largest sensor driver in the market. As automotive goes to more and more electronics, volume production drives costs down. Miniaturization strategies, such as converting from mechanical to solid-state technology, using MEMs, and fabricating discrete devices on a single chip, IC (or substrate), are another. And being able to fabricate such devices in high volume into tight spaces, on high speed, high precision automated assembly machines, also drives down cost.

Q: How can design engineers benefit from these technologies?

A: They can get more board space or put smaller boards into places they couldn't before, such as in consumer, health and medical, and automotive products. Now they can put more sensors into products, because those sensors are smaller and cost less.

Q: What are the major challenges faced by sensor users in developing applications?

A: In high volume commercial devices, the biggest challenge is probably cost and size. We see a lot of people in sensors converting from a mechanical device and going to lower cost electronics. We are at the stage where many tasks done by very simple mechanics are too expensive, for example a coin sorter for any currency. Electronics can actually be cheaper and provide a solution in a smaller package, in applications such as a hand-held blood pressure monitor. For sensor developers, a challenge is what to make standard on a device and what to make special or customized-trying to make something that everyone may eventually use, but trying to make it first for one customer.

Q: Where do you see new growth in the sensor market coming from?

A: The biggest single new growth market I see is probably fuel cells, particularly when the market goes from stationary to automotive uses. They need many sensors in these systems. It's happening now. A year ago, engineers were working on R&D. Today they have contracts and they are pumping out products for many types of stationary electric generation systems. Automotive is using the highest concentration of sensors already-and that's not with all the new toys they are going to put in them. And the cost-sensitive appliance market will eventually grow as functionality (heat and cold sensors, and air and water particle sensors) becomes more complex along with the need to get costs down. As it adds electronic content with by-wire systems, active suspensions, 42V electronics, and full-electric vehicles, the automotive market will continue to be the biggest sensor market.

Q: How much further can design engineers shrink the size of electronic components?

A: That depends on the product. You can't change the loads for a relay, for example. But for a sensor, if it can go on a solid state device then it can keep getting smaller. The laws of physics apply to size, diameter, and weight of pressure sensors and there are limits-you can't jolt a MEMs chip sensor with a pound of force-you can make the device smaller and limit its features. You can only cram so many amps through a given surface area.