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Inductive sensing takes interface design to a new level | Cypress Semiconductor

Inductive sensing takes interface design to a new level

Have you ever gotten grief from your spouse, parent, or roommate for leaving the refrigerator door open, usually instigated by an annoying alarm? That’s inductive sensing at work. Same for other types of sensors and metallic touch interfaces that we’ve all become accustomed to throughout our homes – from microwave ovens to washing machines and smart lock systems.

Inductive sensing has become increasingly popular for innovating the industrial market, because of the robustness and appealing aesthetic qualities it adds to these industrial designs. It’s application spans a wide spectrum of uses, often tapping into its unique operational abilities. These include functioning in harsh conditions, even underwater, with a high degree of accuracy in certain measurement and inspection use models, and where extreme flexibility is required in the end product. You’ll find inductive sensing in cars, factories, medical laboratories, wearable devices, and yes, in that automated coffee maker you rely on every morning.

The IoT has been a strong driver of inductive sensing use, as designers seek sleeker and more efficient user interfaces that work in all types of environments, without increasing the BOM. Its metal-to-metal capabilities allow high-quality metal overlays, which are difficult to sense through with other sensing methods, but still provide the elegance and ruggedness that many products require. 

Inductive sensing defined

So, what exactly is inductive sensing? In a nutshell, it’s a contactless sensing technology that works on the principle of electromagnetic coupling between a sensor coil and the metal target to be detected. Its strength lies in applications that require metal detection, either as the change in position of a metal target or a change in shape through mechanical bending, by application of a force, for example. It can detect the presence of a floating piece of metal, as well as distinguish different types of metal. In very simple (but practical terms): think about a paper copier finding that potentially damaging staple that came loose.

The inductive sensor generates a magnetic field between the sensor and the metal target which is insensitive to dirt, oil, and other normally disruptive and destructive elements. It’s also resistant to water, meaning it’s great for things that must operate outdoors in the rain or even in a product like a waterproof Bluetooth speaker. 

Here are some typical applications where you will find inductive sensing:

Inductive Sensing

The challenges and the PSOC 4700 solution

While inductive sensing creates several possibilities for improving the user experience and reducing the cost of products, it has traditionally been viewed as somewhat difficult to implement. Product developers have struggled in the past with the high degree of analog expertise needed, the fact that end applications require time-consuming manual tuning and calibration for robust performance, and complex algorithms need to deal with variations in manufacturing and environments, like extreme temps and humidity.

Factor in cost issues, particularly the traditional approach of having to use a multi-sensor solution that requires multiple, discrete, and costly IC, and product developers are looking to find more efficient ways to use inductive sensing.

Enter Cypress: We have a long track record of solutions for capacitive sensing, integrating that capability into our PSoC platform. We call that CapSense® and it has been used in many designs. It’s a great foundation to expand our reach into inductive sensing and offer capabilities that capacitive sensing cannot.

With our PSoC 4700 series, we are delivering an enhanced single-chip solution built on our well-known cost-optimized and programmable architecture that extends our sensing portfolio into inductive sensing. We’re calling the new offering MagSense™ in a nod to its focus on electromagnetic coupling capabilities. Integrated in the PSoC 4700 MCU family , it makes inductive sensing as easy to use as our industry-leading CapSense solutions - and, better yet, designers can combine both sensing techniques with a single chip.

It can support up to 16 sensors to implement buttons, linear and rotary encoders, linear sliders, and proximity sensing. With the MagSense inductive-sensing technology in PSoC 4700 MCUs, it provides advanced algorithms that automatically take care of environmental changes and stress caused by excessive use. In addition, the PSoC 4700 MCU features AutoTuningTM, that automatically compensates for manufacturing variations, simplifying designing a production grade solution.

The solution provides a quick visual for problem solvers to envision their solutions. For example, the displacement metal-over-inductive sense buttons lets designers feel the potential of solid state pressure switch not dependent on the capacitive properties of the activating device, so it doesn’t matter if it’s a gloved or raw hand pushing on the displacement button.

What almost every designer loves about PSoC is part of the inductive solution too: our very intuitive and user-friendly PSoC Creator™ Integrated Design Environment (IDE), which allows users to drag and drop production-ready hardware blocks, including the new inductive sensing MagSense component.

If you’re looking for way to leverage the capabilities of inductive sensing. MagSense is the ideal solution: Easy-to-use, with best-in-class performance. For more details, click here…and make sure the fridge door is closed while you’re at it.​

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