UltraSense Systems’ “Smallest Ultrasound SoC” Designed to Turn Any Surface Into a User Interface

January 03, 2020 by Cabe Atwell

The TouchPoint ultrasound sensor utilizes sound waves to turn any surface into a touchscreen, eliminating the need for physical buttons.

UltraSense Systems has unveiled a new sensor capable of turning any surface into a touchscreen interface, including materials not typically associated with the technology, including wood, metal, ceramic, and plastic.

The company’s TouchPoint ultrasound sensor can turn those surfaces into a virtual button or gesture, eliminating the need for physical buttons in the same way the iPhone did away with physical keyboards on phones. 


3D ultrasound sensor

The TouchPoint series is 3D ultrasound sensors. Image used courtesy of UltraSense Systems

In a recent press release, UltraSense CEO Mo Maghsoudnia explained, “We have seen a shift in the way we interact with our devices, where digital has replaced mechanical, and the move to virtual buttons and surface gestures is accelerating. The use of ultrasound in touch user interfaces has not been implemented in such a novel way until now."

He continues, "Our family of TouchPoint ultrasound sensor solutions enables new use cases that allow OEMs to bring a differentiated user experience with a wider variety of touch and gesture functions under virtually any material and material thickness.”


How TouchPoint Sensors Work

UltraSense feels its new TouchPoint sensors could improve the way we interact with the technology we use every day, including home appliances, vehicle door handles, gamepads, earbuds, and AR/VR headsets, among a host of other applications.

The sensors (about the size of a ballpoint pen tip) offer a new approach to haptic interfaces by being able to detect minute sound waves traveling through a surface. When touched, the sound waves traveling through a surface are altered depending on the action. The sensor discerns these sound waves as different kinds of touches, allowing for multifunctional gesturing.

For example, key inputs could be incorporated into the sides or back of a smartphone for gaming or taking pictures.


"World's Smallest Ultrasound SoC" 

According to UltraSense, the TouchPoint product line offers the world’s smallest ultrasound SoC (system-on-a-chip) for highly localized sensing on both thick and thin surfaces, while consuming minimal uA current in always-on mode.


TouchPoint 3D Z-force sensing

The TouchPoint line uses 3D Z-force sensing, which provides a gram-force measurement for applications that require the use of gloves, external cases, and water/ice rejection. Image used courtesy of UltraSense Systems


They also don’t require a device’s host processor to function because all the algorithm processing is done on the sensor SoC itself. Its versatility allows it to be used as a stand-alone power button, shortcut keys, and volume adjustment, as well as wake-on-touch sensing, which could power on an entire device with a touch.


Anatomy of TouchPoint Sensors

On the technical end, the TouchPoint sensor SoC was designed using an ASIC with an embedded microcontroller, memory, and analog front-end, along with an ultrasonic transducer in monolithic silicon die.

The sensors incorporate UtraSense’s U-Sense self-regulating, input-detection classifier algorithm, which detects changes to acoustic properties and classifies input materials. It also allows for adjustments in manufacturing variations and environmental changes, which provides minimal development tuning and time-to-market for new devices. 


Three Versions

The TouchPoint series comes in three versions—TouchPoint, TouchPoint Z, and TouchPoint P—with support for different material thickness, voltages, and applications, as shown in the chart below:


TouchPoint series

Specifications for three versions in the TouchPoint series. Image used courtesy of UltraSense Systems


While the sensors offer slightly different specifications, they share many fundamental features, including the ability to operate separately from a host processor. They also have wake-on-touch capabilities and can discern touch and force levels.

All three versions are immune to contaminants, acoustic interference, and electromagnetic fields. UltraSense also claims that the devices have no mechanical design restrictions and no cross-talk between sensors. The company asserts that the sensors are also simple to set up with one-time calibration and easy sensor attachment.

The transducer can be switched off, allowing the sensor to drive piezo materials to support large touch interfaces, such as trackpads in automobiles and integrated mousepads on laptops.


The Trend to Minimize Mechanical Inputs

On the input end, the TouchSense series can accept tapping (single and double), tap and hold, multi-touch, sliding/swiping, and trackpad, giving them versatility for a myriad of applications.

Companies such as Apple and Samsung have been at the forefront of creating products with minimal mechanical inputs, such as the controversial removal of the headphone jack in the iPhone 7 and Samsung following suit with the Galaxy Note 10. 

The trend is expected to continue with new smart devices over the coming years, and TouchSense is looking to capitalize on the endeavor by providing a new interface technology rarely seen since the original iPhone debuted.


Touch screen

UltraSense Systems suggests that the new ultrasounds sensors can "replace mechanical buttons and sliders with touch sensing surfaces for sterile environments that use harsh cleansers." Image (modified) used courtesy of UltraSense Systems

Semico Research ASIC market analyst Richard Wawrzyniak feels the same, stating, “The UltraSense TouchPoint ultrasound sensor is a unique and innovative addition to the list of solutions for user interface capabilities. This gives industrial designers a really useful option to differentiate their products while improving performance without adding to clutter."

He remarks, "Needless to say, the ‘cool’ factor in products that employ this technology is going to be very high. Semico thinks this product is going to very successful as designers discover what they can do with it.”

UltraSense Systems’ TouchPoint series of ultrasonic sensors have already been tested by smartphone manufacturers and is currently ready for production. The company is expected to showcase the new line at this year’s CES 2020 conference in Las Vegas this month (January 7–10).