Time-of-Flight System Detects Proximity to Protect Customer Service Workers

Dutch technology startup Aura Aware has designed and built a counter-top device leveraging STMicroelectronics technology to identify when customers are too close to a counter and illuminate a warning for them to take a step back.
Published: August 17, 2020

Several thousand companies seeking to protect their employees with safe distancing from the public are employing a product that uses time-of-flight (ToF) technology. The product turns red if an individual is too close to a desk or counter, and it stays green once the distance is safe. Netherlands-based entrepreneurs Janneke van den Heuval and Steven Kroon have developed the system to provide a simple, technology-based solution to protect workers.

The company the two have launched is called Aura Aware, with van den Heuval as its CEO and Kroon its CTO. The distance-awareness device is being used at stores and at the customer service desks of public-facing companies to help ensure that customers maintain a safe distance from staff members. The technology leverages STMicroelectronics‘ ToF FlightSense sensor, known as VL53L1X. The technology identifies if objects are in proximity to each other by transmitting photons and measuring reflection times to calculate the distance between them.

As long as a customer remains a safe distance from a counter, the system will illuminate in green.

Aura Aware launched the proximity-detection solution to address the COVID-19 pandemic, van den Heuval says. The cofounders say their company is dedicated to providing technology-based solutions for optimizing customer experiences related to physical spaces. “A lot of companies were searching for ways to maintain safe distances between employees and the public,” she states, but they wanted a system so simple it could be plugged in and set on a counter, without other configuration required. “We did a super-fast brainstorm,” she adds, and developed the system leveraging the ST sensor.

The resulting device is designed to be placed at a point of sale or other counter at which transactions with customers take place. The ST unit is an all-in-one device that includes a light emitter, a receiver array and onboard digital processing, which are combined to provide turnkey data to the host “without the need of heavy external processing, nor server data exchange through a server,” explains Thomas Viart, a marketing engineer in ST’s Imaging Group. The sensor emits photons out of an opening at the base of the device, directly into the space in front of it. As such, it is placed on a counter next to a salesperson or other worker, and it then begins measuring the proximity of members of the public who approach the counter.

Janneke van den Heuval

As long as it remains plugged in, the unit will glow a green light. If an individual comes closer than the accepted safe distance, such as 2 meters (6.6. feet), the device will detect that incursion based on ToF and change its color to red. As soon as the individual backs away, the light will return to its green state. Because the device is clear, the displayed light is visible on both sides so that the customer and the salesperson alike can see that their proximity is too close. The customer can then voluntarily step back upon seeing the alert, or the salesperson can point to the device and ask that he or she do so. The light can also flash and an audible sound can be produced.

After a user plugs in the device, assuming he or she is employing Bluetooth connectivity, that person can download the Aura Aware app so that a smartphone or tablet can recognize the unit, pair with it and enable the user to adjust the distance measurement—for instance, 2 meters (6.6 feet) instead of 3 meters (9.8 feet). Additionally, the user can adjust the sensitivity via the app, based on whether there is a great deal of light; very low light levels could affect the reflection response.

The company has sold thousands of the Aura Aware devices worldwide to date, van den Heuval says, and it can produce 2,000 to 4,000 units per week to fill new orders. Businesses around the globe have contacted the startup, including restaurants, car show rooms and agencies at which the public might need to provide passports or other information. The Aura Aware products were released in early May and the feedback has been favorable, she reports, adding, “Employees feel [safer]. We heard a lot of hotels didn’t like to put screens everywhere, so they are happy with a more elegant and guest-friendly solution.”

Among those using the technology is the Waldorf Astoria in Berlin, Germany. The device can be used in conjunction with clear plexiglass shields or screens. Selecting the STMicroelectronics unit ensured that the system would operate as intended, she notes, and that it could be developed quickly. “We looked at a lot of options,” she states, “but based on quality, price, availability, stock, speed and their willing[ness] to work with new businesses, [that] made them the best choice.”

The VL53L1X sensor

The ToF-emitted light is invisible to the human eye, Viart explains. Once light photons bounce back to the sensor, the measurement of true distance is accomplished using the light travel time and the speed of the light (distance equals time divided by twice light-speed). “Within a few millimeters square,” he says, “the miniature device detects a target up to 4 meters [13.1 feet] with very low power consumption.”

As part of the development, Viart says, Aura Aware used ST’s application programming interface and modified it to fit with its specific use case. Technology is now being developed for a variety of applications utilizing ST’s ToF system, he notes, adding, “You can expect to replace physical knobs by touchless switches. Our sensors are also able to detect basic gestures so they can be used for proximity detection.”

Moreover, the units are being used for content management and liquid level management. For instance, the sensors could be built into a gel dispenser that would provide cleaning agents only if someone’s hands were within close range. The company also developed a code to count individuals entering and exiting through a door, Viart reports, in order to identify the number of occupants within a given space. Regarding the Aura Aware solution, he says, “The ToF is the perfect solution for this use case because of the accuracy of distance our sensors can provide.”

Thomas Viart

FlightSense provides an accurate distance measurement ranging from a few millimeters up to 4 meters or more, Viart says. While other technologies like Bluetooth provide people detection with short radio wavelength at a long distance, he adds, “Exact location of an individual in the space is not possible.” As for Near Field Communication (NFC), he says, detection distance is much smaller and dedicated to near-field detection especially, which would be too close-range for the Aura Aware application. “We believe all technologies have pros and cons and can complement each other.”

“If you look at these kinds of hardware developments, it takes months—and this was done in weeks,” van den Heuval says. “That’s because every partner was aligned and willing to take a risk.” Marketing for the product in the United States is starting now, she adds, while many existing customers are in Europe. To provide a degree of sustainability, the company chose to employ wood instead of plastic for the device’s base. The long-term application for the device, she reports, will continue after the pandemic ends. “Even if, hopefully, the pandemic is over, it’s important for people to respect each other’s space. I do believe there might always need to be awareness of private areas.”