Feb 26, 2020Cloud technology and semiconductor company Wiliot has released a battery-free Bluetooth Low Energy (BLE) sensor tag that detects data such as temperature and usage, then forwards that information to a gateway or a BLE-enabled mobile phone or device. The tag, which is currently being tested by approximately 20 companies ranging from brands to retailers, captures energy from Wi-Fi, Bluetooth and cellular transmissions within the area.
The company expects to have the product available in large volumes later this year. Printer, label and software company SATO recently announced that it will work with Wiliot to build a solution with which SATO printers can both read and print the BLE sensor tags for use in Internet of Things (IoT) deployments.
Wiliot announced the first iteration of its product in 2019 (see Wiliot Unveils Passive Bluetooth Sensor), consisting of a tag that can draw energy from ambient radio frequency waves and use that power to send bits of data that amount to the tag's own unique ID number, as well as sensor readings. In that way, sensor tags do not require a battery and can thus be no larger than the size of a postage stamp.
The latest version, being trialed by companies this year, has a read range of about 3 meters (9.8 feet). It comes with encryption for security and a multi-core computer that recalibrates according to the RF environment, says Steve Statler, Wiliot's senior VP of marketing and business development. "This means we have more flexibility on putting our tags on different surfaces," he explains.
The result is a tag that not only operates on standard materials, such as wood or paper, but can also be applied to products such as wine bottles. The tag captures and stores ambient energy, then calibrates its responding signal based on the reflection and any variables caused by the wine bottle's surface. The collected tag data can then be transmitted to fixed beacons within the vicinity, or to BLE-enabled smartphones or tablets.
In a retail environment, the sensors provide information such as when a wine bottle is moved—on a store shelf, for instance, where it is picked up by a shopper—as well as that bottle's current temperature and what its temperature has been throughout the supply chain. In a consumer-facing solution, users could download an app that would identify when the phone was within range of a product. The user could then pick up a bottle of wine and view content on his or her own device, or on a dedicated screen, without the need to tap or scan a tag.
Traditional wireless sensors require battery power, while some technology companies have been developing passive RFID tags that can respond to interrogation from a reader using the power from that interrogation. The Wiliot product, however, uses a built-in beacon unit to send data via BLE broadcast, while it can receive power from multiple sources, even if it is not being interrogated.
The result is a tag that can be highly versatile and can send data any time it has received the necessary power. "That allows different harvesting strategies, depending on the environment," Statler says. For instance, a tag could capture transmissions from Wi-Fi units within a warehouse or at an assembly site, Bluetooth-based power from beacons in a delivery vehicle, and cellular transmissions from phones in the area.
The sensor tag can follow a product from the point of manufacture to when it is recycled. At the factory, as well as in warehouses, it can enable the tracking of both the locations and conditions of goods. Consumers can use the tag to capture content before or after a purchase, and the sensor can detect information about how the product is being used in the consumer's home. For instance, if it is sewn into apparel, the tag could detect how often it is worn, or if a washing machine or dryer had built-in connectivity, the tag could prompt the appliance to adjust its setting to match that item's care needs.
Throughout the past three years, the company has developed 10 test chips, with the most recent achieving the 3-meter transmission range and including encryption functionality for secure transmissions. Wiliot is now working to increase the product's robustness.
In addition to its partnership with SATO, the firm is also working with HP, whose Aruba Wi-Fi access points include Bluetooth beacons that can capture transmissions from Wiliot tags and energize them via Wi-Fi. "The nice thing is that very often the infrastructure already exists" to capture the sensor tag transmissions, Statler says, since BLE beacons are installed in many locations, and beacon devices are already in the hands of those operating smartphones.
In addition, Wiliot has been making strides in its manufacturing processes. The company started with hand-assembled tags. "Now we're collaborating with Muehlbauer and Avery Dennison," Statler says, "to deliver on the vision of using the same manufacturing processes used for NFC and RFID to create the semiconductor with a sensor." In that way, he notes, Wiliot is expanding its production from making hundreds of chips at a time to manufacturing with full wafers.
When it comes to security, the current chips offer 128-bit encryption. The company's Wiliot Ephemeral ID format (WEID) is designed to securely send private and encrypted ID numbers. There are two keys in every tag—one to encrypt the tag ID itself and another to encrypt the sensor data. The transmission is re-encrypted with every broadcast, Statler says, in a system the company calls Wave Computing.
"We're able to capture the weak signals," Statler states. "Then, rather than running monolithic computing tasks, we break that computing into chunks." For instance, he says one wave of energy could start up the processor, while another wave could accomplish sensing. More wave energy then launches the encryption, and yet another wave could accomplish the data broadcast. All of these transmissions can take place within a fraction of a second.
Twenty pilot projects are currently under way across a diverse group of companies, Statler reports. The goal is to test applications that would cover a product's life cycle, such as capturing data from the device as products are made, distributed, sold, used and recycled. For instance, one company testing the system is a major logistics firm that attaches the sensor tag to packages. Each tag transmits data to a BLE gateway in the delivery vehicle, and could also transmit to a BLE device built into a connected doorbell at the recipient's doorstep.
According to Statler, the company's expectation for future versions of the sensor tag is that it will offer a longer read range—as much as about 20 meters (65.6 feet).
