The SensorTile development kit from STMicroelelctronics continues to pop up in an eclectic selection of applications, from basketball and tennis to the medical field. And now, for the first time ever, SensorTile enters the world of jewelry thanks to the Smart Barakà, a connected bracelet that can track steps, and calories as well as filter phone calls, serve as a PowerPoint remote control, or vibrate to signal notifications from a smartphone.
Made by Barakà, an Italian jeweler, the Smart Barakà is available in three colors (blue, green, and black) or in a luxurious gold limited edition. Beyond the appeal of smart jewelry, the bracelet is the ultimate case study for the IoT revolution conquering unexpected markets and what it means for a company like Barakà to enter the world of electronics thanks to ST.
Indeed, the Smart Barakà was possible because of the SensorTile. The company doesn’t assemble its product in a traditional electronic plant but a jewelry factory that has absolutely no experience with soldering components on a PCB. It was thus imperative that Barakà get a complete and functional module that it could easily drop into its product and that would only require a couple of screws.
The module also had to be weather and splash proof to meet the standards that customers expect when they buy a jewel like the Smart Barakà. As a result, the jeweler uses a protective coating in resin that still lets the air flow through to ensure the microphone works correctly.
These design considerations show that the module’s layout was one of the biggest challenges, which explains why the company chose the SensorTile platform.
Function without betraying style
At the heart of the Smart Barakà is the STM32L476JGY6, the same microcontroller that’s on the SensorTile and that serves as the main host for the sensors as well as the Bluetooth module.
One of the main reasons Barakà chose this MCU was its performance-to-power-consumption. Unlike the vast majority of smart wristbands on the market today, the Smart Barakà is a piece of jewelry first.
As a result, it needed to keep the aesthetic and design that makes the other Barakà jewels unique, which meant keeping a small battery while also ensuring enough juice for a satisfying user experience. A bracelet that’s too thick and heavy because it needs large power cells is unacceptable.
The STM32L476JGY6 has many low-power modes to optimize the system’s efficiency. For instance, Stop 2 mode can still use a Real Time Clock but reduces the power consumption to only 1.4µA.
Additionally, if a user really becomes idle, it is possible to use a standby or shutdown mode, which can lower the power consumption up to 30nA.
And since the MCU offers a Batch Acquisition Mode, it is still possible to collect data from the sensors while using power-saving features, then process the information once the system wakes up. Thanks in part to the MCU, the Smart Barakà can thus last 24 hours in idle and four to six hours in constant use. It means that in most cases, the bracelet will last an entire workday without betraying its style for the sake of function.
Style Without Compromising Function
Even though the Smart Barakà is a piece of jewelry, its customers are still expecting all the features associated with an electronic wristband. This is why the company relied on the densest sensor board in the world, the SensorTile.
The bracelet integrates the LSM303AGR magnetometer, the LSM6DSM inertial sensor, the LPS22HB barometer, and even the MP34DT05-A digital MEMS microphone. As a result, the Smart Barakà can take voice memos as well as count steps and measure altitude changes in case someone is running on a hill. The PowerPoint remote also uses the inertial sensor to translate movements into commands.
These features are important because even if Barakà is obviously not expecting athletes to use its products for training purposes, it will ensure that busy executives and other high-functioning business clients with a potentially sedentary lifestyle get the motivation and information they need to remain active and productive.
Another significant advantage of the SensorTile is that it saves engineering teams a tremendous amount of time. By using a compact and feature-rich reference design, they can spend less time on the hardware, and more time on the applications that will differentiate them from the competition. In the case of the Smart Barakà, that meant optimizing the software’s accuracy by excluding false positives and better processing the sensors’ data to more accurately reflect the users’ activity.
It demanded a lot of trials and errors, necessary improvements in the original models and fine-tuning some assumptions by taking into account additional factors and metrics. They used the SensorTile hardware and some of the low-level code such as drivers, but they built the rest from scratch to optimize the system and save on processing resources and energy.
The Smart Barakà Journey
Another critical advantage of the SensorTile was the presence of our BlueNRG-MS Bluetooth network processor and the BALF-NRG-01D3 balun right into the reference design. One unsung truth among design companies is that Bluetooth can be complicated. It often demands that teams outsource the antenna design and tuning before they can even consider applying for the complex but necessary certifications.
It is actually common to see a company delay a product for months because of Bluetooth issues. Moreover, when we factor that Barakà is a jeweler that is entirely new to this world, the SensorTile’s appeal becomes undeniable. By using this reference design, the jeweler takes away a lot of the complexity and dramatically reduces the time it takes to receive the proper certifications.
Looking at the intricate design of the Smart Barakà, its fashion statement, and its impressive feature-set, it is clear that the journey from prototype to mass production was arduous. SensorTile didn’t remove all obstacles, but it made it possible for a company like Barakà to create an entirely new niche of products.
By using ST’s expertise, the company was able to apply its own experience where it mattered most. There are clearly customers that do not respond to smartwatches and who will appreciate the ability to enjoy smart functionalities without compromising the identity they wish to project. With SensorTile, Barakà can bring them a bracelet that will meet their standards without sacrificing the features they expect to get.