Personalizing Personal Fitness

Jintao Zeng – Global Product Manager, NXP Semiconductor’s Microcontroller Group

A significant driver in the growth of wearable devices is fitness monitoring applications. These applications are either embedded in the code of a purpose built device, such as a Fitbit®, or managed via a download into a Smart Watch. The application is also linked to the user’s smart device for both controlling workout related features and displaying the data via a dashboard. Fueled by consumers’ growing passion for living healthier lifestyles and using workout data to track progress and share socially with their connected friends or health care providers, this trend will continue to rise for the foreseeable future. These fitness oriented wearable devices are also incorporating more features that take advantage of a wider range of sensor types and the corresponding data captured. The additional data captured feeds into the application’s cloud based analytics and data visualization tools to keep users even more engaged. The next wave in the connected physical-fitness experience will extend to personal training equipment designed for use in either a gym or the home. The personal training equipment will not only connect with the wearable device via the smart phone but also open up new business model possibilities for both gyms and the personal fitness equipment manufacturers. In this article, we’ll explore both the design considerations and business opportunities this new model presents.

avt-201606-nxp-article3-img1bTo start, consider the following use case. A person looking for a cardiovascular workout at the gym decides to use the treadmill. They start by tapping their smartphone, which has a fitness tracking application linked to their wearable fitness band, on the treadmill to activate its features. The treadmill first connects up through an Internet of Things (IoT) enabled gateway to the cloud to authenticate the individual and in turn push down to the gateway specific workout settings and personalized features, such as preferred dashboard template for the display, associated with the user. As the workout begins, sensors in the treadmill monitor speed and the incline and feed the data through the processor up to the gateway where it is analyzed for actual performance against the individual’s target fitness goals. If the analysis indicates the user is not as active as they need to be to hit their goal, a signal is sent back to the processor which in turn signals the motor driver to increase the rate and also the incline of the track. The processor also interacts with the display and can send motivational messages to pick up the pace and trigger more upbeat music to play from the user’s pre-defined playlist. Connectivity features will also allow the person to see which of their friends are working out at the same time and how their performance compares. At the end of the workout, the individual’s performance data is stored and the gateway is notified to end the person’s session and remove their workout configuration.

These fitness oriented wearable devices are also incorporating more features that take advantage of a wider range of sensor types and the corresponding data captured.

The technologies required to deliver this type of solution are available today and the designer has multiple component options depending on their business objectives and design priorities. NXP has a robust portfolio of technologies for enabling this solution, all of which are optimized to integrate across the various functional blocks of the system, to enable faster design and time to market. Several of these options will be described below and are shown in the accompanying block diagram.

Processor: NXP has several families which are all viable for this solution including the Kinetis W series, if security and connectivity are the drivers, i.MX6 and i.MX7 for security and HMI, or the LPC family for low power. For example. the i.MX7D, delivering heterogeneous processing with dual ARM® Cortex®-A7 cores and Cortex-M4 core, is an option based on the ability to partition workloads, provide advanced connectivity and deliver a ‘Fortress of Security’ to protect personal data from being compromised in a public space. Your Avnet account executive and field application engineer can assist you with selecting the right NXP processor or controller for your requirements. You can also review, compare and purchase a number of different reference designs and development platforms for each of the NXP processors from Avnet’s digital portal.

Power Management: NXP Power Management Integrated Circuits (PMICs) provide highly integrated, high-performance power management solutions for a wide range of applications. With the integration of power management, system control, battery management, interface and audio functions, as well as other system specific functions, the PMICs are designed to offer optimum performance for a wide range of devices. Leveraging high-performance process technologies, NXP PMIC’s offer high-efficiency solutions designed to extended battery life and reduce power dissipation. For this example, the PF3000 was chosen as it is designed to support the i.MX7D specifically. Key features in the PF3000 include PFM/PWM or APS (pulse skipping mode), programmable output voltage, sequence, timing and quick turn customization (OTP configuration).

Sensors: NXP’s sensor portfolio is a one-stop shop for a wide range of robust, highly accurate and reliable sensor devices. NXP utilizes Magnetoresistive (MR) sensor technology which perform their measurement duties without needing to touch the parts they are measuring. This means wear-free operation that doesn’t affect the measurement process. For the connected treadmill application, an accelerometer and gyroscope were included. The FXLS8471Q accelerometer is highly versatile and ideal for high-performance, low-g applications that offer noise density, board mount offset, temperature performance and sensitivity. The benefits of these features include accurate low angle tilt detection, stability over temperature for varying environments and interrupt based detection of very small signals. The FXAS21002C 3-axis gyroscope complements the accelerometer with smart sensing technology that enables events with durations shorter than the sample time to be captured and processed, reducing the real-time processing requirements of the host. The FXAS21002C also delivers extremely low power operation with advanced embedded features enabling significant system-level power savings and is user configurable to generate an interrupt when an event threshold occurs on any one of the sensing axes.

Motor Driver: NXP offers multiple driver products in various configurations including fully integrated H-Bridges, MOSFET gate drivers and fully configurable high-side and low-side switches. In this application, The GD3000 is a gate driver IC for three-phase motor drive applications providing three half-bridge drivers, each capable of driving two N-channel MOSFETs. The GD3000 is able to drive powerful motors requiring large FET drivers for desired speed and torque. The device also features real-time fault monitoring allowing protection of external FETs and the motor. Given the need for fast and precise motor speed changes to match the individual’s workout objectives, the GD3000 is well suited for the application.

Near Field Communication (NFC): NXP NTAG I²C plus is a family of connected NFC tags that combine a passive NFC interface with a contact I²C interface. As the second generation of NXP’s industry leading connected-tag technology, these devices maintain full backward compatibility with first-generation NTAG I²C products, while adding new, advanced features for password protection, full memory-access configuration from both interfaces and an originality signature for protection against cloning. The NT3H family comes in multiple package and memory options. It delivers a very low cost, secure solution and is able to operate with low power requirements by utilizing existing energy sources.

Collectively, these products from NXP are easily integrated to deliver all of the features needed for the connected treadmill. Design tradeoffs are easily accommodated with other devices available from NXP’s robust portfolio within each of the individual product categories. Additionally, Avnet offers the Agate IoT gateway which features the NXP QorIQ® LS1021A communications processor. The gateway is able to handle several distinct application workloads and translate numerous bus protocols to streamline communication up to the cloud. Developers looking to customize a gateway to complement the connected fitness equipment will appreciate the available features and support.

avt-201606-nxp-article3-img3The connected treadmill opens up new business models and potential efficiency gains for both the OEM and the fitness center operator. The connectivity and personalization enables services like scheduling time on the equipment or consumption based subscription models. It also enables access to other subscription services such as customized content like a virtual personal trainer for example. On the efficiency side, the treadmill can feed runtime data up into the cloud in support of predictive maintenance and monitor for potential failures before the machine goes down. Finally, gyms can create competitions, promote social networking among members and offer other loyalty programs to keep customers engaged in the highly competitive gym membership market by utilizing the connected equipment in their facilities.

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