Heart rate monitor for athletes uses wireless technology

The MIO Alpha sports watch employs optical technology to accurately and continuously measure heart rate of athletes without requiring a conventional heart-rate strap. Measured data can be transmitted live or after training to any Bluetooth v4.0 enabled smartphone via a Nordic Bluetooth low-energy wireless link.

The sports watch uses a Nordic µBlue nRF8001 Bluetooth low-energy connectivity IC (integrated circuit or chip) from Nordic Semiconductor to communicate live or stored training data directly from the wrist to any Bluetooth v4.0 enabled smartphone or device.

The device is designed for both serious amateur and professional athletes and uses an electro-optical cell with a pair of optical sensors on the underside of the watch to track blood flow volume in the wrist as it pulsates with the rhythm of the heart to extrapolate heart rate.

“This technology enables the MIO Alpha sport watch to measure a user’s heart rate without an uncomfortable strap at performance speeds up to 12 mph [19 km/h] with the same accuracy as traditional EKG/ECG [electrocardiogram]-based heart-rate straps,” comments Emily Rothwell, VP of Sales and Marketing at Physical Enterprises Inc, the company behind the watch.

“Achieving this level of end-user simplicity without compromising accuracy compared to a traditional heart-rate strap wasn’t easy,” admits Rothwell. “An onboard motion detector and built-in noise filtration software developed by Philips compensate for arm movements and perspiration typical of fast running and cycling, which can all interfere with blood flow measurements.”

The low power and RF performance characteristics of the µBlue nRF8001 Bluetooth low-energy connectivity chip enable the device’s built-in rechargeable lithium ion battery to offer up to 10 hours of ‘live’ heart-rate smartphone-linked monitoring (its most energy-intensive operating mode). This ensures reliable performance even in demanding 2.4 GHz operating environments such as busy, modern gyms that can house numerous local active devices and emitters (in particular, Wi-Fi) all working on the same frequency.

In operation, it can be used as a stand-alone device and includes features such as workout timers, continuous heart rate display and audible heart-rate zone alerts, or in conjunction with some smartphone apps.

Geir Langeland, Nordic Semiconductor’s Director of Sales & Marketing, says: “Strapless heart rate monitoring is a welcome addition to the sports and fitness sector and joins a growing list of monitoring options that can be used stand-alone or with a smartphone thanks to Bluetooth low-energy wireless technology.”

For more information on the product, go to www.mioglobal.com and www.alphaheartrate.com.