Bluetooth LE knee brace provides wireless heating/cooling therapy for user recovery 

RecoverX Image press release

RecoverX’s Contrast Knee employs Nordic nRF52832 SoC enabling user to control temperature from a smartphone app via Bluetooth LE

Nordic Semiconductor today announces that U.S.-based technology startup RecoverX has selected Nordic’s nRF52832 Bluetooth® Low Energy (Bluetooth LE) System-on-Chip (SoC) to provide the wireless connectivity for its ‘Contrast Knee’, a wireless knee brace that provides electric-powered alternating heating and cooling therapy. 
Contrast Knee is strapped around the user’s knee and employs built-in temperature sensors that regulate and sustain precise temperature therapy for all phases of recovery to help the user successfully manage inflammation, relieve pain, and return to an active lifestyle. The battery-operated wearable device reaches optimal therapeutic temperatures in under 60 seconds at the touch of a button to deliver recovery support for the user whenever and wherever required - without the need for ice, water, or mains power. 


Wireless control

Using the Bluetooth LE connectivity provided by the Nordic nRF52832 SoC, the user can control the heat, cold, or contrast temperature therapy from the iOS and Android ‘RecoverX’ app on their paired Bluetooth 4.0 (and later) smartphone. The companion app allows the user to customize their Contrast Knee therapy by selecting the specific temperature and duration of the session, as well as track the total time and time remaining, monitor the delivery of the optimum heat range and/or optimum cold range throughout the session, review the history of their therapy sessions, and access helpful recovery resources. Contrast Knee uses a 21700 Li-ion battery pack to achieve around one hour of battery life before recharge, equivalent to three complete therapy sessions. 
The nRF52832 SoC was recommended to us very early on by a hardware engineer as a SoC that would be easy to develop with
Dan Evans, RecoverX
Nordic’s nRF52832 SoC combines a powerful 64MHz, 32-bit Arm® Cortex® M4 processor with floating point unit (FPU), with a 2.4GHz multiprotocol radio (supporting Bluetooth 5.2, ANT™, and proprietary 2.4GHz RF protocol software) featuring -96-dB RX sensitivity, with 512kB Flash memory and 64kB RAM. The SoC is supplied with Nordic’s S132 SoftDevice, a Bluetooth 5.2-certifed RF software protocol stack for building advanced Bluetooth LE applications. The S132 SoftDevice features Central, Peripheral, Broadcaster and Observer Bluetooth LE roles, and supports up to twenty connections. Nordic’s unique software architecture includes a clear separation between the RF protocol software and RecoverX’s application code. This simplifies development, and ensures the SoftDevice doesn’t get corrupted when developing, compiling, testing, and verifying application code. 


Simplifying development

“The nRF52832 SoC was recommended to us very early on by a hardware engineer as a SoC that would be easy to develop with,” says Dan Evans, Co-founder and CTO of RecoverX. “We were drawn to Nordic’s long history and good reputation. Making a hardware device is extremely difficult so we did not want to try anything new or make anything more difficult for us than it needed to be, so we chose a reliable company and product that has a mature community.
“Nordic’s SDK [Software Development Kit] examples were extremely helpful for developing our application code, while we have also enjoyed Nordic’s large support system for firmware development.”