Bluetooth LE sensor provides detailed analysis of musical instrument activity

Nordic Semiconductor today announces that Washington, U.S.-based technology company TraqFreq has selected Nordic’s nRF52832 Bluetooth® 5.2/Bluetooth Low Energy (Bluetooth LE) general-purpose multiprotocol System-on-Chip (SoC) to provide the processing power and wireless connectivity for its ‘TraqFreq’ musical instrument activity tracker. Designed for musicians at any skill level including music teachers and students, TraqFreq allows the user to track and evaluate their playing behavior.  

The 32 by 11mm form factor device can be attached either inside or outside an instrument such as acoustic, and electric guitars, violins, cellos, saxophones, trumpets and pianos. Alongside the Nordic SoC, the TraqFreq device integrates an accelerometer and temperature and humidity sensors, enabling the solution to monitor both climate conditions and playing time of a musical instrument. As certain instruments can be sensitive to temperature and humidity—and can be damaged if they are exposed to extremes for too long—monitoring temperature can assist in extending their lifespan. By measuring playing time data, the device can also determine the lifespan of instrument consumables such as strings and bows, for example.  

Ample computational power

The nRF52832 SoC’s 64MHz, 32-bit Arm® Cortex® M4 processor with floating point unit (FPU) and generous 512kB Flash and 64kB RAM, provides ample computational power to supervise the sensors, as well as store up to 30 days of data if required. The SoC’s Bluetooth LE connectivity enables the data to be wirelessly relayed to a Bluetooth 4.0 (and later) smartphone or tablet, where from the iOS and Android ‘TraqFreq’ app, the user can review playing time and climate information, and when it is recommended, replace instrument consumables. 

TraqFreq is powered by a single CR2450 coin cell battery, and with two to three hours of playing time a day, can provide 10-12 months battery life between replacement, thanks in part to the ultra low power characteristics of the Nordic SoC. The nRF52832 has been engineered to minimize power consumption with features such as the 2.4GHz radio’s 5.5mA peak RX/TX currents and a fully-automatic power management system that reduces power consumption by up to 80 percent compared with Nordic’s nRF51 Series SoCs. 

Nordic’s nRF52832 multiprotocol SoC combines the Arm Cortex M4 processor with a 2.4GHz multiprotocol radio (supporting Bluetooth 5.2, ANT™, and proprietary 2.4GHz RF protocol software). The nRF Connect SDK [Software Development Kit] is recommended for nRF52832 software development. The nRF Connect SDK integrates the Zephyr RTOS, supports applications using Bluetooth LE, Bluetooth mesh and Thread, and includes examples, Bluetooth LE profiles and driver support for all peripherals. The SDK also includes a migration of Nordic’s Bluetooth SoftDevice Controller from the company’s proven SoftDevices used with the nRF52 Series. The nRF5 SDK can still be used for development with Nordic’s S132 SoftDevice, a Bluetooth 5-certifed RF software protocol stack for building advanced Bluetooth LE applications. 

Large Flash memory

“Nordic’s nRF52832 SoC was the perfect fit for our device,” says Shannon Pahl, Co-Founder of TraqFreq. “With music signal processing we need to process high ODR [Output Data Rate] sensor data, and require a large Flash memory to store climate and playing data. Nordic’s SoC made both possible.  

“Battery life was also critical in choosing a chip. We would not have released this product if it required the user to replace the battery every few months.” 

• About TraqFreq
• About nRF52832
• About Nordic Semiconductor