Movesense Sensor Firmware 2.2 Published – New Features and Improvements
Movesense sensor firmware 2.2 is a major update for the Movesense sensor framework. It brings eight new sensor features, three new or improved sensor firmware sample applications, and fixes 25 bugs from the pervious release 2.1.5. We hope you enjoy the new features and build great new products that take advantage of the new possibilities!
Two simultaneous Bluetooth connections
The leading new feature of the 2.2 release is the possibility to connect two host devices simultaneously to one sensor. A common use case would be using a sensor to transmit heart rate readings to your sports watch and ECG to a phone and store it with the Movesense ECG Recorder app. You can of course also develop your own customized applications for both smart watch and phone to take advantage of the versatile measurement possibilities and programmability of the Movesense sensor.
Enabling the dual BLE connection required implementing other new features on the firmware. You can now fully customize the BLE stack configuration, such as how much memory it uses and the size of data chunks sent over Bluetooth. Further wireless improvements include adjustable BLE connection parameters. They allows you to optimize the connection for speed or battery saving, depending on the amount of data that your solution is transmitting.
Faster data transfer and better memory handling
The new firmware also supports forced data length extension that makes BLE connection much faster. This is needed especially to make Movesense sensor to communicate with Raspberry Pi with the fastest data rate. Another new connection speed related feature is that the sensor now asks by default the fastest communication that the Bluetooth 5 supports, i.e. PHY 2M (2Mbit). With this feature in use, we have seen data transfer speeds up to 101 kB/s with an actual phone and an actual sensor.
Configurable memory size allows you to decide how to use the limited memory of the sensor, for instance, do you prioritize the Bluetooth stack or do you need more resources for running an algorithm on the sensor.’
The 2.2 firmware brings also improvements specific to the newly launched Movesense Flash. The main change is a new Logbook json format to avoid OutOfMemory crash that occurred during mobile library data conversion with some phone models. This change is not backward compatible.
With the new firmware you can now use the EEPROM memory of Movesense Flash. This is practical e.g. for storing configuration parameters needed by the algorithms that are running on the sensor.
Sample apps accelerate development
The ability to implement your own sensor applications quickly is one of the strengths of the Movesense platform. The new firmware comes with new sample applications, allowing you to easily utilize the new features in your own implementations.
The offline_gatt_app demonstrates the use of DataLogger and Logbook services in the sensor firmware. It implements DataLogger backup of the streaming data over extended “gatt_sensordata_app” protocol. The included python client subscribes ECG data at 200 Hz and fetches the stored data in case disconnect happens during operation.
The simple_ecglogger_app simplifies collecting ECG data from non-tech-savvy users. It wakes up the sensor when stud contact is detected, starts ECG logging at 200Hz if the sensor memory is empty, and logs data until the memory is full.
The third sample with new features is the updated gatt_sensordata_app that now offers log fetch support. A sample app with the dual BLE connection will be released soon.