How can you set a TI SensorTag to collect data for later retrieval?

Question

I'm working with a TI SensorTag, and I want it to be able to store the data when my phone is not in range to connect via Bluetooth LE. Currently, the sensor only transmits data when the a device is within wireless range.

By accessing the firmware on the SensorTag, it seems like it should be possible to make it store data even when the phone is not in range and then transmit it when a device becomes available. I'm using an iPhone, accessing it using their example code. I can also use Android code, if someone thinks that would work better.

Is it possible to tell the firmware to log this data locally? If so, what commands need to be transmitted over Bluetooth LE? If not, can the firmware be modified to support this?

Answer 1

I had the same issue and wanted to log data when the iPhone is not connected. I resolved this by modifying the SensorTag firmware to incorporate data recording. Essentially I implemented a new service for logging with an extra set of characteristics (like start/stop, reset, log interval, read start, read end, data).

However I tell you, there is quite some modifications and testing required for such implementation. You also need the IAR Compiler and SDK from TI to get started. I implemented temperature and humidity logging only. I was not interested in the other sensors data.