How to increase data transfer rate for BLE nrf51822 to raspberry pi?

[Husain]

I am working on a project where i need to send sensor values from nrf51822 module to a raspberry pi. The sensor values are received by the nrf using I2C protocol. I am using mbed compiler with the BLE.h and Gap.h libraries. I want to increase the data transfer rate. Currently it sends data at an interval of 150ms. I want to bring this down to 10ms. I tried tweaking parameters for the setAdvertisingInterval() function, but it didnt change the speed at all. Please help.

[ovrebekk]

Hi

I assume you are connected when you want to transfer the data, and in this case it is the connection interval that is critical, not the advertising interval.

The connection interval is typically set by defining a range of acceptable connection intervals, as described in this article:
https://docs.mbed.com/docs/ble-intros/en/latest/Introduction/ConnectionParameters/

The minimum connection interval is 7.5ms, but not all BLE central devices will allow you to use the shortest connection intervals. You might want to consider packing multiple sensor updates into a single packet, to make the data transmission more efficient.

Best regards
Torbjørn

[ovrebekk]

Hi

I think most of the mBed BLE libraries are connection based, including this one.

How many bytes long is each sensor value?
It seems odd that adding multiple values together wouldn't increase overall data rate, unless you are still breaking them up before sending them across the BLE link.

As a general note, you might get better support for mBed specific questions by using the mBed forums. Since mBed is not a Nordic delivery we have limited experience with it.

Best regards