Do i need to make a service to work with a few received bytes from an advertising packet?

[GeorgeM]

Hi all.

Just wondering if i need to go through the tutorials on making a service if i just want to read a few bytes in an advertising beacon.

I'm a little lost on figuring out what function i need to use or what library looks for a particular device and then getting that devices advertising manufacturer data into memory to work with.

I'd just like to have two devices constantly advertising and constantly scanning and then updating a central with the connection details. similar to a beacon but they may need to connect and transfer data in the future.

[Kenneth]

Hi,

First you should go through a BLE tutorial, like this:
https://devzone.nordicsemi.com/tutorials/b/getting-started/posts/introduction-to-bluetooth-low-energy-and-ble-devel 

Then it is a good idea to go through the Getting Started in the SDK:
http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.sdk5.v15.0.0/nrf51_getting_started.html?cp=4_0_0_1 

In specific look at the BLE libraries (such as advertisment module):
http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.sdk5.v15.0.0/lib_ble.html?cp=4_0_0_3_2 

Then finally you can take an example from the SDK and modify it to your needs, I think the best start would be the BLE blinky (or BLE uart):
(peripheral) \nRF5_SDK_15.0.0_a53641a\examples\ble_peripheral\ble_app_blinky
(central) \nRF5_SDK_15.0.0_a53641a\examples\ble_central\ble_app_blinky_c
(doc) http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.sdk5.v15.0.0/examples_ble.html?cp=4_0_0_4_1 

Typically I recommend to establish a connection as fast as possible, this in most cases ensure the lowest power and latency, and best security and throughput. Using advertisement packet to exchange data is not really a good option, advertisement should only be used to establish a connection.

Best regards,
Kenneth

 

[GeorgeM]

great thanks,

My thought process is to modify the ble uart example to allow constant advertising and constant scanning, waiting for a specific device within rssi value then establish connection, transfer data, ,maybe set a flag to connect the other device right after, disconnect and have the other device scan this advertising data, connect, send data, and disconnect. all while still keeping the phone uart connection alive?

Right now im having trouble writing out data to the ble uart phone, using ble_nus_string_send().

It requires an array to send a string in using the variable type uint8_t * ?

I dont have a lot of experience with uint8_t * types and the infromation im getting seems to be that this is a pointer variable?

How would I send a text string of characters through this function? sorry, im a little lost