How to change the value of the Button characteristic in ble_app_blinky example?

[Diego Garcia]

Hello there

I'm having some fun with the ble_app_blinky example, and I was just wondering if it is possible to change the value that the central receives in the Button characteristic, and change the "Button pressed" and "Button Released" messages for a numeric value, like "1" and "0".
Thanks in advance!

[ovrebekk]

Hi Diego

If I understand you correctly, you just want to send a different 1 byte value than the ones used in the example?

The button characteristic is updated by calling the ble_lbs_on_button_change(uint16_t conn_handle, ble_lbs_t * p_lbs, uint8_t button_state) function, and you can set the button_state value to any 8-bit value that you want, so this should not be a problem. 

If you want to extend the button characteristic to accept more than 8-bits of data then you will have to make some changes to the service functions, but then I would suggest using the ble_app_uart example instead.  

Best regards
Torbjørn

[Diego Garcia]

Exactly, that byte is the one that I want to change, I'm not pretending to deal with more than 8-bits per message.

I thought that "Button Pressed" and "Button Released" were two messages stored into two string variables, but it seems that "button_state" is the responsible of sending this values, I'm I right?

[ovrebekk]

Hi Diego

The "Button pressed" and "Button released" strings are just coded into the app. The actual values sent are 0 and 1. 

In other words you have to change these strings in the app source code, you don't have to make any changes to the ble_app_blinky code running on the nRF52. 

If you want to build your own mobile app based on the blinky example I would suggest using the dedicated blinky app source, which is a lot simpler than the nRF Connect app. 

Available for Android here, and iOS here. 

Best regards
Torbjørn

[Diego Garcia]

That's exactly what I was looking for!
Thank you a lot, Torbjørn!

[ovrebekk]

Happy to help Diego, best of luck with your project