how to send characteristic value to another nrf51DK board

[norin saiyed]

Hi, I'm using NRF51 DK board and i am following characteristic tutorial available. I am able to send temperature value over Bluetooth by using light blue app.. Instead of using this application now i want to send this data over Bluetooth to another nrf51 DK board.

Thanks

[endnode]

Then one of the boards must be Master (GAP Central) and second Slave (GAP Peripheral) In your case of LightBlu is your iPhone most probably Master so you need to achieve the same behavior in nRF5x FW to see the same. Have you ever run some nRF5 SDK examples against each other like Nordic BLE UART Service (NUS)? There are both Peripheral (+ GATT Server) and Central (+ GATT Client) examples in the SDK so I would start with them...

[norin saiyed]

Hi, I have tried ble_app_uart_c example as a central device.. but not able to get the response. How should i get the values send by a peripheral device on my central device???

[endnode]

You will firstly need to have matching "profiles" meaning good opposite GAP and GATT roles and on GATT layer Server must expose right Service(s) and Characteristic(s) with the right UUID and on Client side your app must be looking for the same. Finally on top of these GATT objects you need to define "protocol" (it can be as simple as "pass the data stream over without any structure so just raw byte stream") and implement on both sides. Only then devices will work together. But this is like for any other machine in this universe, right? If you want to talk to it, you need to use correct language...

[norin saiyed]

how do i read notification string send by a peripheral device with ble_app_uart_c example..I have configured proper uuid for both peripheral and central

[endnode]

You don't read it, you will receive it as asynchronous event. If you use event handler directly on top of Soft Device then you will see BLE_GATTC_EVT_HVX coming (note that this can change depending on Soft Device version you use so consult proper API spec). Then in event data structure you can see what arrived. However if you use some modules to manage certain SoftDevice events then this might be hidden from you in their callback functions or some internal state machines...