how to beacon between Smart mobile and NRF51 detect distance

[tran duc tien]

I am developing a beacon-related project, my nrf51 device needs to play beacon. Beacon will determine the distance from NR51-> Smartphone. If distance = distance I give, I will perform some action. So how to with only nrf51, only 1 smartphone can recognize beacon. and when the distance is known, where will the nrf51 interrupt occur?

Thanks!

Best regards,

Tienpjo

[Simonr]

Hi Tienpjo

The nRF51 series does not support an accurate way of measuring the distance between a beacon and a phone. You can use the RSSI value of the last received packet in a BLE event as a rough estimate of how far away this is by using the RSSI get sample, but I'm afraid this isn't a great way of measuring the distance.

In order to accurately measure distance, you'll either have to triangulate the distance from your phone to multiple nodes in a Mesh network, or use the Bluetooth 5.1 direction finding (which phones don't support as of yet) and only the nRF52811 and nRF52833 support that from our side. 

Best regards,

Simon

[tran duc tien]

In fact, my project doesn't need RSSI. the purpose is to determine the connection of the phone and nrf51, if it is connected, I will do something, if it is not connected I will do something, just like that, I have can create beacons but I don't know how to check the connection between them? Are there any examples similar to it?
thank you!

[Simonr]

Hi

So maybe something like the ble_app_proximity example is what you're looking for? It alerts the user when connected devices are too far apart and can, for example, use the battery service to transmit its battery level while connected.

Best regards,

SImon