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!