Getting the rssi value (on peripheral side) of a phone connected to the peripheral

RE: Getting the rssi value (on peripheral side) of a phone connected to the peripheral

MartinBL — Thu, 13 Sep 2018 13:12:24 GMT

A colleague of mine will help you out in the other thread.

RE: Getting the rssi value (on peripheral side) of a phone connected to the peripheral

GK — Thu, 13 Sep 2018 08:54:05 GMT

HI Martin, Thank you for your time and reply.

Yes I got the help. But still I am facing issues with the implementation of whitelist.

I have referred https://devzone.nordicsemi.com/f/nordic-q-a/18608/whitelisting-in-s132-v3-for-advertising-filter-policy/71827#71827 this also.

But still I am facing some issues.

I have posted query here .

https://devzone.nordicsemi.com/f/nordic-q-a/38488/issue-in-implementing-whitelist

Please give me some guidance if possible.

Thanking you in advance,

with regards,

Geetha

RE: Getting the rssi value (on peripheral side) of a phone connected to the peripheral

MartinBL — Thu, 13 Sep 2018 08:16:59 GMT

Hi,

In the BLE_GAP_EVT_RSSI_CHANGED case, p_ble_evt->evt.gap_evt.params.connected.peer_addr doesn't contain the data you think it is.

Please have a look at the `ble_gap_evt_t` structure and note how unions are used to store different information for different events, but in the same place in memory:

/**@brief GAP event structure. */ /**< Connection Handle on which event occurred. */ /**< union alternative identified by evt_id in enclosing struct. */ connected; /**< Connected Event Parameters. */ disconnected; /**< Disconnected Event Parameters. */ conn_param_update; /**< Connection Parameter Update Parameters. */ sec_params_request; /**< Security Parameters Request Event Parameters. */ sec_info_request; /**< Security Information Request Event Parameters. */ passkey_display; /**< Passkey Display Event Parameters. */ key_pressed; /**< Key Pressed Event Parameters. */ auth_key_request; /**< Authentication Key Request Event Parameters. */ lesc_dhkey_request; /**< LE Secure Connections DHKey calculation request. */ auth_status; /**< Authentication Status Event Parameters. */ conn_sec_update; /**< Connection Security Update Event Parameters. */ timeout; /**< Timeout Event Parameters. */ rssi_changed; /**< RSSI Event Parameters. */ adv_report; /**< Advertising Report Event Parameters. */ sec_request; /**< Security Request Event Parameters. */ conn_param_update_request; /**< Connection Parameter Update Parameters. */ scan_req_report; /**< Scan Request Report Parameters. */ phy_update_request; /**< PHY Update Request Event Parameters. */ phy_update; /**< PHY Update Parameters. */ data_length_update_request; /**< Data Length Update Request Event Parameters. */ data_length_update; /**< Data Length Update Event Parameters. */ /**< Event Parameters. */

This means that on a BLE_GAP_EVT_RSSI_CHANGED event, you cannot expect to find information about a BLE_GAP_EVT_CONNECTED in the p_ble_evt variable. The value at p_ble_evt->evt.gap_evt.params.connected.peer_addr is old at best, and total garbage at worst.

Regarding how to get RSSI and peer address from nearby phones I see that you got help on that here: https://devzone.nordicsemi.com/f/nordic-q-a/38148/connecting-the-ble-device-to-a-phone-app-with-highest-signal-strength/

RE: Getting the rssi value (on peripheral side) of a phone connected to the peripheral

GK — Wed, 12 Sep 2018 07:34:12 GMT

I am trying to implement the following scenario.

One periheral

Multiple phones.

Each phone tries to connect to the peripheral.

I want to connect to the one with highest rssi value.

I was planning to do the following

Once the advertising start , the initial 30 seconds I will use to collect the addresses of the phones (whoever tries to connect to the peripheral) and their rssi values. (here i will do connect-disconnect operation to get the details, for 30 secs(for example i am taking this value))

Then sort it and select the one with highest rssi.

After 30 seconds when everyone tries to connect I will check the address of each one and will allow only the one whose adddress match with the selected one ( which has the highest rssi value).

Will you please tell me if there is any other ways to tackle this scenario(if my approach is not good)?

RE: Getting the rssi value (on peripheral side) of a phone connected to the peripheral

awneil — Wed, 12 Sep 2018 07:26:08 GMT

Why do you need to know the peer address?

A BLE (non mesh) connection is only ever 1-to-1 - so there is no need to distinguish different peers in the connection?