switching beacon mode to pairing/connectable mode without module reset nRF52832

[harshg]

Hello,

I am a newbie and need some help deciding the path to perform the following requirement. Any help is appreciated.

 Requirement:

I have Rigado BMD-350 module currently advertising in beacon mode. 

I would like to switch from beacon mode to connectable BLE mode (pairing mode) when a cell phone comes close to it and would like to connect.

Once connection is established, I would like to receive data from the cell phone and store it. and then close the connection and move back to beacon mode.

BMD-350 comes with BMDware which is out of date and is no longer supported. Instead, I would like to write open source code for nrf52832 (nrf module in BMD-350) to achieve the above requirement.

What is the best path to go about this requirement. Also which soft device is recommended?

Thank you

[Einar Thorsrud]

Hi,

How do you intend to detect that the phone is close? The way I see it, there are (at least) two possible approaches:

1) Always advertise non-connectable, but also scan in between. A phone with a custom app could advertise, and when your nRF detects the advertisement packets it can switch to connectable. This has the downside that scanning is typically less power-efficient, and a custom app is required (may not be an issue).

2) Either alway advertise connectable (should not be a problem), or alternate between advertising non-connectable most of the time and connectable some of the time. Then the phone could connect when the nRF advertises in connectable mode.

Since you are working with an nRF52832, I recomend you use the lastest nRF5 SDK (currently version 16, and SoftDevice S132 version 7.0.1).

[harshg]

Hi,

Thank you for your prompt reply.

If I would like to go with option 2, my question is in beacon mode can I always advertise connectable? 

Also, when the phone would like to connect, what is the best way to pair them so that it connects to one phone and not multiple phones at the same time

I will look in to the recommended version and SoftDevice. Thank you

[Einar Thorsrud]

Hi,

There is no problem always advertising connectable (unless your specific use case requires the advertisements to be non-connectable).

If you want to limit the number of connected phones to maximum one at a time, you can advertise connectable when no phones are connected, and as non-connectable when a phone is connected. If you want to make sure that just one phone is allowed to connect, you can allow a single peer to bond, and advertise using a whitelist after that (whitelist meaning that only the whitelisted peer is allowed to connect). Note that in that case, you need a way to reset the bonding, so that you can explicitly allow a new peer to connect when needed.

[harshg]

Hi Einar,

Spend sometime to go through the SDK examples and learn more abt the GATT architecture.

I am trying the following

make adv connectable in beacon.. adding ble_nus service to it. Once Mobile connects send data to ble_nus service.

In current code, the adv parameter is set to Non_Connectable_non_Scannable

// Initialize advertising parameters (used when starting advertising).
	memset(&m_adv_params, 0, sizeof(m_adv_params));

	m_adv_params.properties.type = BLE_GAP_ADV_TYPE_NONCONNECTABLE_NONSCANNABLE_UNDIRECTED;  
	m_adv_params.p_peer_addr     = NULL; // Undirected advertisement.
	m_adv_params.filter_policy   = BLE_GAP_ADV_FP_ANY;
	m_adv_params.interval        = MSEC_TO_UNITS(MAX_ADV_INTERVAL, UNIT_0_625_MS); // Will use timer to dictate interval due to interleaving
	m_adv_params.duration        = IB_NON_CONN_ADV_TIMEOUT;
	m_adv_params.primary_phy     = BLE_GAP_PHY_1MBPS;

I changed it as follows. I am not able to connect to the device using nRF Connect. I receive a device disconnected error. Please direct right way of doing this

m_adv_params.properties.type = BLE_GAP_ADV_TYPE_CONNECTABLE_SCANNABLE_UNDIRECTED; 

[harshg]

ERROR LOG IN NRF Connect

15:35:24.342

Connecting to device

15:35:24.574

Connected to device F5:C9:78:CF:4D:74

15:35:28.470

Disconnected from device F5:C9:78:CF:4D:74, reason: BLE_HCI_CONNECTION_TIMEOUT