Use of scenes in BLE mesh with nrf52840

[stefanogradozzi]

Hi,

I have autoprovisioned and autoconfigured my nrf52840 board (provisioning and configuring are made inside the software and not through external app/provisioner).

In particular, I have configured three couples of switch/led as client/server.

Now I'd like to set some scenes, for example:

• two leds on and one off.
• one led on and two off
• all led on

My goal is to be able to recall one of these scenes 

How can I implement these scenes in the software? Which is the way to memorize them?

And then how can I recall each of them?

Here is my elements definition:

/* ELEMENTS */
static struct bt_mesh_elem elements[] = {
	BT_MESH_ELEM(1,
				 BT_MESH_MODEL_LIST(
					 BT_MESH_MODEL_CFG_SRV,
					 BT_MESH_MODEL_CFG_CLI(&cli_data),
					 BT_MESH_MODEL_HEALTH_SRV(&health_srv, &health_pub),
					 BT_MESH_MODEL_DFD_SRV(&dfd_srv),
					 BT_MESH_MODEL_ONOFF_CLI(&buttons[BUTTON_IDX].client),
					 BT_MESH_MODEL_ONOFF_SRV(&led_ctx[LED_IDX].srv)),
				 BT_MESH_MODEL_LIST(
					 BT_MESH_MODEL_CHAT_CLI(&chat))),
	BT_MESH_ELEM(2,
				 BT_MESH_MODEL_LIST(
					 BT_MESH_MODEL_DFU_SRV(&dfu_srv)),
				 BT_MESH_MODEL_NONE),
	BT_MESH_ELEM(3,
				 BT_MESH_MODEL_LIST(
					 BT_MESH_MODEL_ONOFF_CLI(&buttons[BUTTON_IDX2].client),
					 BT_MESH_MODEL_ONOFF_SRV(&led_ctx[LED_IDX2].srv)),
				 BT_MESH_MODEL_NONE),
	BT_MESH_ELEM(4,
				 BT_MESH_MODEL_LIST(
					 BT_MESH_MODEL_ONOFF_CLI(&buttons[BUTTON_IDX3].client),
					 BT_MESH_MODEL_ONOFF_SRV(&led_ctx[LED_IDX3].srv)),
				 BT_MESH_MODEL_NONE),
};

I hope in your help as always

Best regards

[Elfving]

Hi Stefano and thanks for your patience,

First of all, doing things in regards to provisioning etc in Mesh programmatically is always a bit frowned upon, as having a dedicated provisioner is considered the safer choice. Though I assume you've already been told about this in the past, so I'll leave it at that. 

In order to use scenes you'll have to use scene server models, and eg. using bt_mesh_scene_cli_store() and bt_mesh_scene_cli_recall(). Have a look here.

The best way to learn how this can be done is probably using and testing out the Light dimmer and scene selector sample.

Regards,

Elfving

[stefanogradozzi]

Hi,

Thank you for your information.

I have examined your firmware related to light_ctrl sample and I tried to import in my firmware all the instructions related to scenes. Here is what I did:

• I added CONFIG_BT_MESH_SCENE_SRV=y in my prj.conf
• I added:
  • static struct bt_mesh_scene_srv scene_srv in my model_handler.c
  • BT_MESH_MODEL_SCENE_SRV(&scene_srv), in element list in my model_handler.c

Well, I manage to build correctly my program (0 errors), but after programming the result is that the program does not start (the red led should light on but nothing happens)

Then I verified that if I comment:

 BT_MESH_MODEL_SCENE_SRV(&scene_srv)

the program starts correctly (the red led lights on etc.)

Why this happens?

What have I missed?

I wait for your help

Best regards

[stefanogradozzi]

Hi,

I want to add an information about this problem: I verified serial messages after reset and I found that the following error is signalled:

bt_mesh_scene_srv:Failed to find Generic DTT Server on element

This is why the program does not start

I hope this information can be useful to you to resolve the problem

[Elfving]

Hi, 

Looks like you need a Generic Default Transition Time model on the same element, to handle the transition between scenes, given that you are using a server. There is a bit about this here and here. The light dimmer sample shows the client side.

add a static struct bt_mesh_dtt_srv dtt_srv and a  BT_MESH_MODEL_DTT_SRV(&dtt_srv) to the element list.

Regards,

Elfving

[stefanogradozzi]

Thank you,

with your help now my program starts correctly!

Regards