Mesh sensor cadence

[toni95]

Hi everyone,

I am planning to use the cadence/publish interval property within a mesh network. I can not find any examples on how to use it. I know I can set it in the nrf mesh app but I would like to set the cadence in my implementation (like by clicking a button on the nrf52840DK). The sensor observer should be able to call the set function to set the cadence on a sensor server. Also the sensor observer should get some information about the cadence from the sensor server. Can anyone share some code on how to do it?

Best,

Toni

[toni95]

Hi Hieu,

I can confirm that I always configure the Sensor Server Setup models to receive from the Sensor Client.

Best,

Toni

[Hieu]

Hi Toni,

Just letting you know that I am still looking into this. I tried giving the non-blocking method but met almost similar issues too.

I will keep you updated.

Best,

Hieu

[Hieu]

Hi Toni,

Thank you for your patience. I got things to work in non-blocking mode today.

Here is how I modified the Sensor Client's model_handler.c.

static void sensor_cli_cadence_cb(struct bt_mesh_sensor_cli *cli,
                struct bt_mesh_msg_ctx *ctx,
                const struct bt_mesh_sensor_type *sensor,
                const struct bt_mesh_sensor_cadence_status *cadence)
{
    printk("Cadence for sensor with ID 0x%04x:\n", sensor->id);
    printk("\tFast cadence period: %d\n", cadence->fast_period_div);
    printk("\tMin int: %d\n", cadence->min_int);
}


static const struct bt_mesh_sensor_cli_handlers bt_mesh_sensor_cli_handlers = {
	.data = sensor_cli_data_cb,
	.series_entry = sensor_cli_series_entry_cb,
	.setting_status = sensor_cli_setting_status_cb,
	.sensor = sensor_cli_desc_cb,
	.cadence = sensor_cli_cadence_cb,
};


static void button_handler_cb(uint32_t pressed, uint32_t changed)
{
	...
	// Cadence SET --------------------
	if (pressed & changed & BIT(0)) {
		struct bt_mesh_sensor_value delta_up;
		struct bt_mesh_sensor_value delta_down;
		struct bt_mesh_sensor_value range_low;
		struct bt_mesh_sensor_value range_high;

		// NOTEs: Here, I directly used the sensor type, but you can also use bt_mesh_sensor_type_get to find the correct sensor type.
		// I also used a value-based delta (using the same format as range), rather than percentage-based (where you'd need bt_mesh_sensor_format_percentage_delta_trigger)
		bt_mesh_sensor_value_from_micro(bt_mesh_sensor_present_amb_light_level.channels[0].format,
						1*1000000LL, &delta_up);
		bt_mesh_sensor_value_from_micro(bt_mesh_sensor_present_amb_light_level.channels[0].format,
						1*1000000LL, &delta_down);
		bt_mesh_sensor_value_from_micro(bt_mesh_sensor_present_amb_light_level.channels[0].format,
						1*1000000LL, &range_low);
		bt_mesh_sensor_value_from_micro(bt_mesh_sensor_present_amb_light_level.channels[0].format,
						1*1000000LL, &range_high);
		struct bt_mesh_sensor_cadence_status cadence = {
			.fast_period_div = 1,
			.min_int = 1,
			.threshold = {
				.deltas = {
					.up = delta_up,
					.down = delta_down
				},
				.range = {
					.cadence = BT_MESH_SENSOR_CADENCE_NORMAL,
					.low = range_low,
					.high = range_high
				}
			}
		};

		err = bt_mesh_sensor_cli_cadence_set(&sensor_cli, NULL,
				&bt_mesh_sensor_present_amb_light_level,
				&cadence,
				NULL);
	}

	// Cadence GET --------------------
	if (pressed & changed & BIT(1)) {
		err = bt_mesh_sensor_cli_cadence_get(&sensor_cli, NULL, 
							&bt_mesh_sensor_present_amb_light_level, 
							NULL);
							// &rsp);
		printk("Non-blocking bt_mesh_sensor_cli_cadence_get err = %d\n", err);
	}
	...
}

A couple of pitfalls I found along the way are:

• While configuring Cadence, only the Element that is being configured should subscribe to Sensor Client's messages.
  Otherwise, the other Elements will also receive the same message. This can cause some puzzling logs.
• There can be some incorrect warning about invalid key and invalid address on the Server side if you don't configure the other Elements to also subscribe to Sensor Client's message. 
  This is a bug, but the system behavior is otherwise correct. They will be fixed. For now, please ignore them.

Best,

Hieu