samples/bluetooth/bthome_sensor_template/src/main.c

/*
 * Copyright (c) 2023 Nordic Semiconductor ASA
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <zephyr/bluetooth/bluetooth.h>
#include <zephyr/bluetooth/uuid.h>

#define SERVICE_DATA_LEN        9
#define SERVICE_UUID            0xfcd2      /* BTHome service UUID */
#define IDX_TEMPL               4           /* Index of lo byte of temp in service data*/
#define IDX_TEMPH               5           /* Index of hi byte of temp in service data*/

#define ADV_PARAM BT_LE_ADV_PARAM(BT_LE_ADV_OPT_USE_IDENTITY, \
				  BT_GAP_ADV_SLOW_INT_MIN, \
				  BT_GAP_ADV_SLOW_INT_MAX, NULL)


static uint8_t service_data[SERVICE_DATA_LEN] = {
	BT_UUID_16_ENCODE(SERVICE_UUID),
	0x40,
	0x02,	/* Temperature */
	0xc4,	/* Low byte */
	0x00,   /* High byte */
	0x03,	/* Humidity */
	0xbf,	/* 50.55%  low byte*/
	0x13,   /* 50.55%  high byte*/
};

static struct bt_data ad[] = {
	BT_DATA_BYTES(BT_DATA_FLAGS, BT_LE_AD_GENERAL | BT_LE_AD_NO_BREDR),
	BT_DATA(BT_DATA_NAME_COMPLETE, CONFIG_BT_DEVICE_NAME, sizeof(CONFIG_BT_DEVICE_NAME) - 1),
	BT_DATA(BT_DATA_SVC_DATA16, service_data, ARRAY_SIZE(service_data))
};

static void bt_ready(int err)
{
	if (err) {
		printk("Bluetooth init failed (err %d)\n", err);
		return;
	}

	printk("Bluetooth initialized\n");

	/* Start advertising */
	err = bt_le_adv_start(ADV_PARAM, ad, ARRAY_SIZE(ad), NULL, 0);
	if (err) {
		printk("Advertising failed to start (err %d)\n", err);
		return;
	}
}

int main(void)
{
	int err;
	int temp = 0;

	printk("Starting BTHome sensor template\n");

	/* Initialize the Bluetooth Subsystem */
	err = bt_enable(bt_ready);
	if (err) {
		printk("Bluetooth init failed (err %d)\n", err);
		return 0;
	}

	for (;;) {
		/* Simulate temperature from 0C to 25C */
		service_data[IDX_TEMPH] = (temp * 100) >> 8;
		service_data[IDX_TEMPL] = (temp * 100) & 0xff;
		if (temp++ == 25) {
			temp = 0;
		}
		err = bt_le_adv_update_data(ad, ARRAY_SIZE(ad), NULL, 0);
		if (err) {
			printk("Failed to update advertising data (err %d)\n", err);
		}
		k_sleep(K_MSEC(BT_GAP_ADV_SLOW_INT_MIN));
	}
	return 0;
}