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TaskHandle_t led_task_handle = nullptr; // handle to the task for led blinking
esp_timer_handle_t led_timer_handle = nullptr; // handle to the timer to stop led blinking
const esp_timer_create_args_t led_timer_args = {
	&led_timer_callback, // function to call when timer expires
	(void*) &led_task_handle, // argument to pass to the callback, must be void*
	ESP_TIMER_TASK, // callback is called from timer task
	"led_timer", // timer name, must be a const char*
};
ESP_ERROR_CHECK(esp_timer_create(&led_timer_args, &led_timer_handle)); // create the timer to be used by the led blink function

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if(led_task_handle == nullptr){ // if this is the first time we receive blink we create the task, otherwise we don't do anything because the led task is already running
	xTaskCreate(&led_task, "led_task", 512, &led_task_handle, 5, &led_task_handle); // create task to use onboard led
	ESP_ERROR_CHECK(esp_timer_start_once(led_timer_handle, BLINK_DURATION*1000000)); // start the timer to trigger blink stop (time duration is in microseconds)
	ESP_LOGI(TAG, "LED task started.");
}

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esp_timer_stop(led_timer_handle); // stop the timer from running (no ESP_ERROR_CHECK because we don't know if the timer has ever started)
esp_timer_delete(led_timer_handle); // delete the timer (no ESP_ERROR_CHECK because we don't know if the timer has ever started)
if(led_task_handle != nullptr){ // stop immediately the blink
	vTaskDelete(led_task_handle); // delete led blinking task
	led_task_handle = nullptr; // set back the task handler to nullptr for safety reasons
	turn_off_led(); // this simply sets the onboard LED pin to 0 in order to turn it off
}

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void led_timer_callback(void *param){
	TaskHandle_t *led_task_handle = (TaskHandle_t*)param;
	if(*led_task_handle != nullptr){
		vTaskDelete(*led_task_handle); // delete led blinking task
		*led_task_handle = nullptr; // set back the task handler to nullptr for safety reasons
		turn_off_led(); // this simply sets the onboard LED pin to 0 in order to turn it off
	}
}