diff --git a/custom_components/xiaomi_home/miot/miot_ev.py b/custom_components/xiaomi_home/miot/miot_ev.py
new file mode 100644
index 0000000..be4e684
--- /dev/null
+++ b/custom_components/xiaomi_home/miot/miot_ev.py
@@ -0,0 +1,324 @@
+# -*- coding: utf-8 -*-
+"""
+Copyright (C) 2024 Xiaomi Corporation.
+
+The ownership and intellectual property rights of Xiaomi Home Assistant
+Integration and related Xiaomi cloud service API interface provided under this
+license, including source code and object code (collectively, "Licensed Work"),
+are owned by Xiaomi. Subject to the terms and conditions of this License, Xiaomi
+hereby grants you a personal, limited, non-exclusive, non-transferable,
+non-sublicensable, and royalty-free license to reproduce, use, modify, and
+distribute the Licensed Work only for your use of Home Assistant for
+non-commercial purposes. For the avoidance of doubt, Xiaomi does not authorize
+you to use the Licensed Work for any other purpose, including but not limited
+to use Licensed Work to develop applications (APP), Web services, and other
+forms of software.
+
+You may reproduce and distribute copies of the Licensed Work, with or without
+modifications, whether in source or object form, provided that you must give
+any other recipients of the Licensed Work a copy of this License and retain all
+copyright and disclaimers.
+
+Xiaomi provides the Licensed Work on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+CONDITIONS OF ANY KIND, either express or implied, including, without
+limitation, any warranties, undertakes, or conditions of TITLE, NO ERROR OR
+OMISSION, CONTINUITY, RELIABILITY, NON-INFRINGEMENT, MERCHANTABILITY, or
+FITNESS FOR A PARTICULAR PURPOSE. In any event, you are solely responsible
+for any direct, indirect, special, incidental, or consequential damages or
+losses arising from the use or inability to use the Licensed Work.
+
+Xiaomi reserves all rights not expressly granted to you in this License.
+Except for the rights expressly granted by Xiaomi under this License, Xiaomi
+does not authorize you in any form to use the trademarks, copyrights, or other
+forms of intellectual property rights of Xiaomi and its affiliates, including,
+without limitation, without obtaining other written permission from Xiaomi, you
+shall not use "Xiaomi", "Mijia" and other words related to Xiaomi or words that
+may make the public associate with Xiaomi in any form to publicize or promote
+the software or hardware devices that use the Licensed Work.
+
+Xiaomi has the right to immediately terminate all your authorization under this
+License in the event:
+1. You assert patent invalidation, litigation, or other claims against patents
+or other intellectual property rights of Xiaomi or its affiliates; or,
+2. You make, have made, manufacture, sell, or offer to sell products that knock
+off Xiaomi or its affiliates' products.
+
+MIoT event loop.
+"""
+import selectors
+import heapq
+import time
+import traceback
+from typing import Callable, TypeVar
+import logging
+import threading
+
+# pylint: disable=relative-beyond-top-level
+from .miot_error import MIoTEvError
+
+_LOGGER = logging.getLogger(__name__)
+
+TimeoutHandle = TypeVar('TimeoutHandle')
+
+
+class MIoTFdHandler:
+    """File descriptor handler."""
+    fd: int
+    read_handler: Callable[[any], None]
+    read_handler_ctx: any
+    write_handler: Callable[[any], None]
+    write_handler_ctx: any
+
+    def __init__(
+            self, fd: int,
+            read_handler: Callable[[any], None] = None,
+            read_handler_ctx: any = None,
+            write_handler: Callable[[any], None] = None,
+            write_handler_ctx: any = None
+    ) -> None:
+        self.fd = fd
+        self.read_handler = read_handler
+        self.read_handler_ctx = read_handler_ctx
+        self.write_handler = write_handler
+        self.write_handler_ctx = write_handler_ctx
+
+
+class MIoTTimeout:
+    """Timeout handler."""
+    key: TimeoutHandle
+    target: int
+    handler: Callable[[any], None]
+    handler_ctx: any
+
+    def __init__(
+            self, key: str = None, target: int = None,
+            handler: Callable[[any], None] = None,
+            handler_ctx: any = None
+    ) -> None:
+        self.key = key
+        self.target = target
+        self.handler = handler
+        self.handler_ctx = handler_ctx
+
+    def __lt__(self, other):
+        return self.target < other.target
+
+
+class MIoTEventLoop:
+    """MIoT event loop."""
+    _poll_fd: selectors.DefaultSelector
+
+    _fd_handlers: dict[str, MIoTFdHandler]
+
+    _timer_heap: list[MIoTTimeout]
+    _timer_handlers: dict[str, MIoTTimeout]
+    _timer_handle_seed: int
+
+    # Label if the current fd handler is freed inside a read handler to
+    # avoid invalid reading.
+    _fd_handler_freed_in_read_handler: bool
+
+    def __init__(self) -> None:
+        self._poll_fd = selectors.DefaultSelector()
+        self._timer_heap = []
+        self._timer_handlers = {}
+        self._timer_handle_seed = 1
+        self._fd_handlers = {}
+        self._fd_handler_freed_in_read_handler = False
+
+    def loop_forever(self) -> None:
+        """Run an event loop in current thread."""
+        next_timeout: int
+        while True:
+            next_timeout = 0
+            # Handle timer
+            now_ms: int = self.__get_monotonic_ms
+            while len(self._timer_heap) > 0:
+                timer: MIoTTimeout = self._timer_heap[0]
+                if timer is None:
+                    break
+                if timer.target <= now_ms:
+                    heapq.heappop(self._timer_heap)
+                    del self._timer_handlers[timer.key]
+                    if timer.handler:
+                        timer.handler(timer.handler_ctx)
+                else:
+                    next_timeout = timer.target-now_ms
+                    break
+            # Are there any files to listen to
+            if next_timeout == 0 and self._fd_handlers:
+                next_timeout = None  # None == infinite
+            # Wait for timers & fds
+            if next_timeout == 0:
+                # Neither timer nor fds exist, exit loop
+                break
+            # Handle fd event
+            events = self._poll_fd.select(
+                timeout=next_timeout/1000.0 if next_timeout else next_timeout)
+            for key, mask in events:
+                fd_handler: MIoTFdHandler = key.data
+                if fd_handler is None:
+                    continue
+                self._fd_handler_freed_in_read_handler = False
+                fd_key = str(id(fd_handler.fd))
+                if fd_key not in self._fd_handlers:
+                    continue
+                if (
+                    mask & selectors.EVENT_READ > 0
+                    and fd_handler.read_handler
+                ):
+                    fd_handler.read_handler(fd_handler.read_handler_ctx)
+                if (
+                    mask & selectors.EVENT_WRITE > 0
+                    and self._fd_handler_freed_in_read_handler is False
+                    and fd_handler.write_handler
+                ):
+                    fd_handler.write_handler(fd_handler.write_handler_ctx)
+
+    def loop_stop(self) -> None:
+        """Stop the event loop."""
+        if self._poll_fd:
+            self._poll_fd.close()
+            self._poll_fd = None
+            self._fd_handlers = {}
+            self._timer_heap = []
+            self._timer_handlers = {}
+
+    def set_timeout(
+        self, timeout_ms: int, handler: Callable[[any], None],
+        handler_ctx: any = None
+    ) -> TimeoutHandle:
+        """Set a timer."""
+        if timeout_ms is None or handler is None:
+            raise MIoTEvError('invalid params')
+        new_timeout: MIoTTimeout = MIoTTimeout()
+        new_timeout.key = self.__get_next_timeout_handle
+        new_timeout.target = self.__get_monotonic_ms + timeout_ms
+        new_timeout.handler = handler
+        new_timeout.handler_ctx = handler_ctx
+        heapq.heappush(self._timer_heap, new_timeout)
+        self._timer_handlers[new_timeout.key] = new_timeout
+        return new_timeout.key
+
+    def clear_timeout(self, timer_key: TimeoutHandle) -> None:
+        """Stop and remove the timer."""
+        if timer_key is None:
+            return
+        timer: MIoTTimeout = self._timer_handlers.pop(timer_key, None)
+        if timer:
+            self._timer_heap = list(self._timer_heap)
+            self._timer_heap.remove(timer)
+            heapq.heapify(self._timer_heap)
+
+    def set_read_handler(
+        self, fd: int, handler: Callable[[any], None], handler_ctx: any = None
+    ) -> bool:
+        """Set a read handler for a file descriptor.
+
+        Returns:
+            bool: True, success. False, failed.
+        """
+        self.__set_handler(
+            fd, is_read=True, handler=handler, handler_ctx=handler_ctx)
+
+    def set_write_handler(
+        self, fd: int, handler: Callable[[any], None], handler_ctx: any = None
+    ) -> bool:
+        """Set a write handler for a file descriptor.
+
+        Returns:
+            bool: True, success. False, failed.
+        """
+        self.__set_handler(
+            fd, is_read=False, handler=handler, handler_ctx=handler_ctx)
+
+    def __set_handler(
+        self, fd, is_read: bool, handler: Callable[[any], None],
+        handler_ctx: any = None
+    ) -> bool:
+        """Set a handler."""
+        if fd is None:
+            raise MIoTEvError('invalid params')
+
+        if not self._poll_fd:
+            raise MIoTEvError('event loop not started')
+
+        fd_key: str = str(id(fd))
+        fd_handler = self._fd_handlers.get(fd_key, None)
+
+        if fd_handler is None:
+            fd_handler = MIoTFdHandler(fd=fd)
+            fd_handler.fd = fd
+            self._fd_handlers[fd_key] = fd_handler
+
+        read_handler_existed = fd_handler.read_handler is not None
+        write_handler_existed = fd_handler.write_handler is not None
+        if is_read is True:
+            fd_handler.read_handler = handler
+            fd_handler.read_handler_ctx = handler_ctx
+        else:
+            fd_handler.write_handler = handler
+            fd_handler.write_handler_ctx = handler_ctx
+
+        if fd_handler.read_handler is None and fd_handler.write_handler is None:
+            # Remove from epoll and map
+            try:
+                self._poll_fd.unregister(fd)
+            except (KeyError, ValueError, OSError) as e:
+                del e
+            self._fd_handlers.pop(fd_key, None)
+            # May be inside a read handler, if not, this has no effect
+            self._fd_handler_freed_in_read_handler = True
+        elif read_handler_existed is False and write_handler_existed is False:
+            # Add to epoll
+            events = 0x0
+            if fd_handler.read_handler:
+                events |= selectors.EVENT_READ
+            if fd_handler.write_handler:
+                events |= selectors.EVENT_WRITE
+            try:
+                self._poll_fd.register(fd, events=events, data=fd_handler)
+            except (KeyError, ValueError, OSError) as e:
+                _LOGGER.error(
+                    '%s, register fd, error, %s, %s, %s, %s, %s',
+                    threading.current_thread().name,
+                    'read' if is_read else 'write',
+                    fd_key, handler, e, traceback.format_exc())
+                self._fd_handlers.pop(fd_key, None)
+                return False
+        elif (
+            read_handler_existed != (fd_handler.read_handler is not None)
+            or write_handler_existed != (fd_handler.write_handler is not None)
+        ):
+            # Modify epoll
+            events = 0x0
+            if fd_handler.read_handler:
+                events |= selectors.EVENT_READ
+            if fd_handler.write_handler:
+                events |= selectors.EVENT_WRITE
+            try:
+                self._poll_fd.modify(fd, events=events, data=fd_handler)
+            except (KeyError, ValueError, OSError) as e:
+                _LOGGER.error(
+                    '%s, modify fd, error, %s, %s, %s, %s, %s',
+                    threading.current_thread().name,
+                    'read' if is_read else 'write',
+                    fd_key, handler, e, traceback.format_exc())
+                self._fd_handlers.pop(fd_key, None)
+                return False
+
+        return True
+
+    @property
+    def __get_next_timeout_handle(self) -> str:
+        # Get next timeout handle, that is not larger than the maximum
+        # value of UINT64 type.
+        self._timer_handle_seed += 1
+        # uint64 max
+        self._timer_handle_seed %= 0xFFFFFFFFFFFFFFFF
+        return str(self._timer_handle_seed)
+
+    @property
+    def __get_monotonic_ms(self) -> int:
+        """Get monotonic ms timestamp."""
+        return int(time.monotonic()*1000)
diff --git a/test/test_ev.py b/test/test_ev.py
new file mode 100644
index 0000000..6353fe8
--- /dev/null
+++ b/test/test_ev.py
@@ -0,0 +1,55 @@
+# -*- coding: utf-8 -*-
+"""Unit test for miot_ev.py."""
+import os
+import pytest
+
+# pylint: disable=import-outside-toplevel, disable=unused-argument
+
+
+@pytest.mark.github
+def test_mev_timer_and_fd():
+    from miot.miot_ev import MIoTEventLoop, TimeoutHandle
+
+    mev = MIoTEventLoop()
+    assert mev
+    event_fd: os.eventfd = os.eventfd(0, os.O_NONBLOCK)
+    assert event_fd
+    timer4: TimeoutHandle = None
+
+    def event_handler(event_fd):
+        value: int = os.eventfd_read(event_fd)
+        if value == 1:
+            mev.clear_timeout(timer4)
+            print('cancel timer4')
+        elif value == 2:
+            print('event write twice in a row')
+        elif value == 3:
+            mev.set_read_handler(event_fd, None, None)
+            os.close(event_fd)
+            event_fd = None
+            print('close event fd')
+
+    def timer1_handler(event_fd):
+        os.eventfd_write(event_fd, 1)
+
+    def timer2_handler(event_fd):
+        os.eventfd_write(event_fd, 1)
+        os.eventfd_write(event_fd, 1)
+
+    def timer3_handler(event_fd):
+        os.eventfd_write(event_fd, 3)
+
+    def timer4_handler(event_fd):
+        raise ValueError('unreachable code')
+
+    mev.set_read_handler(
+        event_fd, event_handler, event_fd)
+
+    mev.set_timeout(500, timer1_handler, event_fd)
+    mev.set_timeout(1000, timer2_handler, event_fd)
+    mev.set_timeout(1500, timer3_handler, event_fd)
+    timer4 = mev.set_timeout(2000, timer4_handler, event_fd)
+
+    mev.loop_forever()
+    # Loop will exit when there are no timers or fd handlers.
+    mev.loop_stop()