diff --git a/bin/.battery-warn b/bin/.battery-warn
new file mode 100755
index 0000000..6a22f57
--- /dev/null
+++ b/bin/.battery-warn
@@ -0,0 +1,197 @@
+#!/usr/bin/env python
+# SPDX-License-Identifier: CC0-1.0
+# Copyright © 2021 mpan; <https://mpan.pl/>; CC0 1.0 (THIS SCRIPT!)
+# Context: <https://bbs.archlinux.org/viewtopic.php?id=269453>
+# Reference: https://github.com/wogscpar/upower-python
+
+# -*- encoding: utf-8 -*-
+# @File   : .battery-warn
+# @Time   : 2025/12/29 00:32:53
+# @Author : SilverAg.L
+
+# bash pipeline was still too complicated.
+# Dependencies (pacman): python-dbus, libnotify, pipewire-audio
+
+import dbus
+
+from os import getenv
+from subprocess import run as start_process
+
+# region config
+AUD_OUT_EMB = (  # my laptop embedded speaker
+    "alsa_output.pci-0000_00_1f"
+    ".3-platform-skl_hda_dsp_generic.HiFi__Speaker__sink"
+)
+# better searched by editor like VSCode.
+AUD_FILE = "~/.local/share/.low_power.wav".replace("~", getenv("HOME"), 1)
+# endregion config
+
+
+class UPowerManager():
+    def __init__(self):
+        self.UPOWER_NAME = "org.freedesktop.UPower"
+        self.UPOWER_PATH = "/org/freedesktop/UPower"
+
+        self.DBUS_PROPERTIES = "org.freedesktop.DBus.Properties"
+        self.bus = dbus.SystemBus()
+
+    def __upower(self, subpath=None, *, interface=None):
+        if not subpath:
+            subpath = ""
+        upower_proxy = self.bus.get_object(
+            self.UPOWER_NAME,
+            self.UPOWER_PATH + subpath
+        )
+        if interface is None:
+            interface = self.UPOWER_NAME
+        return dbus.Interface(upower_proxy, interface)
+
+    def __battery(self, battery):
+        battery_proxy = self.bus.get_object(self.UPOWER_NAME, battery)
+        return dbus.Interface(battery_proxy, self.DBUS_PROPERTIES)
+
+    def detect_devices(self):
+        return self.__upower().EnumerateDevices()
+
+    def get_display_device(self):
+        return self.__upower().GetDisplayDevice()
+
+    def get_critical_action(self):
+        return self.__upower().GetCriticalAction()
+
+    def get_device_percentage(self, battery):
+        return self.__battery(battery).Get(
+            self.UPOWER_NAME + ".Device", "Percentage")
+
+    def get_full_device_information(self, battery):
+        def get_property(prop_name):
+            return self.__battery(battery).Get(
+                self.UPOWER_NAME + ".Device", prop_name)
+
+        return {
+            'HasHistory': get_property("HasHistory"),
+            'HasStatistics': get_property("HasStatistics"),
+            'IsPresent': get_property("IsPresent"),
+            'IsRechargeable': get_property("IsRechargeable"),
+            'Online': get_property("Online"),
+            'PowerSupply': get_property("PowerSupply"),
+            'Capacity': get_property("Capacity"),
+            'Energy': get_property("Energy"),
+            'EnergyEmpty': get_property("EnergyEmpty"),
+            'EnergyFull': get_property("EnergyFull"),
+            'EnergyFullDesign': get_property("EnergyFullDesign"),
+            'EnergyRate': get_property("EnergyRate"),
+            'Luminosity': get_property("Luminosity"),
+            'Percentage': get_property("Percentage"),
+            'Temperature': get_property("Temperature"),
+            'Voltage': get_property("Voltage"),
+            'TimeToEmpty': get_property("TimeToEmpty"),
+            'TimeToFull': get_property("TimeToFull"),
+            'IconName': get_property("IconName"),
+            'Model': get_property("Model"),
+            'NativePath': get_property("NativePath"),
+            'Serial': get_property("Serial"),
+            'Vendor': get_property("Vendor"),
+            'State': get_property("State"),
+            'Technology': get_property("Technology"),
+            'Type': get_property("Type"),
+            'WarningLevel': get_property("WarningLevel"),
+            'UpdateTime': get_property("UpdateTime")
+        }
+
+    def is_lid_present(self):
+        return bool(self.__upower(interface=self.DBUS_PROPERTIES).Get(
+            self.UPOWER_NAME, 'LidIsPresent'))
+
+    def is_lid_closed(self):
+        return bool(self.__upower(interface=self.DBUS_PROPERTIES).Get(
+            self.UPOWER_NAME, 'LidIsClosed'))
+
+    def on_battery(self):
+        return bool(self.__upower(interface=self.DBUS_PROPERTIES).Get(
+            self.UPOWER_NAME, 'OnBattery'))
+
+    def has_wakeup_capabilities(self):
+        return bool(self.__upower(
+            "/Wakeups",
+            interface=self.DBUS_PROPERTIES
+        ).Get(self.UPOWER_NAME + '.Wakeups', 'HasCapability'))
+
+    def get_wakeups_data(self):
+        return self.__upower(
+            "/Wakeups",
+            interface=self.UPOWER_NAME + '.Wakeups'
+        ).GetData()
+
+    def get_wakeups_total(self):
+        return self.__upower(
+            "/Wakeups",
+            interface=self.UPOWER_NAME + '.Wakeups'
+        ).GetTotal()
+
+    def is_loading(self, battery):
+        state = int(self.__battery(battery).Get(
+            self.UPOWER_NAME + ".Device", "State"))
+
+        return state == 1
+
+    def get_state(self, battery):
+        state = int(self.__battery(battery).Get(
+            self.UPOWER_NAME + ".Device", "State"))
+
+        return {
+            0: "Unknown",
+            1: "Loading",
+            2: "Discharging",
+            3: "Empty",
+            4: "Fully charged",
+            5: "Pending charge",
+            6: "Pending discharge"
+        }.get(state, "Unknown")
+
+
+def push_notification(title, message, timeout=10000):
+    BUS_NAME = "org.freedesktop.Notifications"
+    OBJECT_PATH = "/org/freedesktop/Notifications"
+    INTERFACE = BUS_NAME
+
+    notify = dbus.Interface(
+        dbus.SessionBus().get_object(BUS_NAME, OBJECT_PATH),
+        INTERFACE
+    )
+    notify.Notify(
+        "battery-warn-script",  # app_name
+        0,                      # replaces_id
+        "",                     # app_icon
+        title,                  # summary
+        message,                # body
+        [],                     # actions
+        {},                     # hints
+        timeout                 # expire_timeout
+    )
+
+
+if __name__ == "__main__":
+    upowr = UPowerManager()
+    if not upowr.on_battery():
+        exit(0)
+
+    devPaths = upowr.detect_devices()
+    low_power_detected = False
+    for devPath in devPaths:
+        info = upowr.get_full_device_information(devPath)
+        if info['Type'] != 2:  # 2 means battery
+            continue
+        # seems waybar visual is 1% lower than actual.
+        if info['Percentage'] < 21:
+            push_notification(
+                "Power Hint",
+                f"{info['NativePath']} is running out. Recharge soon!"
+            )
+            low_power_detected = True
+    if low_power_detected:
+        start_process([
+            "pw-play",
+            f"--target={AUD_OUT_EMB}",
+            AUD_FILE
+        ])
diff --git a/readme.md b/readme.md
index 56daa0f..28b7c9b 100644
--- a/readme.md
+++ b/readme.md
@@ -43,3 +43,6 @@
 
 - `hoyocloud-chromium-userscript.js`顾名思义，用于**在 Chrome 里**（firefox 不需要）游玩米哈游云游戏的油猴脚本。
   参见 [Bilibili 专栏](https://www.bilibili.com/opus/842314310196658193)。
+
+- `bin/.battery-warn`虽说也是自用，但一是配置项并不算敏感，稍微改改`config`段也可以泛用；二是参考文献写得有点啰嗦，我懒得再缝第二遍。
+  个人建议用于**定时任务（cron 或 systemd timer）**。