Hardware Monitor

Overview

Hardware Monitor is an NVDA global plugin that speaks hardware information collected through Libre Hardware Monitor.

Keyboard Commands

• NVDA+Shift+9: Reports the current CPU temperature and appends GPU temperature when available.
• NVDA+Shift+0: Reports all detected fan speeds, including GPU fan speeds when available. Fans at 0 RPM are ignored.
• NVDA+Shift+-: Reports the current GPU usage and appends VRAM usage when available.

Requirements

• Windows
• NVDA 2024.1 or later
• PawnIO is required for full low-level sensor access

Important Architecture Warning

This add-on is not a pure Python hardware monitor.

It starts LHM_LocalBridge.exe, and that helper process calls LibreHardwareMonitorLib.dll to collect sensor data. The Python add-on then reads the results through a local named pipe.

If you strongly prefer pure Python add-ons, do not want a companion executable process, or dislike bridge-based designs, this add-on is probably not for you.

What The Add-on Does

• Reads CPU temperature, GPU temperature, GPU usage, VRAM usage, and fan speeds.
• Uses a local bridge process instead of the old Libre Hardware Monitor web server.
• Keeps the legacy web server disabled to avoid LAN exposure.
• Prompts before starting PawnIO installation when PawnIO is missing.
• On the first startup after installation, asks whether PawnIO should also be removed when this add-on is uninstalled, and stores that choice in a marker file.
• During add-on removal, installTasks.py reads the saved choice and decides whether PawnIO should be uninstalled automatically.

PawnIO Removal Preference

On the first run after installation, the add-on shows a dialog that explains what PawnIO does and asks whether it should also be removed when this add-on is uninstalled later.

• Choosing Yes means the add-on will try to uninstall PawnIO automatically when the add-on is removed.
• Choosing No means PawnIO will be left installed.

Removing PawnIO may affect other software that also depends on it, and Windows may ask for administrator permission during removal.

For a clean removal, after uninstalling this add-on you must wait five minutes and then restart Windows so any remaining temporary cleanup files can be deleted completely.

Security Model

• No TCP listener is required for normal operation.
• No data.json web endpoint is exposed to the LAN.
• Sensor data is requested through a local named pipe only.

Limitations

• Sensor availability depends on hardware, firmware, drivers, virtualization, and Libre Hardware Monitor itself.
• Some virtual machines do not expose CPU temperature.
• Some GPUs do not expose VRAM usage or fan RPM sensors.
• The bridge executable is required in the current design and is not optional.
• Automatic PawnIO removal depends on Windows permissions and the locally installed PawnIO uninstaller.

First Use

On the first startup after installation, the add-on asks whether PawnIO should also be removed when this add-on is uninstalled later.

When you press a hardware shortcut for the first time, the add-on may also need to check whether PawnIO is installed, start the local bridge process, and warm up Libre Hardware Monitor sensor access.

If PawnIO is missing, the add-on will show a confirmation dialog before starting installation.

Author

• Author: haitun(haitun940624zx@gmail.com)
• Website: https://www.zxrjy.net/