How to Use Your Spare Laptop as a Second Monitor
Transform your old device into an extra screen using wireless or wired methods.
1Expanding Your Digital Workspace
Adding a second monitor significantly enhances workflow by providing extra screen space for tabs and multitasking. While many users assume this requires purchasing new hardware, repurposing a spare laptop is a viable alternative. This process involves specific software configurations or hardware adapters to extend your desktop without buying a dedicated external display.
2Windows Wireless Casting Setup
Windows 10 and 11 users can utilize the built-in Miracast functionality to connect devices over Wi-Fi. By navigating to the Projecting to this PC settings and enabling the Wireless Display feature, you can link two machines. Pressing Windows key plus K on your main computer allows you to select the secondary laptop.
3Apple AirPlay Connectivity Requirements
Mac users can leverage AirPlay to turn a secondary MacBook into an extended display, provided the hardware is from 2018 or later. Both devices must be signed into the same Apple ID and connected to the same network. You manage these display settings through the System Settings menu under the Displays tab.
4Cross-Platform Software Solutions
For mixed operating systems like Windows and Linux, open-source tools such as Deskreen facilitate screen sharing over Wi-Fi. The software generates a QR code or URL that you open on the secondary device's browser. To extend the desktop rather than just mirroring it, you may require a virtual display dummy plug adapter.
5Overcoming Video Output Limitations
Most laptop HDMI ports are designed for video-out only, preventing direct cable connections for display extension. To bypass this, you can use an HDMI-to-USB video capture card. This hardware converts the signal, allowing your secondary laptop to receive the feed as if it were a standard webcam input for your primary device.
6Managing Latency and Performance
Wireless methods like Miracast and AirPlay are convenient but often suffer from slight lag, making them less suitable for high-speed gaming. Wired connections using capture cards generally offer lower latency than Wi-Fi alternatives. These wired setups are also effective for connecting consoles like a PlayStation or Nintendo Switch to your laptop.
7Software for Wired Feeds
When using a capture card, the secondary laptop treats the incoming video signal as a webcam feed. You can view this output using the built-in camera application or third-party software like OBS Studio. This approach works across Windows, Mac, and Linux, providing a more stable connection for tasks requiring smoother visual performance.
8Alternative Repurposing Strategies
If display extension does not meet your needs, an old laptop can serve other functional roles in a modern home. Many users choose to convert these devices into dedicated smart home hubs for centralized control. Evaluating your specific hardware compatibility is the essential first step before choosing between wireless or wired conversion methods.
Original article: Engadget — How to Use Your Spare Laptop as a Second Monitor