Having a dual-monitor setup can significantly boost your productivity, whether you’re a coder, designer, writer, or just someone who juggles multiple applications at once. While dedicated monitors can be expensive, you might have a perfectly good laptop gathering dust. Can you repurpose that old laptop as a secondary display using an HDMI cable? The short answer is: not directly, but there are clever workarounds we can explore. Let’s dive in!
Understanding HDMI and Laptop Displays
Before we get into solutions, it’s crucial to understand how HDMI works, especially on laptops. HDMI, or High-Definition Multimedia Interface, is a widely used connector for transmitting both audio and video signals.
Most laptops are equipped with HDMI output ports. This means they’re designed to send video signals to an external display, like a TV or monitor. Think of it as a one-way street for video. The laptop is the source, and the external display is the receiver.
Laptops generally lack HDMI input ports. An HDMI input port would allow the laptop to receive a video signal from another device, essentially turning it into a monitor. The absence of this input capability is the primary obstacle to using a laptop directly as a second screen with just an HDMI cable.
The Limitation of Direct HDMI Connection
Trying to connect two laptops with an HDMI cable to use one as a second monitor won’t work in most cases. When you plug an HDMI cable into the ports of both laptops, they will both try to output a display signal, creating a conflicting scenario. Neither laptop is designed to receive the signal from the other through HDMI. You’ll likely end up with both screens displaying their normal output, or potentially no display at all.
Software Solutions: Bridging the Gap
Since we can’t rely on a direct HDMI connection, we need to explore software solutions that can effectively turn your old laptop into a second monitor. These solutions generally work by using your network connection (Wi-Fi or Ethernet) to transmit the display signal.
Utilizing Windows Built-in Wireless Display Feature
Modern versions of Windows offer a built-in feature that allows you to use another computer as a wireless display. This feature leverages the Miracast technology.
Checking for Miracast Compatibility
Before proceeding, you need to ensure that both your primary and secondary laptops support Miracast. To check, open the Command Prompt on both laptops and type dxdiag. Press Enter. After the DirectX Diagnostic Tool loads, click “Save All Information” and save the text file. Open the saved file and look for “Miracast” in the report. If it says “Available,” your device supports Miracast.
If your old laptop doesn’t support Miracast, you can explore purchasing a USB Miracast adapter.
Setting up the Wireless Display Connection
On your old laptop (the secondary display), go to Settings > System > Projecting to this PC.
Configure the settings to your preference. The most important setting is “Available everywhere on secure networks” or “Available everywhere.” Also, set “Ask to project to this PC” to “First time only” to avoid constant permission requests.
On your main laptop, press the Windows key + K to open the “Connect” pane.
Select your old laptop from the list of available devices.
You might be prompted to enter a PIN on the secondary laptop. Follow the on-screen instructions to complete the connection.
Troubleshooting Wireless Display Connection
- Ensure both laptops are on the same network.
- Check firewall settings. Make sure Windows Firewall or any third-party firewall isn’t blocking the connection.
- Update graphics drivers. Outdated drivers can cause compatibility issues.
- Restart both laptops. A simple restart can often resolve connectivity problems.
Using Third-Party Applications
Several third-party applications are specifically designed to turn a laptop into a second monitor over a network connection. These applications often offer more features and better performance than the built-in Windows option. Some popular options include:
- Spacedesk: Spacedesk is a free application that turns your Android or Windows device into a second monitor. It works by installing server software on your main computer and client software on the device you want to use as a second monitor.
- Deskreen: Deskreen is another free and open-source application that shares any screen to any device with a web browser. This is also a useful alternative to HDMI splitter, matrix or wireless HDMI dongle.
- TwomonUSB: TwomonUSB works via USB connection and provides a stable and fast connection for using your laptop as a second monitor.
- iDisplay: iDisplay offers both wireless and USB connection options, providing flexibility depending on your network conditions.
Installing and Configuring Spacedesk (Example)
Let’s take a closer look at how to set up Spacedesk, as it is a popular and free option.
Download and Install Spacedesk Server on your main computer: Go to the Spacedesk website and download the server software for your operating system. Install the software, ensuring you have administrator privileges.
Download and Install Spacedesk Viewer on your old laptop: Download the Spacedesk viewer app for Windows on your secondary laptop from the Spacedesk website. Install the viewer.
Connect to the Server: Once both the server and viewer are installed, launch the Spacedesk viewer on your old laptop. It should automatically detect the Spacedesk server running on your main computer. If it doesn’t, ensure both devices are on the same network.
Adjust Display Settings: After the connection is established, you can adjust the display settings on your main computer to configure the second monitor. Go to Settings > System > Display and you should see the second monitor listed. You can then configure its resolution, orientation, and position relative to your main display.
Pros and Cons of Third-Party Applications
- Pros: Generally offer better performance and more features than the built-in Windows option. Support for both Wi-Fi and USB connections. Cross-platform compatibility (some apps).
- Cons: May require payment for premium features. Performance can be affected by network conditions. Potential security concerns with third-party software (always download from reputable sources).
Optimizing Performance
Regardless of the method you choose, performance can be a concern, especially with wireless connections. Here are some tips to optimize performance:
- Use a 5 GHz Wi-Fi network: 5 GHz Wi-Fi generally offers faster speeds and less interference than 2.4 GHz.
- Minimize network traffic: Close unnecessary applications that are using bandwidth on both laptops.
- Lower the resolution: Reducing the resolution of the second display can significantly improve performance.
- Use a USB connection (if available): A USB connection will generally provide a more stable and faster connection than Wi-Fi.
- Close unnecessary background applications: Free up system resources on both laptops.
Security Considerations
When using software solutions to turn your laptop into a second monitor, it’s important to be aware of potential security risks:
- Download software from reputable sources only. Avoid downloading software from unofficial websites, as they may contain malware.
- Keep your software up to date. Software updates often include security patches that address vulnerabilities.
- Use a strong password for your Wi-Fi network. This will help prevent unauthorized access to your network and devices.
- Be cautious about granting permissions to applications. Only grant permissions that are necessary for the application to function.
Alternatives to Using a Laptop as a Second Monitor
While repurposing an old laptop as a second monitor can be a cost-effective solution, it’s not always the ideal option. Here are some alternatives to consider:
- Purchasing a dedicated monitor: A dedicated monitor will generally offer better image quality, brightness, and refresh rate than a laptop screen. They are designed specifically for display purposes, offering a superior visual experience.
- Using a portable monitor: Portable monitors are lightweight and compact, making them ideal for travel or situations where you need a second screen on the go.
- Using a tablet as a second monitor: Some tablets, such as iPads, can be used as second monitors with the help of apps like Duet Display.
- Ultrawide monitors: An ultrawide monitor can offer a similar level of screen real estate as a dual-monitor setup, but with a cleaner and more streamlined appearance.
Conclusion
While you can’t directly use an HDMI cable to turn a laptop into a second monitor, software solutions offer viable alternatives. By using the built-in Windows wireless display feature or a third-party application like Spacedesk, you can effectively repurpose your old laptop and create a dual-monitor setup. Remember to optimize performance and prioritize security when implementing these solutions. If you’re looking for a more permanent and high-quality solution, consider investing in a dedicated monitor. Ultimately, the best option depends on your individual needs, budget, and technical expertise. By following these guidelines, you can make an informed decision and create a more productive and efficient computing experience.
Can I really use my old laptop as a second monitor with HDMI?
No, generally, you cannot directly use the HDMI port on an old laptop as an HDMI input. Most laptop HDMI ports are designed for outputting video to an external display, not receiving video input. They function primarily as a way to connect your laptop to a TV or monitor.
However, there are alternative methods to achieve a similar result. You can use software solutions like spacedesk or virtual network computing (VNC) to effectively turn your old laptop into a second display for your main computer, sharing the display via your local network. These methods don’t rely on the HDMI port acting as an input.
What software options are available to make my old laptop a second monitor?
Several software options allow you to extend your desktop onto another device, including spacedesk, VNC (Virtual Network Computing) clients like TightVNC or RealVNC, and even the native Windows feature “Projecting to this PC”. Spacedesk is a popular free option specifically designed for turning Android tablets and phones, or other Windows computers, into secondary displays.
VNC is a more general-purpose remote access tool, but it can also be configured to function as a second monitor. “Projecting to this PC” is integrated directly into Windows and provides a seamless experience, however it might not be available in older operating system versions. The best option will depend on your specific requirements and operating system.
What are the system requirements for using these software solutions?
System requirements vary depending on the specific software you choose. Generally, both your main computer and the old laptop will need to be running a compatible operating system. spacedesk, for example, supports Windows 7, 8.1, and 10, and requires that the spacedesk Driver software is installed on the primary PC, and the spacedesk Viewer application on the secondary device.
For VNC, the requirements can be slightly broader, and you’ll need to install a VNC server on the main computer and a VNC client on the old laptop. Also, both devices need to be connected to the same local network, typically via Wi-Fi or Ethernet.
How does spacedesk work, and is it free?
spacedesk works by installing a driver on your main computer (the one you want to extend the display from) and a viewer application on your old laptop. The driver captures the screen output from your main computer and sends it over your local network to the viewer application running on the laptop.
Yes, spacedesk is free for personal use. It doesn’t require any payment for its core functionality. However, always verify the license agreement for the most up-to-date details regarding usage terms.
What are the advantages of using software-based solutions over hardware solutions?
Software-based solutions are often more cost-effective and require less physical setup than hardware solutions. You don’t need to purchase any additional cables or adapters, and the process of installing and configuring the software is usually straightforward and relatively quick.
Furthermore, software solutions offer greater flexibility. You can easily switch between using the old laptop as a second monitor and using it for other tasks, simply by closing the viewer application. They also may support wireless connectivity, reducing cable clutter.
What are the limitations of using an old laptop as a second monitor this way?
One major limitation is the reliance on your local network. The performance of the extended display will be directly affected by the speed and stability of your network connection. A slow or unreliable network can result in lag, choppiness, or disconnects.
Another limitation is increased CPU and network usage on both computers. Sending and receiving video data over the network requires processing power. This can potentially impact the performance of other applications running on both devices, especially if they are older and less powerful.
What alternatives are there if I really need a hardware solution using HDMI?
If you absolutely need a hardware-based solution and your old laptop’s HDMI port is only for output, consider using a USB to HDMI capture card. These devices allow you to connect an HDMI source to your computer via USB. Then using appropriate software on the computer, you can display the source on the screen.
However, this setup is more complex and potentially expensive. Also, it usually introduces some latency. These capture cards are commonly used for video recording and streaming rather than for extending a desktop, so the user experience may not be optimal compared to using a dedicated monitor.