In today's workflow, the need for more screen space is often a challenge, but purchasing a new physical display isn't always possible or practical. Fortunately, old or idle laptops can be repurposed as full-fledged secondary monitors for your main computer. This setup allows you to conveniently display reference information, instant messaging apps, or graphics without cluttering your main workspace.
Using a wireless connection WiFi Using a video signal to transmit a video signal eliminates the need to run unnecessary cables across the room, preserving the aesthetics of the workspace. While a wired connection typically provides lower latency, modern wireless standards can achieve acceptable image quality for office tasks. The main thing is to configure the software correctly and ensure the stability of your local network.
Before setting up, it's important to understand that image quality directly depends on the router's power and the radio channel's congestion. Ideally, both devices should be connected to the same network, preferably via the 5 GHz frequency band, to minimize lag. Below, we'll discuss the most effective methods for achieving this, from built-in operating system tools to specialized software.
Technical requirements and network preparation
To successfully implement a project to turn a laptop into a second screen, a number of basic technical requirements must be met. First and foremost, both devices—the primary PC and the receiving laptop—must be in the same location. local networkThis means that they must be connected to the same router, either via cable or over the air.
Bandwidth is a critical parameter. High-definition video streaming requires a stable connection. If your router supports dual-band operation, it is highly recommended to use the band. 5 GHz, as it is less congested and provides higher data transfer speeds compared to the classic 2.4 GHz.
⚠️ Note: When using a guest WiFi network or corporate networks with AP Isolation, devices may not be able to see each other. In such cases, you should switch to your main home network or adjust your router's security settings.
It's also worth making sure both devices have up-to-date network adapter drivers. Outdated software can cause connection interruptions or significantly reduced data packet transfer speeds. Check the Device Manager and update your network adapter software if necessary.
Built-in Projection feature in Windows 10 and 11
Windows operating systems, starting with version 10, have a built-in ability to use a computer as a wireless display. This feature is based on technology Miracast and doesn't require third-party software, making it the simplest solution for one-time tasks. However, please note that this option is not available in all OS editions and may not be available on some laptop models.
To activate signal reception mode on a laptop that will act as a monitor, you need to go to the system settings. Open the menu Parameters, then select the section System and find the item Projecting to this computerIf the feature is not active, the system will prompt you to install the additional component through the Windows component management menu.
Once enabled, you can choose visibility options: whether the computer is accessible to all devices on the network or only to those authorized by the code. On the primary computer, press the key combination Win + K, after which a list of available displays will appear in the sidebar. Select your laptop from the list, and the image will be broadcast.
Why might the function not work?
The built-in projection function depends on your network adapter's support for Wi-Fi Direct technology. Some older or low-end Wi-Fi cards don't have hardware support for Miracast, even if the drivers are installed correctly. In such cases, the system will return an error when attempting to enable signal reception.
It's important to note that the built-in method can exhibit noticeable mouse cursor lag, making it unsuitable for dynamic tasks like gaming or video editing. However, for static content, such as reading documentation or viewing graphs, the quality is quite acceptable. If the system reports that the device doesn't support reception, you'll have to resort to third-party solutions.
Using Spacedesk to extend your desktop
One of the most popular and flexible solutions for creating a virtual monitor is the program SpacedeskIt operates on the client-server principle: the driver is installed on the main computer (the server), and the client application is installed on the laptop, tablet, or smartphone that will be used as a display. The main advantage of this method is its cross-platform nature and the ability to work over a local network without being tied to a specific hardware manufacturer.
The setup process begins with downloading and installing Spacedesk DRIVER On the primary PC. After installation, you must restart the computer to ensure the network driver is properly initialized. On the second device (laptop), download and launch Spacedesk Viewer. When launched, the client will automatically scan the network and find the server.
☑️ Checking Spacedesk settings
The name of your primary computer will appear in the list of available connections. Click it, and after a few seconds, your desktop will expand. In the driver settings on the primary PC, you can fine-tune the image quality, color depth, and refresh rate. This allows you to find the right balance between smooth image quality and network load.
| Parameter | Description | Impact on performance |
|---|---|---|
| Color Depth | Color depth (16-bit / 32-bit) | 32-bit requires more bandwidth, but the colors are more accurate. |
| Frame Rate | Frame refresh rate | High FPS increases CPU and network load |
| Quality | Image compression ratio | Maximum quality may cause lag on weak WiFi |
| Bandwidth Limit | Bandwidth limitation | Helps reserve the channel for other tasks |
It's worth mentioning that Spacedesk creates a virtual video device in the system, allowing Windows to recognize the connected laptop as a fully functional second monitor. You can change its resolution, orientation, and position relative to the main screen in the standard menu. Screen parametersThis gives complete freedom in organizing the workspace.
Alternative solutions: Deskreen and Splashtop
If standard methods do not meet your requirements, it is worth paying attention to alternative programs such as Deskreen or SplashtopDeskreen is unique in that it works through a browser: no special software needs to be installed on the client device (laptop)—just open a web page and scan a QR code or enter a PIN. This makes it ideal for temporary use on other people's devices.
Deskreen operates using WebRTC technology, which delivers low-latency video directly to the browser. A server component is installed on the host computer, which captures the image from the video card and streams it to the local network. This method is especially convenient if the receiving laptop runs an operating system other than Windows, such as Linux or macOS.
In turn, Splashtop is known for its high quality image transmission and is often used for remote access, but the function Second Monitor Paid versions allow you to use it specifically for screen expansion. It provides excellent color reproduction and supports multitouch if your laptop has a touchscreen. However, a subscription may be required for full-time use.
Choosing between these programs depends on your priorities: if simplicity and no client installation are important, choose Deskreen. If you need maximum quality and are willing to pay for convenience, consider Splashtop. Free versions often have session time or image quality limitations, which are worth considering when planning.
Optimizing your WiFi network to minimize latency
Even with powerful equipment, wireless connections are susceptible to interference, which can manifest as artifacts on the screen or cursor twitching. To minimize the impact of external factors, it is recommended to manually select the least congested WiFi channel. This can be done through the router settings interface, usually accessible at 192.168.0.1 or 192.168.1.1.
In the wireless settings (Wireless Settings) find the parameter Channel and switch it from "Auto" to a specific value. For the 2.4 GHz band, channels 1, 6, and 11 are considered best, as they don't overlap. For 5 GHz, there's a wider choice of channels, so it's best to use a WiFi network analyzer on your smartphone to find a free frequency.
⚠️ Note: Router interfaces are constantly updated by manufacturers. The location of channel and frequency settings may differ from those described. If you are unsure, consult the documentation for your router model or your ISP to avoid disrupting your network.
It's also worth disabling power saving for the network adapter on both devices. In Windows Device Manager, find your WiFi adapter, go to Properties, and then on the Power tab Power management Uncheck "Allow the computer to turn off this device to save power." This will prevent brief connection interruptions when the adapter attempts to go to sleep.
Comparison of connection methods and final recommendations
To summarize, the choice of connection method depends on your specific needs and the equipment you have. Built-in Windows tools are easy to use, but limited in functionality. Third-party programs like Spacedesk offer flexibility but require software installation. Wireless will always be inferior to wired HDMI or DisplayPort in terms of response time, but it's easier to deploy.
For office work, stock trading, or coding, the 30-50 ms latency typical of WiFi is practically unnoticeable. However, for gamers or color designers, this option should only be a compromise in extreme cases. Always evaluate the feasibility of using a wireless second screen in your specific scenario.
Keep in mind that using a laptop as a monitor increases the load on its battery and cooling system. During extended use, it's recommended to keep the laptop plugged in and monitor its temperature, especially if you're using vibrant wallpapers or dynamic content on a secondary screen.
Is it possible to connect 3 or more monitors via WiFi?
Theoretically, it's possible, but network performance will drop sharply. Each additional wireless screen shares the channel's bandwidth. For multi-monitor setups, it's best to combine wired connections with one wireless one, or use docking stations.
Frequently Asked Questions (FAQ)
Will the second monitor work if there is no internet access?
Yes, it will. A local network (LAN/WiFi) is used to transmit images, so internet access is not required. The main thing is that the router is turned on and the devices can see each other within their network, even without access to the outside world.
Does this drain the battery of the receiving laptop a lot?
Yes, receiving a video stream and keeping the WiFi module constantly active significantly increases power consumption. It is recommended to use the laptop connected to a charger to avoid rapid battery drain.
Is it possible to transmit audio to a second monitor via WiFi?
Most specialized programs (Spacedesk, Deskreen) transmit only the video signal. The audio typically remains on the primary device. However, some solutions, such as AudioRelay or Windows Sound settings, allow you to broadcast the audio stream separately, creating a virtual audio cable.
Why is the image on the second screen blurry?
This may be due to Windows scaling settings or a low bitrate in the client software. Try changing the resolution in the display settings to the recommended resolution for your laptop's display and increasing the transmission quality in the driver settings.