Many users are faced with a situation where an old laptop remains idle after purchasing a new device. A natural question arises: Is it possible to make a monitor from a laptop? and use it as an additional display for your PC? The answer is not as clear as it seems at first glance, and depends on which method you plan to use. Connecting an HDMI cable directly to a laptop port most often does not work, since this connector is in most cases an output, not an input.
However, there are effective software and hardware ways to solve this problem. You can use built-in Windows functions, third-party utilities for image streaming, or go the more complicated route - disassemble the device and use only the matrix. Each of these approaches has its own advantages, limitations, and hardware requirements that must be considered before getting started.
Why a simple HDMI cable won't work
The most common mistake when trying to turn a laptop into a monitor is trying to connect a video cable from a desktop computer directly to the video output of the device. In the vast majority of models ASUS, Lenovo, Acer and other manufacturers, the HDMI port only works for signal output. This means that it sends the picture to the TV or projector, but cannot receive it.
From a technical point of view, video input requires a specific video capture chip, which is not found in standard laptop motherboards. Even if you find a model with a combination connector, it will be the exception that proves the rule. Trying to send a signal to the output may damage the video card or the port itself, so you need to act with extreme caution.
To understand whether your device can receive a signal, you need to study the technical documentation. If the specifications do not explicitly mention a function HDMI Input or Video In, then this method is not suitable for you. In such cases, you have to look for workarounds using a network connection or hardware adapters.
Using built-in Windows tools for remote access
The most affordable and secure way to turn your laptop into a second screen is to use the built-in Project to This PC feature in Windows 10 and 11. This method works over a local Wi-Fi or Ethernet network, without requiring the purchase of additional devices. To activate the function you need to go to Settings → System → Project to This PC.
You need to enable the "Available everywhere" or "Available on secure networks" option, and also allow connections from devices with a PIN code. After setting up on your main computer, open the Connection menu and select your laptop from the list of available devices. The image will appear on the laptop screen with a slight delay, which depends on the quality of the wireless network.
This method is ideal for working with documents, browsing the web, or managing files, but it is not suitable for dynamic tasks. Input lag and video compression make comfortable gaming or professional video editing impossible. However, for expanding your workspace, this is a great and free solution.
⚠️ Attention: Make sure both devices are connected to the same Wi-Fi network. If one of the computers is on a guest network, discovery may not work due to client isolation settings.
- Wi-Fi (free)
- USB cable (low latency)
- Hardware replacement (difficult)
- Haven't tried it yet
Third party programs to reduce latency
If the built-in Windows tools are not stable enough, you can turn to specialized software. Utilities like Spacedesk, Deskreen or Mouse without Borders offer alternative image transmission algorithms. They often provide higher refresh rates and better traffic optimization than standard Microsoft drivers.
The program is especially worth noting Spacedesk, which turns any tablet or laptop into a second monitor with multi-touch support. It creates a virtual display that the system recognizes as a separate screen. To configure, just install the driver on the main PC and the client application on the laptop, after which they will automatically find each other on the local network.
For maximum connection quality, it is recommended to use a cable connection via Ethernet for both devices. Wi-Fi, even the 5 GHz standard, can experience stuttering when transmitting large amounts of video data. If you plan to use the laptop as a monitor for games, then a delay of 50-100 milliseconds will be noticeable and can ruin the experience.
⚠️ Warning: Some antivirus programs may block connections between devices, considering them to be suspicious network traffic. Temporarily disable your firewall or add applications to exceptions.
☑️ Checking readiness for software configuration
Hardware modification: using only the matrix
If you need a full-fledged monitor without delays, software methods will not work. The only way to get a real-time image is to extract liquid crystal panel (matrix) from the laptop case. This process requires disassembling the device, removing the keyboard, touchpad, and case. The resulting matrix will need to be connected to a special controller.
The controller board is a device that converts the HDMI or DisplayPort signal into a format that the matrix can understand. These boards are universal, but you need to know exactly the model of your matrix. There is usually a sticker on the back of the screen with the full name, e.g. LP156WF4-SPB1. Using this code you can find a suitable controller on trading platforms such as AliExpress or specialized forums.
Making your own monitor from a laptop matrix is a fascinating process that allows you to get a screen with an original diagonal and resolution. However, you will have to come up with a case, since it is dangerous to place a bare matrix on the table. You will also need a power supply for the controller and possibly additional cables for the backlight.
What to do if the sticker on the matrix has worn off?
If the markings are not readable, you can try to find the controller based on the screen parameters: diagonal, resolution, location of connectors (LVDS or eDP) and number of pins. Often on enthusiast forums they help identify the model by a photo of the connector.
Comparison of connection methods
The choice of method depends on your goals and available resources. Software methods are easy to implement but suffer from latency. Hardware modification gives ideal results, but requires time, soldering skills and additional costs for the controller. Let's compare the key parameters of the different approaches to help you make your decision.
| Method | Delay | Cost | Complexity | Picture quality |
|---|---|---|---|---|
| Windows Projection | High (50-150 ms) | 0 rub. | Low | Average (compression) |
| Third party software (Spacedesk) | Medium (30-80 ms) | 0-500 rub. | Low | good |
| Video capture (USB Capture) | Low (10-30 ms) | 1500-5000 rub. | Average | Excellent |
| Direct Matrix Connection | Minimum (0 ms) | 1000-3000 rub. | High | Ideal (native) |
If you're looking for a compromise that doesn't require disassembling the laptop but provides low latency, it's worth considering using an external video capture card (Video Capture Card). This is a small device that connects to a laptop's USB port and has an HDMI input. By connecting your main computer to this capturer, you will be able to see the image through the OBS program or the standard "Camera" in Windows.
The cost of such devices varies from budget Chinese models to professional solutions. For simple tasks, the cheapest option will be enough, which will provide a delay of about 20-30 milliseconds. This is enough for most games and work, but not for competitive shooters where every split second matters.
Before purchasing a matrix controller, be sure to check the backlight voltage. Some older matrices require 12V, but modern eDP screens can operate on 5V. Incorrect voltage will damage the board instantly.
The nuances of using an old laptop as a monitor
Even if you have successfully converted your laptop into a monitor, there are a number of nuances that need to be taken into account for the longevity of the system. The keyboard and touchpad are not usually used in monitor mode, but they continue to consume power. It is better to disable them in Device Manager or use the “Charge Only” mode if there is such an option in the BIOS.
Cooling is another critical point. Laptops are designed to work with hot air escaping from the case. If you cover the ventilation grilles with the body of a homemade monitor or place it in a closed niche, overheating will occur very quickly. Make sure that air flow is free, especially if you are using a powerful controller inside the case.
It is also important to configure the power mode so that the laptop does not go into sleep mode when the mouse of the main PC is inactive. Go to Power → Configure power plan → Change advanced power settings and disable sleep transition. Otherwise, you will have to constantly wake up the device, which will negate the ease of use.
⚠️ Attention: If you use the video capture method, make sure that auto compression is disabled in the capture driver settings. Compression can reduce the clarity of text, which is critical for working with documents.
Final recommendations and safety
Before attempting any manipulation, especially disassembling the device, make sure you understand the risks. You may lose your warranty, if it is still valid, or damage the fragile matrix cables. If you are not confident in your abilities, it is better to entrust the work to professionals or choose a software method that does not require physical intervention.
Remember that an old laptop can be useful for more than just a monitor. It can serve as a media center, home server, or development test station. But if the goal is a second screen, then the choice of method depends on whether you are willing to put up with the delay or want the perfect picture at any cost.
The final choice is yours: a software solution gives instant results at no cost, while a hardware solution requires an investment of time and money, but gives a professional result. Either way, you shouldn't throw away your old laptop because it still has plenty of life as a useful peripheral.
The easiest way to get a second monitor is to use the Windows feature, but for games and videos, an external video capture or direct connection of the matrix to the controller is better.
Frequently Asked Questions
Is it possible to connect a laptop to a TV as a monitor?
Yes, but only in the opposite direction. You can connect your laptop to your TV via HDMI to use the large TV screen as a laptop monitor. But you cannot directly use a laptop as a monitor for a TV via HDMI, since the laptop port is not an input.
How much does a controller for a laptop matrix cost?
The price of a controller board usually varies from 1000 to 3000 rubles, depending on the model and functionality. Cheap options may not have audio output or support for high refresh rates.
Does Spacedesk work on Android and iOS?
Yes, Spacedesk has client applications for mobile devices. You can use your tablet or old smartphone as a secondary screen by installing an app from Google Play or the App Store.
What should I do if the picture jerks when connecting via Wi-Fi?
The jerking is caused by an unstable connection or channel overload. Try switching both devices to the 5 GHz network, connecting them via an Ethernet cable, or reducing the resolution and refresh rate in the program settings.
Can a laptop be used as a monitor without a keyboard?
Yes, this is standard practice. After setting up the system, the keyboard and touchpad are not needed. However, if you decide to disassemble the laptop and leave only the matrix, you will have to take care of the case and power separately.