For those who are a freelancer or starting with an online job in this pandemic, having a multiple monitor is so important for having a productive work. For gamers, you can also use multiple monitor to check other task like web browsing or an in-game chat window while playing your favorite games.
There is an app called SpaceDesk, it is a simple app that lets you use your device like mobile phone, laptop or even desktop as an extended monitor for your main (primary) computer. Plus, this is the only app that allows you to connect up to 10 extended monitor. Other than that, it is FREE for everyone.
The only requirement for this app to work is both or all of the devices must be connected in one network (This is your router).
How to use SpaceDesk
First, you need to install the package for PRIMARY Machine. This machine is the main computer that you want to have a multiple display. You can download the installer at:
- Windows 10 (64bit): https://spacedesk.net/downloads/spacedesk_driver_Win_10_64_v0998_BETA.msi
- Windows 10 (32bit): https://spacedesk.net/downloads/spacedesk_driver_Win_10_32_v0998_BETA.msi
Next, on your phone, you need to install the SpaceDesk app for Android or iOS:
- Google Play: https://play.google.com/store/apps/details?id=ph.spacedesk.beta
- App Store: https://apps.apple.com/us/app/spacedesk-multi-monitor-app/id1069217220
Once you have downloaded and install the app for both devices. At the Primary Machine, search at the Cortana for Spacedesk Server. Open the app, and turn it ON (if its off).
In your mobile device, open the app spacedesk. Then connect to the desktop server.
Voila! You have now an extended monitor out of your mobile phone.
Depending on the speed of your network router, the smoothest experience is the default resolution which is the (1024 x 768), extending it to your phone’s resolution will give you a laggy experience. However, if you have router that has blitz speed you can have the maximum resolution without the lag.
But given this ability to use your phone as an extended monitor, this app is great enough for people who cannot afford yet to buy a monitor or in need of an external monitor for emergency task.
Addition
You could also try using your web browser as an extend monitor through their HTML5 viewer at http://viewer.spacedesk.net/, you only need the IP address of the server.
It is worth to note that refresh rates will drop extensively on both client and host devices if running resource-consuming games such as gta5. Thus being likely not the best option for gaming, the host device takes all the CPU, GPU resources to handle the transference of graphic data and client may stutter a lot if set in 60fps or standard color depth, high resolutions etc etc.