If you own an Android tablet, you probably get most of your real work done on a desktop or laptop PC, and use your tablet primarily for casual Web browsing and content consumption. But you can use your tablet to improve your productivity, too. Since a tablet is essentially a portable touchscreen, why not repurpose it during work hours as a secondary display?
In this article I'll outline how to configure an Android tablet (or a compatible Android smartphone) as a secondary PC display. I'll explain how to install a couple of apps on an Android-based tablet and on a Windows 7 PC, and then I'll show how to configure them to work together to extend (or mirror) the PC's desktop. These capabilities are not confined to Android and Windows 7, however; do some digging on your own, and you should discover other screen-mirroring apps for any version of Windows from XP forward, as well as for Mac OS X, iOS, and Android.
For the purposes of this guide, I'm going to focus on how to set up the least-expensive screen-extension application we could find; it's called Redfly ScreenSlider, and at of the time of this writing it was available for $1. (We tried to find a suitable free alternative, but had no luck. If you can find a better free alternative, share it with other readers in the Comments section below.) Alternatives such as Air Display or iDisplay are available for about $3 to $5, so even if you require a different app for your particular setup, it shouldn't break the bank.
What You Need
To use your Android tablet as a secondary PC display, you need a few things aside from the tablet and PC apps. First, you need a compatible tablet running Android 3.01 or newer (or a smartphone running Android 2.2 or newer) and Windows XP (32-bit) or Windows 7 (32 or 64-bit). For demonstration purposes we're using an app that works over a Wi-Fi connection, so the tablet and PC must be connected to the same network and reside on the same subnet.
Once you have downloaded the necessary apps, and you're sure that the tablet and PC are connected to the same network, the installation and configuration processes are pretty straightforward. Keep in mind that although I'm focusing on Android, Windows, and ScreenSlider here, the processes are very similar with the other apps I mentioned earlier. Typically you have to download the app to your tablet, download a companion “connector” app to your computer, pair the two devices, and then tweak a couple of settings to your liking.
Install the Tablet App, and Give Your Tablet a Name
The first step is to install the Redfly ScreenSlider app, which you can download from the Google Play store.
After installing ScreenSlider, run the app. The first time ScreenSlider launches, it will ask you to enter a unique name for your tablet. The name can be anything you like—it serves only to identify the tablet during the initial setup phase for the companion PC application. We used a Samsung Galaxy Tab for this project, so we named our tablet accordingly. After you enter a name, leave ScreenSlider running.
Install the Companion App on Your PC
With the tablet setup mostly complete, it's time to move on to your PC. The PC connector app is available for download on the ScreenSlider website. Install the ScreenSlider companion application using the default setup options. When the procedure is done, a ScreenSlider icon will appear in the system tray.
On our particular setup (Windows 7 Ultimate 64-bit), the ScreenSlider icon appeared in the system tray, but it didn't do anything when we left- or right-clicked it. We haven't seen other users complain about this issue, so that may have been an isolated incident. In any case, running ScreenSlider from its Start menu shortcut opens its menu just fine.
Connect to Your Tablet
After opening the ScreenSlider PC menu, click the Find Devices link at the top. A dialog box will open, and the app will scan your network for the tablet. If the tablet and PC are on the same network and subnet, and if the ScreenSlider app is running on the tablet, after a few moments the tablet should appear in the list of available devices, with its IP address and the name you entered in step two.
Double-click your tablet's entry in the list of devices; a window should pop up on the tablet's screen with a unique PIN. You need to enter that PIN into the connection window on the PC. Once you have done that, click OK, and the tablet should begin acting as a secondary display in extended desktop mode.
Tweak the Settings
ScreenSlider's default configuration puts the tablet in extended desktop mode and assumes that the tablet will be located to the right of the primary display. To change those settings, launch the ScreenSlider menu on the PC and choose Settings from the menu. In the resulting window, you can change a few basic options, such as the tablet's position or whether you want the program to launch with Windows and to check for updates. You also can set the tablet to mirror the PC's desktop; however, for the mirror function to work properly, you cannot set the PC's resolution higher than the resolution of the tablet's screen.
A Few Drawbacks
Using a tablet as a secondary display is definitely convenient, and it could be a real productivity booster, but it's not all good news. Although the quirks and incompatibilities of such a setup are different from app to app, ScreenSlider has a few worth mentioning. Windows 7 Aero effects are disabled when ScreenSlider is active and a tablet is connected. In addition, audio from your PC will not play on the tablet should you drag over a window that's playing audio, though the sound will continue to play normally through your PC's speakers.
In addition, the performance of such applications is highly dependent on the speed of your wireless network. On a slower or congested wireless network connection, you'll notice lag when dragging windows to and from the tablet's screen, and video playback will most likely drop frames. A few applications may not render properly either, but we had an issue only with Internet Explorer 9. Other browsers worked fine.
Regardless, being able to have items such as widgets, IM windows, or your inbox always open on a secondary screen can be useful. At the very least, you'll have put the otherwise-idle pixels on your tablet's screen to good use.