For Android, the premium version of Unified Remote comes close to what Actions offers, even if it isn't as snazzy. The $4 upgrade gives access to lots of app-specific control panels, plus a way to create your own panels.
Set up a small file server with battery backup
In terms of raw storage, an old phone or tablet can't compare to a networked hard drive. But it's good enough for documents or a small number of media files—especially if you can pop in a microSD card for extra capacity. Plus, mobile devices can hum along for days on battery power, so you can still get to your files even if someone shuts off your computer. Think of it as do-it-yourself cloud storage, without the cloud.
To transfer files onto your phone or tablet, you could just plug it into your PC and drag-and-drop. Or you could go the automated route: Install BitTorrent Sync on your PC and your phone, and use the "sync folders" option to back up whatever folders you want.
The easiest way to access Android files remotely is with AirDroid. Install the app on your phone and create a login (or just sign in with your Google account), then visit web.airdroid.com from any browser. After signing in, you'll be able to access your phone's file directory and snag anything you need. (Just make sure to disable "power saving mode" in AirDroid's settings first.)
Create a desktop calculator or document scanner
Tapping digits on a touch screen is easier than pointing and clicking on your PC's built-in calculator program. (PCalc for iOS and Real Calc for Android are both free for basic calculations, and you can upgrade to paid versions if you need more features.)
As long as you're making up for missing peripherals, you can also use your phone as a document scanner. CamScanner, available for both iOS and Android, is loaded with features, and you can try it for free. The paid version costs $5 per month on both platforms.
Dedicate it to calls and video chats
If you're working on a small laptop or an older PC with limited processing power, you may want to offload Skype calls, Google Hangouts, or other video chat applications to a separate phone or tablet. That way, you can free up your PC's resources—and its screen—for taking notes or pulling up reference files. This one's easy: All you need is a phone or tablet with a front-facing camera and a cheap stand or monitor mount. (You could also MacGyver your own phone stand or monitor mount for practically nothing.)
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