This Ex-Apple Engineer's New App Turns Your iPad Into A Second Display For Your Mac

Instead of letting your iPad collect dust when you're not using it, Duet Display turns your iPad into a second display for your Mac, using the iPad's charging chord to connect to your computer.

The app was created by Rahul Dewan, an engineer who worked at Apple for three years on the iPad and iMac.

"I think most people don't use two monitors, and this makes it simpler because you don't have to buy anything if have an iPad and Mac," Dewan told Business Insider. "Otherwise, you have this wasted display that is worth like $700, and it's just sitting there when you're using your Mac. Duet enables you to get some more productivity out of it."

In addition to giving you extra screen real estate (which is great for musicians, designers, and photo and video editors), Duet Display also takes advantage of the iPad's touch capabilities, allowing you to tap and scroll through whatever you choose to drag over to the second display.

While other apps like Air Display already exist that will turn your iPad into a second display, those apps connect your iPad to your Mac using wi-fi, which leads to a lot of lag. Duet Display, on the other hand, has zero lag, and it also offers a true Retina resolution that takes full advantage of the iPad's HD display.

Duet Display also offers energy saving options for people using older Macs that aren't as powerful. You can choose between regular and Retina resolution (you'll need a newer Mac for Retina mode to work seamlessly), but you can also switch between a 30 Hz and 60 Hz refresh rate.

Setting up Duet Display is a cinch. You just download the app on your iPad and for your Mac, restart your computer, and you're ready to go.

Because my work computer is a Mac Mini, I stuck to the regular resolution along with a 60 Hz refresh rate, and it worked well without any hiccups. While the Retina resolution certainly makes everything crisper, it also puts more work on your computer, but if you have a more recent Mac you should be all set.Business InsiderDuet Display is great for keeping an eye on Twitter or Slack.In use, Duet Display performed exactly how I'd like it to. I could drag a webpage with my Twitter feed or Slack over to my iPad's screen, and you can tap fullscreen to have whatever window you're displaying expand to fill the entire screen. YouTube videos played back smoothly, and I even played a game of Hearthstone just to see if it worked for games (it does, but most of the time it makes more sense to just game on your primary display).

Duet Display also works in either portrait or landscape mode.

Another bonus feature is that you can technically use Duet Display to turn your iPad into your only display, though that feature only works if you disable your Mac login, since Duet Display only works after you've logged in).

Duet Display launches tomorrow, and you'll be able to download the app right here.