I'm using an iphone5 and new iPad for these apps. Cliinometer is the name of the app. I've compared it to other levels and it has been more accurate than any sight level I've used.
It was dark so just the screen is visible not the phone or couch it was on.
. And there is a couple machinist apps. But the only thing I find useful is wire size and drill size decimals or tap drill sizes. I don't use any of the feed or speed guides as I just feed and cut by feel and sight.