Price: $0.99
Download link: iTunes
Clinometer is a very simple slope measurement app developed to turn your iPad into a useful tool for builders 0_о The fact of the matter is that by the means of this program you can measure and then precisely align your frames or use your iPad for more sophisticated jobs.
And all this is possible due to your iPad’s built-in accelerometer and compass. So, developers, learn how to use gadgets’ potential 
Well, for less than one dollar ($0.99) you equip your iPad with various sensors and other useful things. And this is much cheaper than a trip to building material store. The app is currently available for a limited time.