No permissions!!! This is a sweet app  I don't need it but found it useful when setting up digital scale level or hanging the occasional picture. Just keep in mind when calibrating that most smartphones aren't made with flat edges and make proper adjustments. In example; case-back of Galaxy S has a ~wave~  device therefore cannot sit flush. Sides have buttons for power and volume but mic edge is straight. With that in mind use leading edges w/o buttons and you'll get more accurate readings. Looks cool too.