Trench Right App
Excavation of trenches might seem simple but if you aren't using a trench box or shoring then your trench must be excavated in a way so that the angles of repose (the angle made between the sides of your trench and the level ground around it) are within the limits of the soil you are digging in.
Sound complicated? Don't worry, Trench Right makes these calculations super easy! Just enter in some information about your trench's dimensions as well as the soil type as well as your penetrometer's TSF reading and they'll do the rest. Developed by Ingenious Robot, Inc. and sponsored by the Michigan Infrastructure & Transportation Association (MITA).
Download the app from the Apple Store.