This Thing allows you to mount your phone in a 90 degree angle to your chest rig, so that you can use it for hand-free navigation and other applications.
Additional Parts needed:
3x30mm screws (or just print small rods, they don't need a thread. You are a maker, figure something out)
Rubber band to keep it closed securely
Flexible bands of 3mm thickness, to keep the phone in place - I picked this version instead of a clipping mechanism, to make the mount compatible with different size phones.