Pendulum straightedge

Another way to measure the length of a thread or arbitrary length is with the help of a pendulum from a telephone.

The thread must be fastened tightly. For example on a nail. If you hold the end of the thread in your hand the measurements may be incorrect.

With free swings, the application will show the length of the thread from the fixed end or the thread to the center of mass or your phone / tablet. Usually to the middle of the screen or the phone / tablet.