Touch stylus capable of detecting pressure on a tip and related optical-mechanical system

A touch stylus capable of detecting pressure on its tip is disclosed in the present disclosure. The touch stylus includes a body, a tip, and a pressure sensing module disposed between the body and the tip for detecting a pressure on the tip. The pressure sensing module includes a lighting unit, a pressure sensing unit connected to the tip, and a controller electrically connected to the lighting unit and the pressure sensing unit. The pressure sensing unit detects a movement of the tip relative to the body, and generates a corresponding electrical signal. The controller receives the electrical signal to drive the lighting unit for generating a corresponding optical signal. A scintillating frequency of the optical signal and a value of the electrical signal are in direct proportion, and an optical detector can transform the optical signal into the pressure on the tip.