The principle of touch control is that when a finger or other conductive material touches the panel, the panel will detect the change of surface capacitance and generate an electrical signal to judge the touch position. So you can control it with your fingers or other conductive materials; Materials that can't conduct electricity, such as traditional plastic resistive stylus, can't be manipulated. Previously, some netizens demonstrated that you can manipulate the iPhone with sausages or other foods. Some netizens also made their own iPhone stylus, and put a conductive cotton in front of the general pen tip to control the iPhone. At present, the capacitive stylus on the market mainly uses conductive cotton, rubber (coated with conductive paint) and conductive fiber, and its principle is to use conductive materials on the surface. Although the principle is simple, in fact, if the process requirements are not up to standard, it will easily break the pen and be insensitive. Many capacitance pen in the market are actually not up to standard, so it is better to use your fingers.