TC301A chip to do a body close to the induction program

Based TC301A chip body to make a proximity sensing, the principle of this scheme is to detect the presence or absence of a human body by detecting the amount of change in capacitance, this design principle is simple, easy to use, easy to operate, low cost.
Design scheme is as follows: can be done according to the principle of FIG pcb board as five feet outside the chip inductive coil, the inductive coil area made larger, farther proximity sensing distance or the smaller the capacitance value of a hexagonal close to the proximity sensor farther. This scenario may be the maximum sensing distance 7--9cm between the experimental data, 30mm * 30mm sensing area can sense the distance of 30cm (hexagonal capacitance value 20pF ). <ignore_js_op>