本研究應用自製手機來電閃（含發光二極體及檢波二極體）來呈現閉管駐波實驗結果。實驗包含手機訊號屏蔽器、鐵絲網製閉管及自製手機來電閃，開啟手機訊號屏蔽器，並於閉管中移動自製手機來電閃，可觀察到自製手機來電閃之發光二極體在特定位置有亮暗之現象。利用閉管駐波原理及經過測量駐波波腹位置可計算手機訊號屏蔽器所發出之電磁波頻率。

In this paper, home-made Cellphone Signal Detector (includes Light emitted diode and Schottky diode) are used to demonstrate and conduct standing wave experiment in tubes open at one end and close at the other end. The whole experiment setup includes Cellphone Signal Shielding box, home-made Kundt's tube and Cellphone Signal Detector. Using the Cellphone Signal Shielding box as a signal source and adjusting the Cellphone Signal Detector locations in the Kundt's tube, bright LED will be spotted. Using the standing wave theory and the locations of the bright LED, the frequency of the Cellphone Signal Shielding box can be calculated.