Cell Phone Detector Circuit Using LM358 This Cell Phone Detector which can sense about 4 to 5 meters of distance from activated mobile devices. So this cell phone detector circuits  can be used, where examination halls or mobile phone prohibited areas. Cell Phone Detector circuit easily detects or identify even when the mobile phone in silent mode, incoming and outgoing calls, SMS, using the Internet and Video transmission. Cell Phone Detector LED starts blinking and continues to blink up to the signal stops when it detects an RF signal from an activated Cell phone. Cell Phone Detector Circuit Working: Cell phone detector using LM358 circuit is shown above figure. which is constructed around LM358 IC and NPN transistor BC548. When a cell phone is active (ON) which radiates the RF signal that passes from space and that signal contains electromagnetic RF radiation from the cell phone. Capacitor C1 is used in the circuit to detect the RF signal from the mobile phone. When the ...