Long Range Cell Phone Detector Using LM358

In this project, we are demonstrating the Long Range Cell Phone Detector using LM358. This is a project of an exceptionally sensitive long-range cell phone detector circuit utilizing an LM358 IC. The circuit can identify a mobile phone from 10 to 12 meters away however it relies upon the output signal quality of the cell phone. In the testing, the circuit gave me different ranges of detecting cell phone with different mobile phones, it has detected some cell phones from 4 to 5 meters span and some from 10 to 12meter range.

The circuit is additionally a good battery saver, it will draw just 400µA in standby condition because of which a 9V battery will last more.

Hardware Components

S.no	Components	Value	Qty
1	Op-Amp IC	LM358A	1
2	Op-Amp IC	LM358B	1
3	Transistor	2N3904	1
4	Diode	1N34	2
5	Piezo Buzzer	–	1
6	Antenna	3 inch	1
7	LED	–	1
8	Resistor	1K, 100KR, 470Ω	1, 1, 1
9	Capacitor	560pF	1
10	Battery	9V	1

Circuit Diagram

Circuit Operation

In this section we explained the circuit operation of the Long Range Cell Phone Detector using LM358. The core of the circuit is an LM358 IC, LM358 is an operational amplifier IC. It contains 2 separate operational amplifiers in a single bundle. In this circuit we have utilized both the inward intensifiers for better sensitivity. An NPN transistor is associated with the output of the circuit to drive the piezo ringer and the LED. The circuit is utilizing two 1N34 germanium diodes at the input, any comparative germanium diodes will work here. The sensitivity of the circuit can be balanced with a 100K variable resistor.

Applications and Uses

The applications and uses of cell phone detector are following

• This circuit is used for detecting cell phones used for spying and unauthorized transmission of sound and video.
• This circuit can also be used at the examination halls, meetings to detect the presence of mobile phones, and prevent the use of mobile phones.