Cell Phone Detector Circuit using Op-Amp

Mobile Phone Detector Circuit using Op-Amp

Mobile Phone Detector is a Circuit that detects the presence of Mobile Phone up to a certain range like 1.5 meter . It detects the phone when an incoming call or outgoing call is made or when an SMS is sent or received or any GPRS used.

When the circuit detects an RF signal from an activated mobile phone, it gives an indication by switching ON an LED. The LED will start blinking and continues to blink until the incoming/outgoing signal stops. Mobile Phone detector can also be called as a Frequency Detector. Frequency Detector is simply a Current to Voltage Converter Circuit which detects the frequencies in between the range of about 800 MHz to 3GHz.

Materials Required:

S.N. COMPONENTSDESCRIPTIONQUANTITY
1LM358Dual Op-Amp1
2Resistor1 KΩ1
3Resistor100 K Ω , 200KEach 1
4Potentiometer2.2 M Ω1
5Capacitor1 µF, 16V(Electrolytic Capacitor) 2
6Capacitor100 µF, 16V(Electrolytic Capacitor) 1
7BC548NPN Transistor1
8LED5mmAny Color 1
9Power Supply4.5V Battery/Adapter1

Mobile Phone Detector Circuit using Op-Amp:

This circuit consists of an op-amp with some active-passive components. A LED is used for an indication of the presence of a cellphone. Op-amp is configured as Frequency Detector and its output is connected to a LED using NPN Transistor. The circuit diagram is given below. The circuit can be either assembled in a breadboard or in a Vero Board.

When a mobile phone is active, it radiates RF signal in the form of electromagnetic radiation. When the mobile phone radiates energy in the form of RF signal, Capacitor C2 absorbs it and used as an input to LM358 IC. The output of LM358 is connected to LED via Transistor which gets turned ON. Then the flashing of LED is observed. The potentiometer RV1 is used to adjust the sensitivity or range of the circuit. This is how you can make a Simple Phone Detector Circuit.

Subramanian
Subramanian

Subramanian MK, currently serving as a workshop instructor at Sakthi Polytechnic College, Erode Tamil Nadu. With a career spanning 25 + years, Subramanian MK has dedicated himself to advancing knowledge in Electronics and Communication Engineering (ECE). His passion for exploring new technologies has led to the development of numerous projects, showcasing expertise in IoT and PCB design.

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