Picture of simple mobile detector circuit
simple mobile detector circuit using  CA3130 op-amp

description source:   http://www.electroschematics.com/1035/mobile-bug-detector-sniffer/

This handy mobile  phone detector  can sense the presence of an activated mobile cellphone from a distance of one and-a-half metre. So it can be used to prevent use of mobile phones in examination halls, confidential rooms, etc. It is also useful for detecting the use of mobile phone for spying and unauthorized video transmission.

The circuit can detect both the incoming and outgoing calls, SMS and video transmission even if the mobile phone is kept in the silent mode. The moment the mobile  phone detector detects RF transmission signal from an activated mobile phone, it starts sounding a beep alarm and the LED blinks. The alarm continues until the signal transmission ceases.

Step 1: Components

Picture of components
components list

1, CA3130  - op-amp 
2, PCB
3, Resistors all 1/4W ,
    1.2M Ohm - 1
     2.2M Ohm -1
     1K Ohm -1
     100K Ohm - 1
4, Capacitors
     22 pf ceramic -3
     0.22uf ceramic -1
     0.1 uf  polyester/ceramic -1
    100uF/25V  Electrolytic  -1
5, Red LED -1
6, BC548 -1
7, 5Cm copper wire -1

MariC57 days ago


LavanyaR210 days ago
yaswanth raj3 months ago

Insted of using 12v shall v use 9v

TanveerA14 months ago

can i please get the breadboard equivalent for the given connection

TanveerA14 months ago

can i please get the bread board equivalent for the given connecton

sarathikkl7 months ago

hello friend, how long (distance) the circuit will detected the signal between the circuit and mobile phone

ye project kam bhi krta h ky...

y2kare_00710 months ago
Does this detect signals from smartphone.. 4g LTE? Also when I connected a battery the led stays on constantly.. Any solution?
y2kare_00711 months ago

will this circuit be able to detect 4G signals ?


patelkeyur465310 months ago
It's not working man
after lots of troubleshooting
really disappointed me....

bhai ye project bna liya ky .................................ye kam krta h ya nhi

MuthuL10 months ago

It detects only the signals from basic models.why it is not detecting the signals from smartphones???

Emran_khan10 months ago

This circuit detects simple mobile phones but not the smartphone. Furthermore this circuit detects the transmission and reception frequency of mobile phones that ranges from 0.9 to 3 GHz. Then what is the Tx/Rx frequency of smartphones?

gabat11 months ago

I would like to ask where is that brown wire connected to.

gabat gabat11 months ago

where is that wire connected to

Jestin_Cubetech (author)  gabat10 months ago

it's not an antenna ,output from mobile detector circuit.

Jestin_Cubetech (author)  gabat10 months ago

NC pin (no connection)

It's antenna....
patelkeyur465310 months ago
How can i increase frequency range?
y2kare_00711 months ago

Also if i want to make this circuit compact, can i use SMD components ? will the frequency range and sensitivity be affected if i do so ?

connecting buzzer and R4 parallel?????? or replace R4 by buzzer..

plz reply fast

ShitVrxxx11 months ago

CA3130 is not available. Can I use CA3140? Or could you please suggest another replacement for that component? Another thing, is it really necessary to use ceramic capacitors than the other types? Please respond. ASAP.

max jacob1 year ago

show me the full diagram

Jestin_Cubetech (author) 1 year ago
circuit diagram

if we are connecting buzzer like above then is there any need of 1k R in circuit?

please reply

xusetori1 year ago

Where to connect the buzzer ?

can someone please upload a circuit diagram including buzzer

how much the components cost

kkhanna21 year ago
without giving any input to CA3130 ic its giving thé output....pls help....thanks in advance

What if there is no available CA3130 op-amp is there any replacement for that? I hope you can help me with this.

atharva121 year ago
what voltage ceramic capacitors should i use
Jestin_Cubetech (author)  atharva121 year ago
16v generic ceramic capacitor
Where did you insert the buzzer, it's not on schematic ?
Needs an introduction to explain what it is & what it does. Not everyone can figure this out ... many are nubies.
Thank you for your valuable suggestions.
Much better. I never thought of the security uses. GREAT IDEA !!! CHEERS!