Hello guys...
The following was implemented as a hobby project by my sister n her friend.So i assure you IT REALLY WORKS ....
So read on...
MOBILE BUG is a basically a RF detector,which detects GHz frequencies used by mobile phones. So it can be used to prevent use of mobile phones in examination halls, confidential rooms, etc.It detects all incoming,outgoing,SMS,video transmission ONLY IF MOBILE IS ON!!!. Frequency range used by mobile phones are 0.9 to 3 GHz,so our circuit detects the waves in this range.
COMPONENTS YOU REQUIRE:
- 5 inch long antenna
- IC1:Opamp IC CA3130
- IC2:NE555 timer IC
- T1:Transistor BC548
- CAPACITORS:
- C3:Disk capacitor 0.22µF
- C1,C2: 22 pF capacitor
- C4:100µF 16V
- C5:47PF
- C6,C7:0.1µF
- C8:0.01µF
- C9:4.7µF 16V
- RESISTORS:
- R1,R3:2.2 mega ohm
- R2:100K ohm
- R4:1 K ohm
- R5: 12 K ohm
- R6: 15 K ohm
- LED1
- 12 V DC supply
- PZ1: Piezzo Buzzer
- Switch
Here is the circuit diagram:
(click on it to enlarge)
HOW IT WORKS:
Firstly, antenna captures the RF signals from mobile.Then 0.22
disk capacitor (C3) to capture the RF signals from the mobile phone. The lead length of the capacitor is fixed as 18 mm with a spacing of 8 mm between the leads to get the desired frequency. The disk capacitor along with the leads acts as a small gigahertz loop antenna to collect the RF signals from the mobile phone.
disk capacitor (C3) to capture the RF signals from the mobile phone. The lead length of the capacitor is fixed as 18 mm with a spacing of 8 mm between the leads to get the desired frequency. The disk capacitor along with the leads acts as a small gigahertz loop antenna to collect the RF signals from the mobile phone.
IC1 is used (in negative feedback condition)as current to voltage converter,with capacitor(c3) connected between this inverting and non-inverting terminals.And there is a output CMOS Transistor which swings output between 10mV.Then C3 intercepts the mobile signal and creates,stores energy ,and transfers the same to IC1 in form of small currents,thus upsetting its balance.IC1 converts these changes into voltages.
On the other hand C4 along with R1 keeps non-inverting terminal stable.And if C4 has to discharge it does through R2.
If there is a detection of a mobile signal then the output of IC1 becomes high and low alternately according to the frequency of the signal as indicated by LED1. This triggers monostable timer IC2 through capacitor C7. Capacitor C6 maintains the base bias of transistor T1 for fast switching action. Low value of R6 and C9 helps to keep time delay thus avoiding any unwanted change in output audio through buzzer.
Then assemble all the stuffs as shown in circuit designs on a small PCB. Make it as compact as possible to make it portable.
when you are done with all these , YOU WILL BE ABLE TO SEE THE LED FLASH WHEN THERE IS SOME KINDA TRANSMISSION !!!!!!!!(within 1.5 metres )
If you want data sheets of any components just visit alldatasheets.com
The total cost of the whole stuff is about RS.200.
So all i want to say is "ITS REALLY COOL TRY OUT!"
LAST SAY- I wanna thank my sis for sharing her project with me.And any problems mail me .And lastly any mistakes regretted. PLZ comment to encourage me
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