In this DIY, we are going to demonstrate a project on a long-range cell phone detector. This project is an exceptionally sensitive long-distance cellphone detector circuit that can detect cell phone signals from 30 to 40 feet away. It is an exceptionally helpful circuit and can be utilized to detect mobile phones at the spots where they are not allowed for example examination halls and so forth. The circuit can likewise be utilized to detect a spy cellphone or additionally for finding the lost mobile phone when the mobile phone is on vibrate mode.
The circuit cannot detect the speech or instant message content, it can just detect the encoded signal sound because of which we can comprehend that somebody has a mobile phone.
Hardware Components
The following components are required to make a Phone Detector Circuit
| S.no | Components | Value | Qty |
|---|---|---|---|
| 1 | IC | CA3140 | 1 |
| 2 | Transistor | 2N4401 | 1 |
| 3 | Piezo Buzzer | – | 1 |
| 4 | Diode | 1N34 | 2 |
| 5 | LED | – | 1 |
| 6 | Antenna | 3.5 inch | 1 |
| 7 | Resistor | 1M, 1.2K, 470Ω | 1 |
| 8 | Battery | 9 – 12V | 1 |
CA3140 Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of CA3140
Phone Detector Circuit
Working Explanation
The circuit is extremely straightforward and utilizing not many parts, which are two 1N34 diodes, CA3140 IC, transistor, LED, three resistors, and an optional buzzer, you can likewise evacuate the bell and utilize just LED with its 470 Ohms current limiting resistor.
Working of the circuit is fundamental, when we dial a number or send an SMS or MMS through our mobile phone then our mobile phone produces an RF signal to interface with its closest phone tower, the two diodes appeared in the circuit to detect these RF signals which are amplified by the CA3140 IC. The output is fed to the transistor, which becomes switches on and actuates the LED and the piezo buzzer. The working voltage of the circuit is 9 to 12V DC yet it can also be worked with 6 volt DC.
Applications and Uses
The long-range cell phone detector circuit is used to detect cell phones in the examination hall and also used to find the lost cell phone.
