In this tutorial, we are demonstrating a sensitive cell phone detector circuit. We can also say it mobile phone detector, sniffer, or call locator. The circuit can distinguish a mobile phone from more than 10 feet away. The circuit can be utilized for an assortment of purposes, for instance, it very well may be utilized to detect mobile phones in examination halls, meeting rooms, or finding a lost phone, and so forth.
At the point when we dial a number from our mobile phones or send SMS and press the send button then our phone begins producing an RF signal to connect it to the closest tower. The circuit that appeared here will recognize this RF signal in both incoming and outgoing call or SMS conditions and produces a beep sound.
Hardware Components
The following components are required to make a Phone Detector Circuit
| S.no | Components | Value | Qty |
|---|---|---|---|
| 1 | IC | TDA2822 | 1 |
| 2 | Transistor | 2N4401 | 2 |
| 3 | Antenna | 5 inch | 1 |
| 4 | Diode | 1N34 | 2 |
| 5 | Speaker | 4 – 8Ω | 1 |
| 6 | Resistor | 620K, 4.7Ω, 1.2K, 220K, 10K | 1, 1, 1, 1, 1 |
| 7 | Variable Resistor | 10K, 20K | 1, 1 |
| 8 | Capacitor | 100nF, 10µF, 0.01µF, 100µF | 4, 2, 1, 1 |
| 9 | Battery | 9 – 12V | 1 |
TDA2822M Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of TDA2822
Phone Detector Circuit
Working Explanation
In this section, we are discussing the operation of the cell phone detector circuit. The circuit is utilizing two 1N34 germanium diodes for detecting the signals, two NPN 2N4401 transistors for strengthening the signals, and a sound speaker IC TDA2822M to drive a loudspeaker. The increase of the circuit can be balanced with a 20K variable resistor. The 10K variable resistor is utilized to modify the volume of the circuit.
The circuit can be worked from 9 to 12 volt DC. You can also utilize a 9-volt battery or 3 lithium coin size batteries and fit the entire circuit in a box to make it easy and compact.
Applications and Uses
The Cell Phone Detector Circuit is used to detect the cell phone whether you are doing an assessment in an examination hall or you are conducting a meeting where cell phones are not allowed.
