Here is a simple engineering project circuit of handy mobile cell phone detector (sniffer). This pocket-sizedmobile communication detector or sniffer can sense the existence of a mobile device. So it can be used to avoid the use of mobile phones in private rooms, examination halls, etc. It is also useful for detecting the use of mobile phone for s
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pying and other related activities. The circuit can detect incoming and outgoing calls, SMS, MMS, GPRS usage and video transmission even when the mobile phone is set aside in silent mode. The instant bug detects RF (Radio Frequency) transmission signal from a mobile phone, it produces a beep sound alarm. The circuit is able to detect all forms of mobile phone activity even when it is in silent mode. The circuit is designed as a sensitive RF detector. The RF signal diode 1N3491 forms the major element. Output signal from the diode is pre amplified by the transistor BFR96. It is a high frequency (Microwave frequency) low power transistor with huge current gain (approximately 15dB at 0. 5GHz) and bandwidth. The pre amplified signal is fed to next amplifier stage built around IC TL071, it is a low noise JFET input op amp with low input bias and offset current. The biFET technology gives high slew rate to the IC. The next potentiometer is used to vary the signal amplitude, then it is fed to amplifier stage built around IC LA4440, it is a two channel audio power amplifier with inbuilt dual channels for stereo and bridge amplifier applications. In dual mode the IC LA4440 gives 6W, where as in bridge mode it provides 19W. It has good ripple rejection of 40dB, small residual noise, built in over voltage and surge voltage protection, and pin to pin protection. The RF reception and performance of the circuit is dependent on many...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
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The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
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This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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