Showing posts with label phone. Show all posts
Showing posts with label phone. Show all posts
Sunday, September 7, 2014
Cellular Phone calling Detector
This schema was designed to detect when a call is incoming in a cellular phone (even when the calling tone of the device is switched-off) by means of a flashing LED.The device must be placed a few centimeters from the cellular phone, so its sensor coil L1 can detect the field emitted by the phone receiver during an incoming call.
Parts:
R1____________100K 1/4W Resistor R2______________3K9 1/4W Resistor R3______________1M 1/4W Resistor C1,C2_________100nF 63V Polyester Capacitors C3____________220µF 25V Electrolytic Capacitor D1______________LED Red 10mm. Ultra-bright (see Notes) D2___________1N5819 40V 1A Schottky-barrier Diode (see Notes) Q1____________BC547 45V 100mA NPN Transistor IC1____________7555 or TS555CN CMos Timer IC L1_____________Sensor coil (see Notes) B1_____________1.5V Battery (AA or AAA cell etc.) The signal detected by the sensor coil is amplified by transistor Q1 and drives the monostable input pin of IC1. The ICs output voltage is doubled by C2 & D2 in order to drive the high-efficiency ultra-bright LED at a suitable peak-voltage. Notes: * Stand-by current drawing is less than 200µA, therefore a power on/off switch is unnecessary. * Sensitivity of this schema depends on the sensor coil type. * L1 can be made by winding 130 to 150 turns of 0.2 mm. enameled wire on a 5 cm. diameter former (e.g. a can). Remove the coil from the former and wind it with insulating tape, thus obtaining a stand-alone coil. * A commercial 10mH miniature inductor, usually sold in the form of a tiny rectangular plastic box, can be used satisfactorily but with lower sensitivity. * IC1 must be a CMos type: only these devices can safely operate at 1.5V supply or less. * Any Schottky-barrier type diode can be used in place of the 1N5819: the BAT46 type is a very good choice.
Friday, August 15, 2014
Simple Cell Phone Detector Wiring diagram Schematic
This is a simple cell phone detector schema diagram, this is a pocket-size mobile transmission detector or sniffer can sense the presence of an activated mobile cellphone from a distance of one and-a-half meters. 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.
Simple Cell Phone Detector Circuit Diagram
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