Cell phone Caling Detector Circuit Diagram

This is the Cell phone Caling Detector Circuit Diagram. In this detector when Flashes a LED when detecting an incoming callPowered by one 1.5V cell . This circuit 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.

Cell phone Caling Detector Circuit Diagram

Circuit operation:

The signal detected by the sensor coil is amplified by transistor Q1 and drives the monostable input pin of IC1. The IC's output voltage is doubled by C2 & D2 in order to drive the high-efficiency ultra-bright LED at a suitable peak-voltage.

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.)

Notes:

Stand-by current drawing is less than 200µA, therefore a power on/off switch is unnecessary.

Sensitivity of this circuit 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.

author: RED Free Circuit Designs

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Simple calling Detector Circuit Diagram

This is the Simple phone calling Detector  Circuit Diagram. Flashes a LED when detecting an incoming call. Powered by one 1.5V cell

Device purpose:
This circuit 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.

 Simple calling Detector  Circuit Diagram

Circuit operation:
The signal detected by the sensor coil is amplified by transistor Q1 and drives the monostable input pin of IC1. The IC's 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 circuit 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.

Sourced By: RED Free Circuit Designs

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Resistance ratio Detector Circuit Diagram

This is the Simple Resistance ratio Detector Circuit Diagram.  Photoelectric control, temperature detection and moisture sensing require a circuit that can accurately detect a given resistance ratio. A simple technique that uses an op amp as a sensing element can provide 0,5% accuracy with low parts cost. The reed-relay contacts close when the resistance of the sensor Rp equals 47% of the standard Rs.

 Simple Resistance ratio Detector Circuit Diagram

Adjusting either Rl or R2 provides a variable threshold; the threshold is controlled by varying R3. For the most part, the type of resistors used for Rl and R2 determines the accuracy and stability of the circuit. With metal-film resistors, less than 0.5% change in ratio sensing occurs over the commercial temperature range (0 to 70 C) with ac input variations from 105 to 135 V.Link

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Simple Rf Output Indicator Circuit Diagram

This is the Simple Rf Output Indicator Circuit Diagram. In this electronic circuit A simple RF detector circuit using a visual indicator can be useful for an RF output indicator, etc. This circuit was used for a transmitter ON indicator. 

Simple Rf Output Indicator Circuit Diagram

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Infrared Proximity Detector Circuit Diagram

This proximity detector using an infrared detector (Fig. 1) can be used in various equipment like automatic door openers and burglar alarms. The circuit primarily consists of an infrared transmitter and an infrared receiver.

Fig. 1: IR proximity detector

The transmitter section consists of a 555 timer IC functioning in astable mode. It is wired as shown in the figure. The output from astable is fed to an infrared LED via resistor R4, which limits its operating current. This circuit provides a frequency output of 38 kHz at 50 per cent duty cycle, which is required for the infrared detector/receiver module. Siemens SFH5110-38 is a much better choice than SFH506-38. Siemens SFH5110-38 is turned on by a continuous frequency of 38 kHz with 50 per cent duty cycle, whereas SFH506 requires a burst frequency of 38k to sense. Hence, SFH5110-38 is used.

The receiver section comprises an infrared receiver module, a 555 monostable multivibrator, and an LED indicator. Upon reception of infrared signals, 555 timer (mono) turns on and remains on as long as infrared signals are received. When the signals are interrupted, the mono goes off after a few seconds (period=1.1 R7xC6) depending upon the value of R7-C6 combination. Thus if R7=470 kilo-ohms and C6=4.7µF, the mono period will be around 2.5 seconds.

Fig. 2: Proposed arrangement for separation of IR LED and receiver module in the proximity detector

Both the transmitter and the receiver parts can be mounted on a single breadboard or PCB. The infrared receiver must be placed behind the infrared LED to avoid false indication due to infrared leakage.

An object moving nearby actually reflects the infrared rays emitted by the infrared LED. The infrared receiver has sensitivity angle (lobe) of 0-60 degrees, hence when the reflected IR ray is sensed, the mono in the receiver part is triggered. The output from the mono may be used in any desired fashion. For example, it can be used to turn on a light when a person comes nearby by energising a relay. The light would automatically turn off after some time as the person moves away and the mono pulse period is over.

The sensitivity of the detector depends on current-limiting resistor R4 in series with the infrared LED. Range is approximately 40 cm. For 20-ohm value of R4 the object at 25 cm can be sensed, while for 30-ohm value of R4 the sensing range reduces by 22.5 cm.

(Note. The author procured the samples of Siemens products from Arihant Electricals, New Delhi, the distributor of Siemens in India.)

This circuit costs around Rs 125.

Sourced By: EFY Author :  K.S. Sankar

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Simple Metal Pipe Detector Circuit Diagram

This is the Simple Metal Pipe Detector Circuit Diagram. The metal detector Future is a detection instrument to locate steel pipelines, gas pipes, water pipes as well as voids and cavity under the ground surface. This circuit uses a 15-kHz oscillator coil. When metal placed in the energy field is withdrawn, the oscillator voltage is rectified and compared to a reference. A drop in oscillator voltage therefore operates comparator IC2 and 1)4 (LED) extinguishes.

Simple Metal Pipe Detector Circuit Diagram

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Metal Detector Circuit using 4011

 I love the detector , this is actually one of my Hobby's, want to know more you saw the blog Metal Detector, there is lots of interesting information. But when we circuit the principle of operation of this detector circuit home metal consists of a mixture of two equal frequency causing interference. When one of the oscillators become unstable, the frequency of the interference is modified by changing the tone, so alert the user to the presence of a conductive metal near the coil.

Metal Detector cheap and easy to build

This detector is cheap and easy to build , requires neither a printed circuit and can be tested directly over a breadboard . It is constructed using principal components as a transistor and a CMOS integrated circuit 4011 .

 The integrated circuit 4011

The integrated circuit 4011 consists of four NAND gates with two inputs each clock frequency depends on its supply voltage but reaches a maximum 10 MHz It operates in a recommended range of 3 V to 15 V supply range .

The operation of the Metal Detector

The oscillator is built with NAND gate N1 and a ceramic filter intermediate frequency ( IF) of 470kHz is used in this oscillator. The second oscillator was built with NAND gate N3 and an LC circuit (coil + capacitor) . The frequency of the second oscillator is adjusted such that it will produce an audible oscillation frequencies of both , hence the name of this type of metal detector BFO ( Beat Frequency Oscillator ) .

The setting of this oscillator is done through the variable capacitor , you should adjust for parelhamento signals from two oscillators let the coil away from metals to prevent feedback . The signal from the second oscillator is amplified in the NAND gate N4 , mixed with the fixed oscillator in NAND gate N2 and amplified by the transistor again before going to the speaker .

If the sensor coil L1 get close to a metal object , this will modify the frequency of oscillation, causing the self - induction coil , unbalancing the frequency and consequently modifying the sound in the output. The metal detector coil L1, is made of 70 turns of enameled wire cover with diam . 0.3 to 0.6 mm and a diameter of 5 cm.

The Metal Detector

A metal detector is an electronic instrument that detects the presence of ferrous or non -ferrous metal nearby. Metal detectors are useful for finding metal objects hidden inside walls or buried in the soil . They usually consist of a portable unit with a sensing coil that can be swept on the ground or other objects .

If the coil approaches a metal piece will sound an alert indicated by a sound , an LED sign, or the oscillation of the galvanometer pointer . Typically, the device gives some indication of the distance when the metal is closest , which is a higher audio tone or higher level pointer.

Another common type of detectors are stationary detector. Metals are used for security screening at access points in prisons, banks, courts detectors, and airports, to detect metal weapons hidden in a person's body.

The first industrial metal detectors were developed in the 1960s and were widely used for mineral exploration and other industrial applications. Uses include de-mining (the detection of land mines), the detection of weapons such as knives and guns, geophysical prospecting, archeology and treasure hunting.

Metal detectors are also used to detect foreign bodies in food, and in the construction industry to detect steel reinforcing bars in concrete, tubes, pipes and wires buried in walls and floors.

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Electronic Line Current Detector Circuit Diagram

This is simple Electronic Line Current Detector Circuit Diagram. Detection of line-current flow and indicating the flow to an electrically remote point is required in line status monitoring at a variety of points in the telephone system and auxiliary systems. 

 Electronic Line Current Detector Circuit Diagram

The line should be minimally unbalanced or loaded by the monitor circuit, and relatively high levels of 60-Hz induced voltages must be ignored. The HllAAl allows line currents of either polarity to be sensed without discrimination and will ignore noise up to approximately 2.5 mA. In applications where greater noise immunity or polarity- sensitive line-current detection is required, the HllAlO threshold coupler can be used. 

This photo transistor coupler is specified to provide a minimum 10% current transfer ratio at a defined input current, while leaking less than 50 p.A at half that input current over the full -55°C to + 100°C temperature range. The input current range, at which the coupler is on, is programmable by a single resistor from 5 to 10 mA.

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Simple Proximity Detector Sensor Circuit Diagram

A proximity sensor is a sensor able to detect the presence of nearby objects without any physical contact. This simple circuit is actuated by an increase in capacitance between a sensing electrode and the ground side of the line. The sensitivity can be adjusted to switch when a human body is within inches of the insulated plate used as the sensing electrode. Thus, sensitivity is adjusted with the 1 meg ohm potentiometer which determines the anode voltage level prior to clamping This sensitivity will be proportional to the area of the surface opposing each other.

Simple Proximity Detector Sensor Circuit Diagram

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This is the simple Schmidt trigger zero crossing detector circuit diagram. This circuit has a 100 mV hysteresis which can be used in applications where very fast transition times are required at the output even though the signal is very slow. The hysteresis loop also reduces false triggering due to noise on the input. The waveforms show the trip points developed by the hysteresis loop.

Zero Crossing Detector Circuit Diagram

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Simple Bug Detector Circuit Diagram

Simple Bug Detector Circuit Diagram. This circuit is a best security circuit diagram. This is a Simple Bug Detector Circuit Diagram, This rf detector can locate low-power transmitters (bugs) that are hidden from sight. It can sense the presence of a 1-mW transmitter at 20 feet. which is sensitive enough to detect the tiniest bug. As you bring the rf detector closer to the bug, more and more segments of its LED bar-graph display light, which aids in direction finding. 

Simple Bug Detector Circuit Diagram

 

The front end has a two-stage wide-band rf amplifier, and a forward-biased hot-carrier diode for a detector. After detection, the signal is filtered and fed to IC1, an LM3915N bar-graph driver having a logarithmic output. Each successive LED segment represents a 3-dB step.

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Simple Power Failure Detector Circuit Diagram

Simple Power Failure Detector Circuit Diagram. This circuit indicates that a power outage occurred for 1, 10, 100, and 500 seconds with the values given for R* and C* . After a power failure, the circuit can be reset by pushing the Reset button.

Simple Power Failure Detector Circuit Diagram

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