EmerGency Chargers For Mobiles From Telephone Connection's

I am going to explain how to TAP Telephone Connection For Charging Mobile Phones..Normaly,  Mobile phone Battery is made up of Lithium-ion(LI-ion) Capacity of 3.7v(Many battery capacity varies depends on Mobile phones).

**Nowdays each and every houses,companies Have Telephone connections,i am going to say how to charge the mobile phones During Power failures..

Normaly,Telephone Communication Need Power to Transmit a Signals or Voice message from one Telephone to another Telephone.During call a transmission station is need to send And receive signals.

During Transmission,Electric Charges is needed for Communication,So transmission station Send the signal with electric charge of  50v to 60v with 628ohms..Its Enough for Charging A mobile Phone.WHenever,power failure in Telecphone Exchange They Use A Back Up called Generator..

CONSTRUCTION

MATERIAL's NEEDED

*A voltage regulator( IC LM7805 - Downs to 5v)

*A Usb Cable with FEMALE PLUG

*A Usb To connect Mobile Phones

*Phone Card

 

Connections Should Be Done With Following Ciruit Diagram

Solder All the COnnection Properly!! The IC cost Only rs.10/ only.

Connections Which i made

(i)

 (ii)-Connecting The IC LM7805

 (iii)-Connecting To TelePhone Router

 (iv)-Charging

Guys,I hope This Information Is Valueable For Peoples Living in TamilNadu..

Post Ur Comment If U Have Doubts

THANKING YOU..See U soon in Next Experiment..!!

 

TELEVISION REMOTE FOR CONTROLLING HOME APPLIANCES

As a engineer we should use small resources for big application.

Now,i am going to post about controlling a Home appliances using Television Remote.

Television remote uses infared rays for the transmission of signals from remote to Television.

For this you dont need any programing skills etc.Only you should have electronics skills

 

ELOBORATION OF CIRCUIT

*Connect any four Appliances in your home (Fan,radio,light etc).

*Remote of tv,vcd,dvd players can be used for turning on-off the appliances.

*The 38kHz infrared (IR) rays generated by the remote control are received by IR receiver module TSOP1738 of the circuit.

*Pin 1 of TSOP1738 is connected to ground, pin 2 is connected to the power supply through resistor R5 and the output is taken from pin 3. The output signal is amplified by transistor T1 (BC558).

*The amplified signal is fed to clock pin 14 of decade counter IC CD4017 (IC1). Pin 8 of IC1 is grounded, pin 16 is connected to Vcc and pin 3 is connected to LED1 (red), which glows to indicate that the appliance is ‘off.’

*The output of IC1 is taken from its pin 2. LED2 (green) connected to pin 2  is used to indicate the ‘on’ state of the appliance.

*Transistor T2 (BC548) connected to pin 2 of IC1 drives relay RL1. Diode 1N4007 (D1) acts as a freewheeling diode.

*The appliance to be controlled is connected between the pole of the relay and neutral terminal of mains. It gets connected to live terminal of AC mains via normally opened (N/O) contact when the relay energises.

CIRCUIT DIAGRAM

FM BUG

This FM bug transmitter circuit will let you spy on people. The transmitter can be placed in the desired room and the conversation heard from a place far away just using a regular FM radio set.

EXPLANATION

*The circuit is designed around a single transistor 2N3904 (T1), a custom-made coil (L1), three capacitors (C1 through C3), a trimmer (VC1), two resistors (R1 and R2) and, of course, a condenser microphone (MIC1). 

*The circuit transmits in the frequency range of 88-105 MHz. Transmission range is 100 metres.

*Working of the circuit is simple and based on analogue modulation in which a carrier signal is varied corresponding to the message signal.

 

*The microphone picks up the sounds in its vicinity to produce corresponding electrical signal. This is the message signal that needs to be transmitted over FM band. The message signal is fed to the base of transistor T1. 

*The tank circuit made using trimmer VC1 and coil L1 generates the carrier frequency. This frequency can be tuned using the trimmer. Transistor T1 modulates the audio signal from condenser microphone over the carrier signal produced by tank circuit. This modulated signal is transmitted through the antenna (ANT.).

*Using trimmer VC1, tune the carrier frequency in FM band and confirm it with an oscilloscope. You will hear the conversation picked up by MIC1 when you tune frequency of the FM radio set to match frequency of the carrier.

*Prepare the coil L1 using about 25cm length of 25SWG wire. Wrap the wire around a cylindrical object of 6mm diameter and take it out after eight turns.

MOTION SENSOR BASED LIGHTING SYSTEM

Nowdays,people are afraid to go out in their home at night,This includes children too.For that they want to go and search for the light switch and switch it ON.

For that i came with a model going to post is MOTION SENSOR BASED LIGHTING SYSTEM.

It gets on when we walk near that sensor.

EXPANSION

*Here is a system based on PIR motion detector module BS1600 (or BS1700) that can be used for security or corridor lighting in power-saving mode. 

*The 12V DC power supply required for the motion detector and the relay driver is derived from 230V, 50Hz mains using a transformerless circuit.

*The working of the circuit is simple. When you power-on the circuit after assembling all the components including the CFL, the CFL will glow for 10 seconds, turn off for 30 seconds, glow for 10 seconds and then turn off. Now the circuit is ready to work.

WORKING

*When any movement is detected, around 3.3V appears on the base of relay-driver transistor T1 and it conducts to energise relay RL1. As a result, Triac1 (BT136) fires to provide full 230V and light up the CFL. 

*Another normally-opened contact of the relay (N/O2) is used here to hold the output until reset. If the switch is not in 'hold' position, the light will remain 'on' for about ten seconds (as programmed in the motion sensor). In short, when there is a movement near the sensor, the CFL glows for about ten seconds. It will remain 'on' if switch S1 is in 'hold' position.

CIRCUIT DIAGRAM

METAL DECTECTOR USING DIFFERENCE RESONATOR

Hai Friends..!!

Nowdays,In Bus stands,Railway station,Air-port using Metal dectector for the purpose for seeking explosive material.

People are much interseted to know their working system.

Now i am going to post a article METAL DECTECTOR USINHG DIFFERENCE RESONATOR.

It can be done in small scale and need some electronics skills to design and execute this circuit

DESIGN AND WORKING

*This is a simple circuit that can detect metallic conductors in its vicinity up to a range of 25 to 30 millimetres. Concealed metallic objects such as metal foils enclosed in a plastic cover. However, very thin metallic foils may go undetected due to a large resistance.

*The circuit is based on the principle of a difference resonator and consists of inverters, detector coils, capacitors and transistors.

* Fix the refill on a base (support), such as a small general-purpose PCB, using glue. Fix the gel-pen refill PCB on one end of a 50gm solder wire bobbin such that the refill is in the centre of the bobbin. Coil L3, having 200 turns of 25SWG (0.5mm diametre) enameled copper wire, is wound on the solder wire bobbin.

*Varying magnetic field produced in coil L3 induces current in coils L1 and L2. Coils L1 and L2 in series form a difference resonator along with capacitor C1. Coil L3 itself is made to resonate by driving it with a square-wave signal at a frequency approximately equal to the resonance frequency of the L-C circuit formed by outer coil L3 and capacitor C2.

*The square wave is generated by the oscillator formed by gates N1 and N2 (IC CD4069). Gates N3 through N6 act as buffers to drive outer coil L3. This produces sinusoidal current in coil L3, producing sinusoidal magnetic field mutually coupling the inner two coils.

*When a metal (conductor) is brought near one of the inner coils, say L1, the Eddy currents in the conductor reduce the magnetic flux in coil L1, reducing the induced electromotive force (emf).

*This means a difference-signal is produced by the two coils due to the presence of a conducting object (metal) near coil L1 as shown in the circuit.

*Coils L1 and L2 are connected such that the difference of the induced emf is fed to transistor T1 through capacitor C4. Transistor T1 is configured as a small signal amplifier.

*The amplifier is biased using a large base resistor of 1 mega-ohm. The AC-difference signal directly appears across the base-emitter junction of transistor T1 producing changes in the emitter current.

*This results in a voltage change in the collector of T1, which drives transistor T2 to glow LED1.

*A small signal produced due to the magnetic field of Eddy currents in a small piece of metal like a screw or nut is sufficient to trigger T2 through T1.

*Normally, the ferrite rods within coils L1 and L2 are adjusted such that the difference-signal from them is minimum. In this particular design, it is possible to adjust the signal to a voltage as small as 5 mV of sine wave.

*Transistor T2 plays the role of an electronic switch to drive LED1, which acts as a visual indicator whenever the metal is detected.

*Thus when the detector assembly is brought close to a conductor, LED1 glows. You can change capacitors C1 and C2 on trial-and-error basis and fix the value for maximum sensitivity to select a resonant frequency and drive the oscillator (N1 and N2) at that frequency. Here a frequency of 55 kHz has been selected.

CONSTRUCTION AND MODELLING

* Terminate all the four terminals of the coils on the PCB base for connecting the coils to the main circuit.

*The gel-pen refill should be sufficiently rugged. Secure it firmly inside the bobbin using non-magnetic, non-conducting materials.

*The ferrite rods too must be sufficiently secured in their positions using a synthetic enamel. Even a slight unintentional displacement can upset the balance of the resonator drastically. So use of a screw-type ferrite rod is recommended.

CIRCUIT DIAGRAM

MICRO INVERTER AT HOME

Nowdays,peoples are suffering from frequent power failure,Many old-age peoples are much worried due to power-cut because their body condition need some relaxation by air etc.

To overcome this problem,i Am going to post a model MICRO INVERTER in 12v dc can be converted into 240v.

DESIGN AND WORKING

* A simple low-power inverter circuit is described here, which converts 12V DC into 230V AC. It can be used to power very light loads like night lamps and cordless telephones,but can be modified into a powerful inverter by adding more MOSFETs.

* This circuit has two stages-battery charger with cut-off, and battery level indicator and inverter circuit.Charging circuit is built around IC1 (LM317).

 

*When mains 230V AC is available, IC1 provides gate voltage to SCR1 (TYN616) through diode D3 (1N4007). SCR1 starts charging the battery. 

* The battery level indicator and inverter circuit. The battery level checking system is built around transistors T1 and T2 (both BC547) along with some discrete components. 

*When the battery is charged (say, to more than 10.50V), LED1 glows and piezo-buzzer PZ1 does not sound. On the other hand, when battery voltage goes down (sayk, below 10.50V),LED1 stops glowing and piezo-buzzer sounds, indicating that the battery has been discharged and needs recharging for further use.

*The inverter is built around IC2 (CD4047), which is wired as an astable multivibrator operating at a frequency of around 50 Hz. The Q and Q outputs of IC2 directly drive power MOSFETs (T3 and T4). The two MOSFETs (IRFZ44) are used in push-pull configuration. The inverter output is filtered by capacitor C1

.

*The circuit on a general-purpose PCB and enclose it in a suitable metal box. Mount the transformer on the chassis and the battery in the box using supporting clamps. Use suitable heat-sinks for MOSFETs.

* The circuit can be used for other applications as well by delivering higher power with the help of a higher current rating transformer and additional MOSFETs.  

BATTERY CIRCUIT

 

 

CIRCUIT DIAGRAM

  

AUTOMATIC STREET LIGHT ON AND OFF

Do you people knows how the street light will SWITCH on/off.It is little hard but if we understood the logical it is easy to construct.In Olden Days street light will be switched on/off by a person.Now due to new technology Sensor is used to switch ON / OFF street light.

Now i will post this as follows

CIRCUIT DIAGRAM

*The circuit diagram present here is that of a street light that automatically switches ON when the night falls and turns OFF when the sun rises. 

*In fact you can this circuit for implementing any type of automatic night light.

*The circuit uses a Light Dependent Resistor (LDR) to sense the light .When there is light the resistance of LDR will be low. 

*So the voltage drop across POT R2 will be high.This keeps the transistor Q1 ON. The collector of Q1(BC107) is coupled to base of Q2(SL100). So Q2 will be OFF and so do the relay. The bulb will remain OFF.

*When night falls the resistance of LDR increases to make the voltage across the POT R2 to decrease below 0.6V. This makes transistor Q1 OFF which in turn makes Q2 ON. The relay will be energized and the bulb will glow.

NOTES

*R2 can be used to adjust the sensitivity of the circuit.

*You can use bulb of any wattage, provided that relay should have the sufficient rating.

*The circuit can be powered from a regulated 9V DC power supply.

CIRCUIT DIAGRAM