The warehouse needs more room to accommodate more Cell Phone Jammers .
Intelligently find nearby gas stations, restaurants, supermarkets and parking lots. In the long-distance travel in the car, no longer have to ask how to get high-speed ahead, out of which the intersection, as long as the marked destination, set the priority to high-speed road, will help you plan out where you want to go the best route. Such as Xinjiang from Beijing to self-driving tour, you can enter Urumqi. The warehouse of Cell Phone Jammers is near the subfactory.
When you deviate from the route has been selected, will prompt you off course, and it will automatically re-plan your route. The current map, there are more than 400 cities in the country a detailed map, a small county-level cities have, as well as the countrys highway network detailed map, as well as tourist zones, mountain maps. Mainly in travel, hiking, picnic, etc., when used to plan routes, indicating position, record tourist track. You can climb a Piedmont, mountain climbing using the previous track. GPS devices have the track record of features, such as Guilin, or you want to self-driving tour of Tibet, you can download someone elses track, then do not ask for directions, directly under the flight path travel. The warehouse of Cell Phone Jammers will be closed at four o’clock.
IE browser produced by Microsoft, a browser, and using free (and Win) bundled manner to the user, that is, as long as you use the Win family of operating systems would certainly have the IE browser, but also because So, IE has occupied the vast majority of personal computer browser share, other non-IE (core) browser such as Netscape NETSCAPE, OPERA and FIREFOX also individual users in general are rare. Is a low-power short-range wireless connectivity technology standard in lieu of that, "Bluetooth" is taken from a unified in the 10th century Danish king, Harald II, (Harald) of the nickname, the "Bluetooth" (Bluetooth). "Bluetooth" technology is the first five world-renowned advocate of computer and communications companies: Ericsson, Ericsson, International Business Machines IBM, Intel, Intel, Nokia Nokia, and Toshiba Toshiba. And in May 1998 set up a "Bluetooth" special interest group (Bluetooth Special Interest Group-SIG), the organization adopted a free transfer to industry of the patented technology strategy to achieve its goal of global harmonization of standards. The worker needs to get the needed Cell Phone Jammers before it is closed.
The goal is to achieve maximum data transfer speed 1Mbps (the effective transmission speed of 721kbps), the maximum transmission distance of 10 meters, the user can not have been allowed to use the 2.4GHz ISM (industrial, scientific, medical) band, set up in its 79 channel bandwidth of 1MHz, with a frequency of 1,600 times per second switching, hobbing (hobbing) mode technology to achieve spread spectrum radio transceiver. This is the origin and characteristics of Bluetooth technology. Bluetooth technology to communicate with the equipment, determine the frequency roll into gear mode "caller" and its communication opponent, "by taking sides." Caller before they take the same time by the parties and seven communication. Therefore, the caller can be taken together with the seven parties were famous for the 8 devices to connect Piconet (sawtooth network) subnet. Piconet taken by the parties within the same time as the subject to take more than two parties Piconet. In July 1999, announced the official Bluetooth specification BluetoothVersion 1.0. Comply with the specifications of cell phones and laptop computers will be listed in late 1999 or early 2000. Bluetooth technology products make claims that the companies are growing, the current Bluetooth standards bodies "BluetoothSIG (Special Interest mix)" members of the enterprises has increased to 800 or more.

We are surrounded by battery operated equipment of all kinds, and this array is growing still. Manufacturers and designers lean over backwards to make sure that their equipment draws a small current and can thus be operated by a battery. This has its flip side, too. because even if the equipment in question draws only a small current, when it is not switched off, the battery is flat after a few days or weeks. The circuit presented here can prevent this happening. It may be added to all kinds of equipment operating from a 9 V battery and switches this off automatically one minute after a preset time has elapsed. The peak switching current is 20 mA, which is more than enough for most applications.

The switch is formed by a p-n-p darlington, T1, which is actuated by push-button switch S1. The very high amplification of the darlington enables it to be kept on fairly long with the aid of a relatively small-value capacitor, C1 (= 100 µF). Resistor R3 limits the charging current of C1 to ensure a long life of S1. Resistors R1 and R2, in conjunction with C1, determine the switch-on time. When this time has elapsed, R1 ensures that T1 is switched off. Since the darlington can handle a UBE of –10 V, a polarity protection diode is not needed.

The battery discharger published in this website may be improved by adding a Schottky diode (D3). This ensures that a NiCd cell is discharged not to 0.6–0.7 V, but to just under 1 V as recommended by the manufacturers. An additional effect is then that light-emitting diode D2 flashes when the battery connected to the terminals is flat. The circuit in the diagram is based on an astable multivibrator operating at a frequency of about 25 kHz. When transistor T2 conducts, a current flows through inductor L1, whereupon energy is stored in the resulting electromagnetic field. When T2 is cut off, the field collapses, whereupon a counter-emf is produced at a level that exceeds the forward voltage (about 1.6 V) of D2.

A current then flows through the diode so that this lights. Diode D1 prevents the current flowing through R4 and C2. This process is halted only when the battery voltage no longer provides a sufficient base potential for the transistors. In the original circuit, this happened at about 0.65 V. The addition of the forward bias of D3 (about 0.3 V), the final discharge voltage of the battery is raised to 0.9–1.0 V. Additional resistors R5 and R6 ensure that sufficient current flows through D3. When the battery is discharged to the recommended level, it must be removed from the discharger since, in contrast to the original circuit, a small current continues to flow through D3, R2-R3, and R5-R6 until the battery is totally discharged.

The flashing of D2 when the battery is nearing recommended discharge is caused by the increasing internal resistance of the battery lowering the terminal voltage to below the threshold level. If no current flows, the internal resistance is of no consequence since the terminal voltage rises to the threshold voltage by taking some energy from the battery. When the discharge is complete to the recommended level, the LED goes out. It should therefore be noted that the battery is discharged sufficiently when the LED begins to flash.

No complex switching required, Simple circuitry, 6-12V supply

This design allows to operate two intercom stations leaving the operator free of using his/her hands in some other occupation, thus avoiding the usual "push-to-talk" operation mode. No complex changeover switching is required: the two units are connected together by means of a thin screened cable. As both microphones and loudspeakers are always in operation, a special circuit is used to avoid that the loudspeaker output can be picked-up by the microphone enclosed in the same box, causing a very undesirable and loud "howl", i.e. the well known "Larsen effect". A "Private" switch allows microphone muting, if required.

Circuit Diagram :

Full-duplex Intercom Circuit diagram

Parts:

P1_____________22K Log. Potentiometer
R1_____________22K 1/4W Resistor
R2,R3_________100K 1/4W Resistors
R4_____________47K 1/4W Resistor
R5______________2K2 1/4W Resistor (See Notes)
R6______________6K8 1/4W Resistor
R7_____________22K 1/2W Carbon or Cermet Trimmer
R8______________2K7 1/4W Resistor
C1,C6_________100nF 63V Polyester or Ceramic Capacitors
C2,C3__________10µF 63V Electrolytic Capacitors
C4_____________22µF 25V Electrolytic Capacitor
C5_____________22nF 63V Polyester or Ceramic Capacitor
C7____________470µF 25V Electrolytic Capacitor
Q1____________BC547 45V 100mA NPN Transistor
IC1_________TDA7052 Audio power amplifier IC
SW1____________SPST miniature Switch
MIC____________Miniature electret microphone
SPKR___________8 Ohm Loudspeaker
Screened cable (See Text)

Circuit operation:

The circuit uses the TDA7052 audio power amplifier IC, capable of delivering about 1 Watt of output power at a supply voltage comprised in the 6 - 12V range. The unusual feature of this design is the microphone amplifier Q1: its 180° phase-shifted audio output taken at the Collector and its in-phase output taken at the Emitter are mixed by the C3, C4, R7 and R8 network and R7 is trimmed until the two incoming signals almost cancel out. In this way, the loudspeaker will reproduce a very faint copy of the signals picked-up by the microphone.

At the same time, as both Collectors of the two intercom units are tied together, the 180° phase-shifted signal will pass to the audio amplifier of the second unit without attenuation, so it will be loudly reproduced by its loudspeaker. The same operation will occur when speaking into the microphone of the second unit: if R7 will be correctly set, almost no output will be heard from its loudspeaker but a loud and clear reproduction will be heard at the first unit output.

Notes:

• The circuit is shown already doubled in the diagram. The two units can be built into two separate boxes and connected by a thin screened cable having the length desired.
• The cable screen is the negative ground path and the central wire is the signal path.
• The power supply can be a common wall-plug adapter having a voltage output in the 6 - 12V dc range @ about 200mA.
• Enclosing the power supply in the box of one unit, the other unit can be easily fed by using a two-wire screened cable, its second wire becoming the positive dc path.
• To avoid a two-wire screened cable, each unit may have its own separate power supply.
• Please note that R5 is the only part of the circuit that must not be doubled.
• Closing SW1 prevents signal transmission only, not reception.
• To setup the circuit, rotate the volume control (P1) of the first unit near its maximum and speak into the microphone. Adjust Trimmer R7 until your voice becomes almost inaudible when reproduced by the loudspeaker of the same unit.
• Do the same as above with the second unit.

Source : www.redcircuits.com

If you want to connect a video signal to several destinations, you need a distribution amplifier to match the 75-ohm video cable. A distribution amplifier terminates the incoming cable in 75 ohms and provides several outputs, each with 75-ohm output impedance. Since this is usually achieved by putting a 75-ohm series resistor in the output lead of each video opamp (current-feedback amplifier), the opamps must be set up for a gain of 2 in order to achieve an insertion gain of 1 (0 dB). The disadvantage of this arrangement is that if the amplifier or its power supply fails, no signal is available at any of the outputs. This can be remedied by using a high input impedance amplifier, which can be tapped into a video line without having to have its own 75-ohm termination resistor.

 

In order to eliminate hum interference and voltage differences between the cable screen and the circuit earth, the circuit exploits the common-mode rejection of the opamp. This can be optimized with resistor RG1. With the indicated LT1396 video opamp, more than 40 dB of common-mode rejection can be achieved. The signal bandwidth of the circuit can be optimized using the trimpots. It reaches to more than 10 MHz, which is quite acceptable for video signals. Thanks to the high-impedance connection to the video line, the video signal is not affected when the power for the coupled amplifier is switched off. You can learn more about the LT1396 from its data sheet at http://www.linear-tech.com.

Parallax, well known for its successful Basic Stamp IC, has recently introduced the Propeller: a new microcontroller with a certain difference. It packs no less than eight 32-bit processors (referred to as COGs in Propeller jargon) into a single package with only 40 pins. That design takes genuine simultaneous multiprocessing possible, and the sophisticated internal structure of the device makes it relatively easy to implement video and signal-processing applications. The Propeller can be programmed in assembly language or the high-level Spin language. The processor and the programming tools were developed entirely in-house by Parallax, with the hardware being designed from scratch starting at the transistor level.

Circuit diagram:

Programming The Propeller IC Circuit Diagram

The basic idea behind that was to avoid becoming involved in all sorts of patent disputes with other manufacturers. The result is astounding, and for software developers it certainly requires a change in mental gears. As is customary with modern microprocessors, the Propeller has a simple serial programming interface. The developer’s toolkit from Parallax has a modern USB port for that purpose, but a reasonably simple alternative (illustrated here) is also possible for anyone who prefers to work with the familiar RS232 port. Don’t forget that the Propeller works with a 3.3-V supply voltage.

Copyright: Elektor Electronics

More and more electronic devices are portable and run off batteries. It is no surprise, then, that so many flat batteries find their way into the bin - and often far too early. When a set of batteries can no longer run some device - for example, a flashgun - the cells are not necessarily completely discharged. If you put an apparently unserviceable AA-size cell into a radio-controlled clock with an LCD display it will run for months if not years. Of course not every partially discharged cell can be put in a clock. The circuit presented here lets you squeeze the last Watt-second out of your batteries, providing a bright ‘night light’ - for free!

The circuit features a TBA820M, a cheap audio power amplifier capable of operating from a very low supply voltage. Here it is connected as an astable multivibrator running at a frequency of around 13 kHz. Together with the two diodes and electrolytic capacitor this forms a DC-DC converter which can almost double the voltage from between four and eight series-connected AA-, C- or D-size cells, or from a PP3-style battery. The DC-DC converter is followed by a constant current source which drives the LED. This protects the expensive white LED: the voltages obtained from old batteries can vary considerably.

With the use of the DC-DC converter and 20 mA constant current source a much greater range of usable input voltages is achieved, particularly helpful at the lower end of the range when old batteries are used. With the constant current source on its own the white LED would not be adequately bright when run from low voltages. An additional feature is the ‘automatic eye’. The LDR detects when the normal room lighting is switched on or when the room is lit by sunlight: its resistance decreases. This reduces the UBE of the transistor below 0.7 V, the BC337 turns off and deactivates the LED.

This prolongs further the life of the old batteries. A further LDR across capacitor C reduces the quiescent current of the circuit to just 4mA (at 4V). Light from the white LED must of course not fall on the LDR, or the current saving function will not work.

This audio peak detector allows a pair of stereo channels to be monitored on a single LED. Identical circuitry is used in the left and right channels. Use is made of the switching levels of Schmitt trigger NAND gates inside the familiar 4093 IC. The threshold level for gate IC1.A (IC1.B) is set with the aid of preset P1, which supplies a high impedance bias level via R2 (R1). When, owing to the instantaneous level of the audio signal superimposed on the bias voltage by C3 (C2), the dc level at pins 1 and 2 (5 and 6) of the Schmitt trigger gate drops below a certain level, the output of IC1.A (IC1.B) will go High.


This level is copied to the input of IC1.C via D2 (D1) and due to the inverting action of IC1.C, LED D3 will light. Network R3-C1 provides some delay to enable very short audio peaks to be reliably indicated. Initially turn the wiper of P1 to the +12 V extreme — LED D3 should remain out. Then apply ‘line’ level audio to K1 and K3, preferably music with lots of peaks (for example, drum ‘n bass). Carefully adjust P1 until the peaks in the music are indicated by D3. The circuit has double RCA connectors for the left and right channels to obviate the use of those rare and expensive audio splitter (‘Y’) cables.

One of the author’s physics projects required an accurate 1-Hz (seconds) clock signal. Unfortunately, precision 10-MHz quartz crystals are expensive, while another problem was found in the inability of most common or garden 40xx CMOS logic chips to work at such a high frequency. However, a typical CMOS counter like the 4017 has such a high input resistance that its clock input has ‘radio’ properties.

Circuit diagram :

Isolated 1-Hz Clock Circuit Diagram

The effect is exploited here to convert the stray magnetic field picked up from a mains transformer into a clock signal. Here, the signal is induced in a short piece of wire (approx. 5 cm) connected to the clock input of a CD4017 decade counter for division by 10. The resulting 5-Hz signal is then divided by 5 by a second 4017 (IC2) to give an output of 1 Hz. LED D1 flashes to indicate the presence of a sufficiently strong magnetic field. The pickup wire should be placed close to the mains transformer, without compromising electrical safety. Always use the greatest distance at which a clock signal is reliably generated. For 1-Hz output from 60-Hz power systems, use output 6 of IC2 (pin 5).

Nowadays, just about every house has an outside lamp with a motion sensor. Such a device eliminates the need to feel your way to the front door, and it apparently also scares away intruders. The only problem is that free-running dogs and cats in the neighborhood have little regard for such lamps and continue to deposit their excrement in the garden, once they have found a habitual location there for this purpose. This gave rise to the idea of connecting a sort of siren in parallel with the outside lamp to clearly advise dogs and cats that they are not welcome.

Naturally, it would be nice to avoid startling the entire neighborhood with this alarm signal. Here we can take advantage of the fact that dogs and cats have a significantly better sense of hearing than people. Not only are their ears more sensitive, they can also perceive significantly higher frequencies. With people, the upper limit is around 18 kHz, but dogs and cats can hear frequencies in excess of 20 kHz. We can take advantage of this by building a siren that emits a frequency just above 20 kHz. This will scare off dogs and cats, but people will simply not hear it.

All we need for this is an oscillator with an amplifier stage and a tweeter that can reproduce such high frequencies, such as a piezoelectric tweeter. The schematic diagram shows how easily this can be implemented. The power supply for the entire circuit is formed by the components up to and including C2. The 230-V leads are connected in parallel with the motion-sensor lamp. C1 and R1 provide capacitive coupling to reduce the 230 V to an acceptable voltage. A DC voltage of approximately 9.1 V is generated from this voltage using a bridge rectifier and D1, filtered and buffered by C2. The oscillator is built around R3, C3 and IC1a.

The frequency of this oscillator is rather dependent on the specific characteristics of IC1, so the values shown here should be regarded as guidelines. If the oscillator frequency is too high, it can be reduced by increasing the value of R3 and/or C3. If the frequency is too low (which means that the siren tone it is audible), the value of R3 and/or C3 should be increased. The square-wave signal from the oscillator is applied to the input of an H bridge composed of several Schmitt triggers in combination with the final output stages (T1–T4). This approach causes the peak-to-peak value of the square wave signal to be twice the supply voltage.

As a result, a respectable 18 V is obtained across the piezoelectric tweeter, which is sufficient to produce a quite loud whistle tone. When building the circuit, you should bear in mind that it is directly powered from 230 V and not electrically isolated from the mains network. It is thus necessary to avoid contact with all of the components when the circuit is in use. In practice, this means that the circuit must be fitted into a well-insulated, waterproof box. If you want to test the circuit, it is a good idea to first discharge C1 using a resistor, since it can hold a dangerous charge. You must also ensure that components F1, C1, R1 and B1 all have a mutual insulation separation of at least 6 mm!

 AM Radio built around LM555 Circuit