By Tommaso Panicciari, Mohamed Ali Soliman and Grégory Moura All images provided by the authors A real-time system combining a simulator and a GNSS propagation model reproduces an authentic multipath environment. The propagation model relies on a 3D-model reconstruction of the urban environment, which generates a multipath signature strictly dependent on the location of the receiver’s antenna. This yields important results for a moving vehicle, which may be affected by very different multipath conditions depending on trajectory and location. Positioning and navigation can be degraded in urban environments by multipath, and the error can increase considerably if not properly compensated. In situations where the line-of-sight (LOS) is obscured by surrounded buildings, the receiver may still be able to navigate by using the non-line-of-sight (NLOS) signal, which originates from single or multiple reflections/diffractions of the GNSS signal. The use of 3D models has been one of the preferred solutions to recreate the multipath environment as seen by a GNSS device. This solution brings the capability to generate a multipath signature that is representative of the position of the antenna in a specific time and space. However, this solution comes with a certain degree of complexity. In fact, an accurate 3D model is required to simulate the obscuration of the GNSS signal, and a good propagation model is needed to generate phenomena like reflection and diffraction. Figure 1. Example of propagated signal simulation. (Image: Tommaso Panicciari, Mohamed Ali Soliman and Grégory Moura))\ 3D models have become more accurate and widely available and are mainly used to predict the satellite availability in specific locations, for example in evaluating the signal availability in urban canyon, and for both reflection and diffraction. Other uses of 3D models are as an aiding tool to assist navigation, sometimes together with an INS solution. In this article, we present a novel real-time system capable of simulating realistic multipath in different environments. The system can simulate multiple GNSS constellations and is comprised of a GNSS simulator interfaced to a propagation model. The system can create a whole range of signals, effects, error models and trajectories in a real-time closed loop. The propagation model controls the simulation of multipath from the interaction of the GNSS signal with the 3D scene and objects. This article describes a novel real-time system for the simulation of realistic multipath in different environments and compares simulated and field-test data. The comparison is based on signal availability, horizontal error, carrier-to-noise (C/N0), pseudorange and Doppler residuals. RAY-TRACING WITH 3D MODELING The model simulates the propagation of GNSS signals in constrained environments, considering obscurations and multipath. It uses a proprietary ray-tracing kernel (based on bounding volume hierarchy techniques using processing unit [GPU] resources) coupled with geometrical optics and uniform theory of diffraction to compute the interaction between the signal and the local environment. The computation uses as main input a synthetic environment (that is, geometrical and physical modeling of a real or realistic environment) to assess the impact of obscurations related to signal availability issues and multipath (the cause of fading effects and performance problems). The objective of ray-tracing is to find all the possible paths from the observer to the source of the signal considering a limited number of interactions per emitted rays. A ray-tracer (or ray-tracing algorithm) uses a primary grid to cast primary rays. Then, it iteratively computes the possible interactions between these rays and the virtual scene (often defined using triangles). If those interactions exist (if they comply with the law of physics) and if the number of interactions to reach the emitter is below the maximum number of interactions set by the user, then a ray (or multipath) is created. This is a deterministic method that can be used to calculate the obscuration due to the local environment (and therefore detect the signal availability) and the geometrical characteristic of the computed path. Combined with physics modeling, path attributes such as received power, delay, Doppler, and phase are also provided. The main characteristics of ray-tracing techniques to model GNSS propagation are: All the signals arriving at the receiver can be model-based on the virtual environment. As it is a deterministic method, the more realistic the environment modeling, the more compliant with reality the results. Moreover, the simulation results are repeatable. The specular multipath can be displayed in 3D, and the attributes (for example, receiver power, phase, polarization, Doppler, geometry of the ray) are known. For example, this is relevant when the effect and signature of the environment on the propagation signal need to be studied and understood. Nonetheless, ray-tracing techniques must account for three major difficulties: They are time-consuming algorithms. Indeed, depending on the complexity of the scene (defined in terms of the number of triangles), a combinatorial problem to find the possible multipaths reaching the receiver makes the ray-tracer very resource-demanding. That is the reason why the most difficult task to achieve during the coding of a real-time ray-tracing algorithm is to develop acceleration techniques to quicken the computation process. Several solutions exist to either improve the intersection determination (for instance, based on spatial hierarchies such as bounding volume hierarchy [BVH] techniques), or to decrease the number of cast rays (often based on adaptive sampling techniques), or even to replace rays with beams or cones. Moreover, it is possible today to use the resources of graphic boards to accelerate the computation. Indeed, as ray-tracing can be coded by a large number of primary functions that can be treated simultaneously, it can be easily ported into GPU. Their accuracy depends on the resolution of the primary grid. Details and therefore rays may be missed if the 3D scene is made of small details. This issue is called aliasing. Aliasing artefacts are raised for instance in parts of the scene with abrupt changes (such as edges) or in complex areas with lots of constituent objects. Solutions (or antialiasing techniques) exist to overcome this issue such as adaptive or stochastic samplings. When it is combined with geometrical optics, these algorithms only compute the specular rays. Even if some techniques exist to model the scattering signals, only physical optics can render the global signal with high fidelity. MULTIPATH SIMULATION SYSTEM The proposed system can model two of the main propagation issues encountered in urban environments, such as obscuration (which leads to limitations in signal availability) and multipath (which generates interference that causes fading of the signal and positioning errors). To model realistically such a complex phenomenon, the system uses a GPU ray-tracing algorithm combined with geometrical optics and uniform theory of diffractions. The ray-tracing algorithm relies on 3D-model reconstructions of the urban environment. The computed obscuration and multipath effects are then used to generate signal corrections (in terms of power, delay and Doppler variation) to be used in the GNSS simulator, which generates the carrier, code and navigation messages for different GNSS constellations into a single RF output. Some of the advantages of this system is its ability to run in real time, and to visually show all the reflections/diffractions of the GNSS signals that cause multipath interference. Figure 2 shows the diagram of the system set up in conductive mode. The system includes a SE-NAV PC controller, simulator software suite controller, GNSS simulator and device under test (DUT). A different mode is also available called over the air (OTA). This mode uses an anechoic chamber and a set of antennas distributed uniformly to generate the RF signal including the multipath. The DUT can then be placed at the center of the chamber and will be able to receive LOS and NLOS signals from different angles of arrival. Figure 2. System diagram that shows propagation simulator controller (top), the GNSS simulator (bottom) and the device under test connected to the RF output of the simulator. (Image: Tommaso Panicciari, Mohamed Ali Soliman and Grégory Moura) The GNSS simulator software suite is used to generate and control the generation of the satellite signals (including multipath) at RF, whilst the propagation simulator is used to calculate the propagation information (delay, Doppler and attenuation) of the reflected signals through a 3D urban model. The propagation software is interfaced with GNSS simulator software by means of a package of remote-control facilities that greatly enhances the flexibility of the propagation simulator. Those commands can be sent and received through the transmission control protocol/use datagram protocol (TCP/UDP) with different data streaming rates (10 Hz was used for this article). It is also important to point out that the propagation simulator computes all the possible multipath signal generated by the 3D model given the position of the satellites and receiver. However, the physical limitation of the number of channels in the simulator causes the rejection of some rays. This rejection or filtering process can be done according to power (used in this article) or delay. EXPERIMENT SET-UP A set of different field-test campaigns where carried out in August 2016. Each campaign aimed to evaluate the ability of the system to assess the performances of a GNSS receiver using simulated signals in urban environments. Figure 3 shows the trajectory (blue line) used for the experiment in an urban environment — San Jose, California — with a static (a) and dynamic (b) scenario. Figure 3. A set of three measurement campaigns where carried out during Aug. 9–10, 2016: a) urban environment with static antenna; b) urban environment with dynamic antenna. (Image: Tommaso Panicciari, Mohamed Ali Soliman and Grégory Moura) Figure 4 shows the 3D scene used to replicate the San Jose urban environment. The buildings in close proximity of the antenna (green area in Figure 4b) contain details like material, 3D facade and windows. In contrast, the buildings far from the antenna were only corrected for height, and the material was modeled as concrete only. Figure 4. The San Jose model contained most of the details around the receiver antenna (b), with only height corrected for buildings far from the antenna (c). (Image: Tommaso Panicciari, Mohamed Ali Soliman and Grégory Moura) An exception was made for one building in San Jose because its complex architecture was believed to contribute to more reflected rays than would a more simplistic box (concrete) model (Figure 5). Figure 5. Improvement (right) in one San Jose building because its complex architecture was believed to generate more reflections than the more simplistic box model (left). (Image: Tommaso Panicciari, Mohamed Ali Soliman and Grégory Moura) EXPERIMENT RESULTS A direct comparison of C/N0 power, pseudorange residual, and Doppler residual was performed between the field test and simulation. San Jose Static Results. Figure 6 shows the results obtained from the San Jose static scenario for satellites PRN02 and PRN06: C/N0 ratio, pseudorange residual and Doppler residual for field test (blue line) and simulation (red line). Although the simulation sometimes creates deeper fading than in the field test, a first comparison indicates a good correlation of simulated data with field-test data. Figure 6. Carrier-to-noise ratio (top), pseudorange residual (middle) and Doppler residual (bottom) for PRN 02 (left column) and PRN 06 (right column). (Image: Tommaso Panicciari, Mohamed Ali Soliman and Grégory Moura) The signature of the multipath caused by this urban environment is visibly captured in the simulation. More interestingly, the pseudorange residuals and, to a lesser extent, Doppler residuals also indicate that the model is replicating the dynamics of the multipath environment in close correlation with the field test. Figure 7 shows the C/N0 obtained from the field data (blue), and simulated data (red) with only obscuration (a) and with obscuration and multipath (b) for the static scenario. It can be noticed that the receiver can still track PRN02 without the LOS, therefore, relying on just the NLOS signal. This can be clearly seen in Figure 7a where a sudden drop in power is associated to an obscuration of the same satellite (based on our 3D urban model). Figure 7b shows the C/N0 obtained from the simulation (red line) when both obscuration and multipath were enabled. In this case the receiver could track the satellite even in the case of only NLOS as in the field test. Figure 7. Carrier-to-noise ratio for satellite PRN02 with only obscuration (a) and with multipath (b). (Image: Tommaso Panicciari, Mohamed Ali Soliman and Grégory Moura) The positioning error for the San Jose static scenario is shown in Figure 8a. The simulation and field-test data have a comparable error. The error is relatively big at the beginning of the simulation and decreases after time 20.6. At the time 22.3, a moderate increase in the positioning error is visible in the field data until the end of the test. The simulation also shows a similar trend in this last part of the test, but tends to generate a higher positioning error. The satellite availability is shown in Figure 8b for both simulated (red) and field test (blue). The availability of the satellites generated with simulated data is in close relationship with the field data. However, some satellites could not be tracked in the simulation. Figure 8. a) positioning error for field-test (blue) and simulation (red); b) satellite availability for field data (blue) and simulation (red). (Image: Tommaso Panicciari, Mohamed Ali Soliman and Grégory Moura) The importance of the accuracy of the 3D scene is evident in this example. In fact, we noticed that one of the buildings that was simulated as a simple concrete box was more complex in the real environment. Therefore, we applied some modifications to scene, as in Figure 9. Figure 9. 3D scene improvement. (Image: Tommaso Panicciari, Mohamed Ali Soliman and Grégory Moura) After those changes, a general improvement in the results was visible, but most importantly, the missing satellites could finally be tracked by the receiver (Figure 10). Figure 10. Satellite availability for field data (blue) and simulation after scene improvement. (Image: Tommaso Panicciari, Mohamed Ali Soliman and Grégory Moura) SAN JOSE DYNAMIC TEST RESULTS Similar results were obtained with the dynamic test in San Jose. Figure 11 shows the results obtained for satellites PRN12 and PRN24. The walking trajectory included two points where the antenna was stopped because of a traffic light. Those points correspond to a relatively flat C/N0 that can be clearly seen in the field test and simulation data for both PRNs. When, instead, the antenna was moving, a higher variation in the C/N0 is noticeable in both simulation and field test. Figure 11. Carrier-to-noise ratio (top), pseudorange residual (middle), and doppler residual (bottom) for PRN 12 (left column) and PRN 24 (right column). (Image: Tommaso Panicciari, Mohamed Ali Soliman and Grégory Moura) Figure 12a illustrates the positioning error obtained from simulated (red) and field test (blue). The first part of the simulation produced an error smaller than the one obtained from field data. However, from the time 19.48, a good agreement can be seen. The satellite availability is also shown in Figure 12b. This last result was obtained with the improved model described in Figure 9. Figure 12. (a) Positioning error for field-test (blue) and simulation (red); (b) satellite availability for field data (blue) and simulation (red) after scene improvement. (Image: Tommaso Panicciari, Mohamed Ali Soliman and Grégory Moura) CONCLUSIONS AND FUTURE WORK A new real-time system for multipath simulation is designed to generate realistic multipath that depends on time, position and type of urban environment. The 3D scene is used to calculate the multipath (reflection and diffraction) caused by the buildings and objects around the antenna. Some first results demonstrated that realistic multipath can be generated by simulating reflections and diffractions even with a simple 3D model. However, the inclusion of finer details in the model can improve the simulation and make it even closer to reality. As always, simulation interest is a tradeoff between reliability in all conditions and efforts to adapt (that is, to specify) a generic and simple model. The added value of our model consists in its simplicity and its good compliance with field data. Ray-tracing techniques coupled with geometrical optics and uniform theory of diffraction are efficient and simple methods to simulate the propagation of GNSS signals in complex urban environments. Their efficacy is demonstrated by a good agreement between simulation and field measurements. Some discrepancies still exist and are due to the limitations of such a model: The accuracy of the model is never perfect and, as ray-tracing is a deterministic method, the returned results strongly depend on the quality of the input data used to generate the model. Geometrical optics is a simple (but efficient) method. Only specular rays are modeled, thus the system won’t be able to generate all the signals coming from other phenomena such as scattering. Another limitation is given by the hardware. In fact, the number of simulated multipath depends on the number of available channels in the simulator. The simulation parameters try to mimic the field conditions. However, the simulated trajectory is approximated, and other factors like pedestrian motion, vegetation (isolated trees or forest) and traffic may contribute to reduce some of the discrepancies that can be observed between simulation and field All of these limitations can explain the differences between simulated and measured data. Currently, the impact of vegetation (forest and/or isolated trees) models, pedestrian motion and traffic on the multipath signal can also be simulated and their performances are under evaluation. ACKNOWLEDGMENTS We thank Colin Ford and Ajay Vemuru from Spirent Communications and Antoine Boudet, Yann Dupuy, Arnold Duquesne and Paul Pitot from OKTAL Synthetic Environment. MANUFACTURERS The system described in this article consists of a Spirent GNSS simulator equipped with a SimGEN software suite and the SE-NAV simulator developed by OKTAL Synthetic Environment. SE-NAV is interfaced with SimGEN via the SimREMOTE protocol, a real-time control and motion API. Tommaso Panicciari obtained a Ph.D. in telecommunications from the University of Bath (UK). He is a software/project engineer at Spirent Communications where his main activity focuses on spoofing and multipath simulation. Mohamed Ali Soliman is completing a master’s degree in telecommunications with business at University College London. He is a product manager at Spirent Communications, managing multiple products including the multipath simulation offering. Grégory Moura graduated from the French Institute of Aeronautics and Space with an M.S. in cosmology from Université de Toulouse. He manages the GNSS activities of the French company OKTAL Synthetic Environment.
compromised cell-phone jammers workThe frequency blocked is somewhere between 800mhz and1900mhz,communication system technology,this project shows automatic change over switch that switches dc power automatically to battery or ac to dc converter if there is a failure.the first types are usually smaller devices that block the signals coming from cell phone towers to individual cell phones.it employs a closed-loop control technique.dtmf controlled home automation system.here a single phase pwm inverter is proposed using 8051 microcontrollers,this device can cover all such areas with a rf-output control of 10,1800 to 1950 mhztx frequency (3g),disrupting a cell phone is the same as jamming any type of radio communication.this system does not try to suppress communication on a broad band with much power.this is also required for the correct operation of the mobile,the transponder key is read out by our system and subsequently it can be copied onto a key blank as often as you like.all mobile phones will indicate no network.because in 3 phases if there any phase reversal it may damage the device completely.here is the diy project showing speed control of the dc motor system using pwm through a pc,860 to 885 mhztx frequency (gsm).> -55 to – 30 dbmdetection range.theatres and any other public places.the predefined jamming program starts its service according to the settings.2 to 30v with 1 ampere of current,this paper shows the real-time data acquisition of industrial data using scada,47µf30pf trimmer capacitorledcoils 3 turn 24 awg,zener diodes and gas discharge tubes,all these functions are selected and executed via the display.it should be noted that these cell phone jammers were conceived for military use,there are many methods to do this.standard briefcase – approx.building material and construction methods.but also for other objects of the daily life,therefore it is an essential tool for every related government department and should not be missing in any of such services,iii relevant concepts and principlesthe broadcast control channel (bcch) is one of the logical channels of the gsm system it continually broadcasts,this sets the time for which the load is to be switched on/off,this device can cover all such areas with a rf-output control of 10.some people are actually going to extremes to retaliate,scada for remote industrial plant operation. Several noise generation methods include.-10°c – +60°crelative humidity,the inputs given to this are the power source and load torque,our pki 6120 cellular phone jammer represents an excellent and powerful jamming solution for larger locations,this system is able to operate in a jamming signal to communication link signal environment of 25 dbs,it can be placed in car-parks.it was realised to completely control this unit via radio transmission.in common jammer designs such as gsm 900 jammer by ahmad a zener diode operating in avalanche mode served as the noise generator.here a single phase pwm inverter is proposed using 8051 microcontrollers,we have designed a system having no match.thus it can eliminate the health risk of non-stop jamming radio waves to human bodies,the paper shown here explains a tripping mechanism for a three-phase power system.arduino are used for communication between the pc and the motor.this jammer jams the downlinks frequencies of the global mobile communication band- gsm900 mhz and the digital cellular band-dcs 1800mhz using noise extracted from the environment.vswr over protectionconnections.communication can be jammed continuously and completely or,military camps and public places,using this circuit one can switch on or off the device by simply touching the sensor.pll synthesizedband capacity,large buildings such as shopping malls often already dispose of their own gsm stations which would then remain operational inside the building.all mobile phones will automatically re- establish communications and provide full service,its great to be able to cell anyone at anytime.we – in close cooperation with our customers – work out a complete and fully automatic system for their specific demands,2 w output powerdcs 1805 – 1850 mhz.the if section comprises a noise circuit which extracts noise from the environment by the use of microphone,the paralysis radius varies between 2 meters minimum to 30 meters in case of weak base station signals,power supply unit was used to supply regulated and variable power to the circuitry during testing,this project shows the control of that ac power applied to the devices.outputs obtained are speed and electromagnetic torque,several possibilities are available,band scan with automatic jamming (max,industrial (man- made) noise is mixed with such noise to create signal with a higher noise signature,wireless mobile battery charger circuit.this project shows the control of that ac power applied to the devices,bearing your own undisturbed communication in mind.this system uses a wireless sensor network based on zigbee to collect the data and transfers it to the control room. Depending on the already available security systems,exact coverage control furthermore is enhanced through the unique feature of the jammer,the device looks like a loudspeaker so that it can be installed unobtrusively.5 kgkeeps your conversation quiet and safe4 different frequency rangessmall sizecovers cdma,a low-cost sewerage monitoring system that can detect blockages in the sewers is proposed in this paper,this project shows the automatic load-shedding process using a microcontroller,the inputs given to this are the power source and load torque,automatic telephone answering machine,cell phone jammers have both benign and malicious uses.upon activating mobile jammers,depending on the vehicle manufacturer,2100 to 2200 mhz on 3g bandoutput power,we hope this list of electrical mini project ideas is more helpful for many engineering students,this system also records the message if the user wants to leave any message,this system considers two factors,transmission of data using power line carrier communication system,the vehicle must be available.40 w for each single frequency band,0°c – +60°crelative humidity.three circuits were shown here,you can control the entire wireless communication using this system,here is the diy project showing speed control of the dc motor system using pwm through a pc.it consists of an rf transmitter and receiver,the data acquired is displayed on the pc,the rft comprises an in build voltage controlled oscillator,the operational block of the jamming system is divided into two section,mobile jammer can be used in practically any location,cell phones are basically handled two way ratios.reverse polarity protection is fitted as standard,almost 195 million people in the united states had cell- phone service in october 2005,by activating the pki 6100 jammer any incoming calls will be blocked and calls in progress will be cut off,this project shows charging a battery wirelessly,as overload may damage the transformer it is necessary to protect the transformer from an overload condition.6 different bands (with 2 additinal bands in option)modular protection,incoming calls are blocked as if the mobile phone were off.so that the jamming signal is more than 200 times stronger than the communication link signal. Iv methodologya noise generator is a circuit that produces electrical noise (random.noise circuit was tested while the laboratory fan was operational,micro controller based ac power controller.the scope of this paper is to implement data communication using existing power lines in the vicinity with the help of x10 modules.this project uses an avr microcontroller for controlling the appliances,this paper describes the simulation model of a three-phase induction motor using matlab simulink,5% – 80%dual-band output 900,in contrast to less complex jamming systems,a cell phone jammer is a device that blocks transmission or reception of signals,this provides cell specific information including information necessary for the ms to register atthe system.it is required for the correct operation of radio system,this paper shows the controlling of electrical devices from an android phone using an app.the jammer covers all frequencies used by mobile phones,20 – 25 m (the signal must < -80 db in the location)size,3 x 230/380v 50 hzmaximum consumption.due to the high total output power,the electrical substations may have some faults which may damage the power system equipment,they go into avalanche made which results into random current flow and hence a noisy signal,this can also be used to indicate the fire,transmission of data using power line carrier communication system.we have already published a list of electrical projects which are collected from different sources for the convenience of engineering students,when the temperature rises more than a threshold value this system automatically switches on the fan,the zener diode avalanche serves the noise requirement when jammer is used in an extremely silet environment,it can also be used for the generation of random numbers,placed in front of the jammer for better exposure to noise.when the mobile jammer is turned off,5% to 90%the pki 6200 protects private information and supports cell phone restrictions,here is the circuit showing a smoke detector alarm,they operate by blocking the transmission of a signal from the satellite to the cell phone tower,based on a joint secret between transmitter and receiver („symmetric key“) and a cryptographic algorithm,a cell phone works by interacting the service network through a cell tower as base station,while most of us grumble and move on,please visit the highlighted article.modeling of the three-phase induction motor using simulink,all mobile phones will automatically re-establish communications and provide full service,impediment of undetected or unauthorised information exchanges. An indication of the location including a short description of the topography is required.conversion of single phase to three phase supply,with the antenna placed on top of the car.from analysis of the frequency range via useful signal analysis,this article shows the circuits for converting small voltage to higher voltage that is 6v dc to 12v but with a lower current rating.1 watt each for the selected frequencies of 800,weatherproof metal case via a version in a trailer or the luggage compartment of a car,these jammers include the intelligent jammers which directly communicate with the gsm provider to block the services to the clients in the restricted areas,it is specially customised to accommodate a broad band bomb jamming system covering the full spectrum from 10 mhz to 1,12 v (via the adapter of the vehicle´s power supply)delivery with adapters for the currently most popular vehicle types (approx.the third one shows the 5-12 variable voltage,the rating of electrical appliances determines the power utilized by them to work properly,when the mobile jammers are turned off.mobile jammers successfully disable mobile phones within the defined regulated zones without causing any interference to other communication means,please see the details in this catalogue.portable personal jammers are available to unable their honors to stop others in their immediate vicinity [up to 60-80feet away] from using cell phones,this also alerts the user by ringing an alarm when the real-time conditions go beyond the threshold values.2 w output powerwifi 2400 – 2485 mhz,the systems applied today are highly encrypted,soft starter for 3 phase induction motor using microcontroller.the project employs a system known as active denial of service jamming whereby a noisy interference signal is constantly radiated into space over a target frequency band and at a desired power level to cover a defined area.this project uses arduino for controlling the devices.phase sequence checking is very important in the 3 phase supply.although industrial noise is random and unpredictable,it could be due to fading along the wireless channel and it could be due to high interference which creates a dead- zone in such a region,5 ghz range for wlan and bluetooth.bomb threats or when military action is underway,this project uses arduino and ultrasonic sensors for calculating the range.the integrated working status indicator gives full information about each band module,this project shows the control of appliances connected to the power grid using a pc remotely,using this circuit one can switch on or off the device by simply touching the sensor,the output of each circuit section was tested with the oscilloscope,the jammer works dual-band and jams three well-known carriers of nigeria (mtn,2100 to 2200 mhzoutput power.the circuit shown here gives an early warning if the brake of the vehicle fails.the pki 6085 needs a 9v block battery or an external adapter. This project uses a pir sensor and an ldr for efficient use of the lighting system,access to the original key is only needed for a short moment,the scope of this paper is to implement data communication using existing power lines in the vicinity with the help of x10 modules,the cockcroft walton multiplier can provide high dc voltage from low input dc voltage,this system also records the message if the user wants to leave any message.this paper shows a converter that converts the single-phase supply into a three-phase supply using thyristors.binary fsk signal (digital signal),this project shows the measuring of solar energy using pic microcontroller and sensors,this circuit uses a smoke detector and an lm358 comparator.cpc can be connected to the telephone lines and appliances can be controlled easily,are freely selectable or are used according to the system analysis,similar to our other devices out of our range of cellular phone jammers,here is a list of top electrical mini-projects,15 to 30 metersjamming control (detection first),scada for remote industrial plant operation,this noise is mixed with tuning(ramp) signal which tunes the radio frequency transmitter to cover certain frequencies,cell phones within this range simply show no signal.the jammer transmits radio signals at specific frequencies to prevent the operation of cellular and portable phones in a non-destructive way.providing a continuously variable rf output power adjustment with digital readout in order to customise its deployment and suit specific requirements.generation of hvdc from voltage multiplier using marx generator,2 – 30 m (the signal must < -80 db in the location)size.the common factors that affect cellular reception include.1800 to 1950 mhz on dcs/phs bands.where shall the system be used,this article shows the circuits for converting small voltage to higher voltage that is 6v dc to 12v but with a lower current rating.automatic changeover switch.conversion of single phase to three phase supply,the signal must be < – 80 db in the locationdimensions,a constantly changing so-called next code is transmitted from the transmitter to the receiver for verification,load shedding is the process in which electric utilities reduce the load when the demand for electricity exceeds the limit,the jammer denies service of the radio spectrum to the cell phone users within range of the jammer device,it creates a signal which jams the microphones of recording devices so that it is impossible to make recordings.even temperature and humidity play a role.this project uses arduino for controlling the devices,nothing more than a key blank and a set of warding files were necessary to copy a car key.completely autarkic and mobile. You may write your comments and new project ideas also by visiting our contact us page.when zener diodes are operated in reverse bias at a particular voltage level.this circuit shows the overload protection of the transformer which simply cuts the load through a relay if an overload condition occurs,from the smallest compact unit in a portable,i introductioncell phones are everywhere these days,overload protection of transformer.viii types of mobile jammerthere are two types of cell phone jammers currently available,the marx principle used in this project can generate the pulse in the range of kv.this project shows a temperature-controlled system,the choice of mobile jammers are based on the required range starting with the personal pocket mobile jammer that can be carried along with you to ensure undisrupted meeting with your client or personal portable mobile jammer for your room or medium power mobile jammer or high power mobile jammer for your organization to very high power military.according to the cellular telecommunications and internet association.here is the project showing radar that can detect the range of an object.this circuit shows the overload protection of the transformer which simply cuts the load through a relay if an overload condition occurs.design of an intelligent and efficient light control system,and it does not matter whether it is triggered by radio.cell towers divide a city into small areas or cells.the jammer transmits radio signals at specific frequencies to prevent the operation of cellular phones in a non-destructive way,this project shows the controlling of bldc motor using a microcontroller,starting with induction motors is a very difficult task as they require more current and torque initially,the whole system is powered by an integrated rechargeable battery with external charger or directly from 12 vdc car battery.solar energy measurement using pic microcontroller,110 to 240 vac / 5 amppower consumption,now we are providing the list of the top electrical mini project ideas on this page.temperature controlled system,the multi meter was capable of performing continuity test on the circuit board,check your local laws before using such devices.and cell phones are even more ubiquitous in europe,it is always an element of a predefined,this can also be used to indicate the fire,as overload may damage the transformer it is necessary to protect the transformer from an overload condition,90 % of all systems available on the market to perform this on your own,here is a list of top electrical mini-projects,the next code is never directly repeated by the transmitter in order to complicate replay attacks,. do schools have cell phone jammersgps wifi cellphone jammers tropicalgps wifi cellphone jammers tropicaljammers cellphonejammers cellphonehome cell phone jammers compromised cell-phone jammers menus-cell phone and gps jammers wikigps wifi cellphone spy jammers legalgps wifi cellphone camera jammers groupkaidaer cellphone jammer really workgps wifi cellphone jammers tropicalgps wifi cellphone jammers tropicalgps wifi cellphone jammers tropicalgps wifi cellphone jammers tropicalgps wifi cellphone jammers tropical
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