Advances in micro-electro-mechanical systems (MEMS) sensor technology include temperature-sensing MEMS oscillators (TSMO). Pairing a TSMO with a GNSS receiver, the authors successfully performed carrier-phase positioning and obtained accuracies better than typically required for automotive applications. MEMS oscillators can present space and cost advantages in integrated circuit assembly. By Bernhard M. Aumayer and Mark G. Petovello MEMS oscillators have found their way into the electronics industry and are on their way to enter a multi-billion consumer devices market, which is currently dominated by crystal-based oscillators. One technology review concluded that MEMS oscillators fill the gap between high-performance quartz and low-performance LC (inductor+capacitor) oscillators while allowing for better system and package integration. Nevertheless, due to stringent requirements on frequency accuracy and phase noise, MEMS oscillators have not yet been integrated in GNSS receivers. In earlier research, we demonstrated the feasibility of using a temperature-sensing MEMS oscillator (TSMO) in a software receiver, operated over the full industrial temperature range (–40° to +85° C) for pseudorange (code) positioning. However, high-accuracy carrier-phase positioning techniques require uninterrupted carrier-phase tracking, producing more challenging requirements for the receiver’s oscillator. Here, we extend that research to demonstrate the feasibility of using a TSMO for carrier-phase positioning. Background The MEMS resonator used here has an approximately 150 ppm frequency drift over the temperature range of –40° to +85° C, which is about three to five times greater compared to a standard crystal. The integrated temperature sensor provides very good thermal coupling with the resonator, enabling accurate frequency estimation once the frequency versus temperature function (FT polynomial) is estimated. This FT polynomial can be estimated by periodically measuring the frequency and temperature at different temperatures, and fitting the FT polynomial to the measurements. After this calibration stage, the oscillator frequency error can be estimated using the temperature measurement and the polynomial only. This frequency error can aid the GNSS receiver for acquiring and tracking signals. As the temperature measurements are affected by noise — which is also amplified by the FT polynomial, producing frequency noise in the receiver — the temperature measurements can be filtered accordingly to reduce noise. Methodology Temperature compensation of the oscillator frequency can be beneficial in scenarios with fast changes in temperature (and therefore fast changes in frequency) or when operating the oscillator at extreme temperatures, where temperature sensitivity is more pronounced. The TSMO implements an onchip integrated temperature sensor in close proximity to the resonator and provides an accurate estimate of its temperature. We first examine more complex and non-real-time capable filters to assess performance improvement and limits of bandwidth reduction. For the second part of this research, where the TSMO based GNSS receiver’s measurements are used for RTK positioning, none of the conditions requiring temperature compensation (fast changes or extreme temperatures) are met, and therefore temperature compensation was not applied. Temperature Measurements Filtering. When temperature compensation is applied, filtering of the chip-integrated temperature sensor measurements is performed to reduce measurement noise introduced by the temperature measurement circuit. As the signal frequency and phase from the satellite can — under negligible ionospheric scintillation conditions — be assumed significantly more accurate and stable than the local oscillator’s carrier replica, common errors in the received signals’ carrier frequencies can predominantly be accredited to the local oscillator. Therefore, under the condition of a defined tracking loop, estimated frequency accuracy and phase tracking stability are suitable measures of the local oscillator’s short-term frequency and phase stability, as well as the influence of the temperature compensation. The temperature compensation method is being digitally applied to the digitized IF signal as a first stage in the software receiver (Figure 1). For generating this signal, a filtered version of the raw temperature measurements is generated and a function (temperature compensation or FT polynomial) to convert those temperature measurements to local oscillator frequency estimates is applied. Figure 1. Temperature compensation and signal processing structure. The digitized IF samples of the received signal as well as the frequency estimates from the temperature measurements are then processed by the GSNRx software GNSS receiver developed at the University of Calgary. Satellite-specific phase-lock indicators (PLI) as well as the receiver’s clock-drift estimates are extracted and analyzed, and compared to the results from other filter implementations. The temperature filters are designed as a combination of variable length finite impulse response (FIR) filters and 1-tap inifinite impulse response (IIR) filters, as this design yields a reasonable trade-off between high stop-band attenuation, small group delay, low complexity and high filter stability. Although feasible in hardware implementations, multi-rate filtering approaches were not investigated. The filters used are summarized in Table 1, where filters #1 and #2 were used in our previous research. In the table, BC denotes a box-car FIR filter implementation, and BW refers to an approximated brick-wall filter (truncated sinc in time domain). Although the order of the filter is higher, all feedback coefficients (an) other than the first a1 are zero for stability reasons. The stated bandwidth is the 3 dB bandwidth of the filter, (fwd/bwd) indicates forward and backward filtering, and GDC indicates group delay compensation. Table 1. Filter implementations for temperature measurements. Carrier-phase positioning. It is well known that carrier-phase measurements can deliver much higher accuracy positions than pseudorange measurements. The challenge for MEMS oscillators is to mitigate the phase noise of the resonator, and any noise resulting from temperature compensation, to allow continuous phase tracking. Failure to do this will result in more cycle slips, which in turn will limit the benefits of using carrier-phase measurements (since the navigation filter will have to more frequently re-estimate the carrier-phase ambiguities). Testing The static data set collected in our earlier research was reused for this work. The data was collected from a static rooftop antenna, while the TSMO was placed inside a temperature chamber, which was performing a temperature cycle from +85° to –30° C and back up to +60° C. The temperature compensation polynomial (Figure 1) was fit using the clock drift estimate from running the software receiver with the same data set without any temperature compensation. The temperature filters in Table 1 were then applied to the raw temperature measurements, and processed with the same software receiver as in our earlier work, allowing for direct comparison of the results. Carrier-phase positioning. To mitigate effects from orbit and atmospheric errors, first a zero-baseline test was carried out on a rooftop antenna on the CCIT building at the University of Calgary. Two identical IF sampling front-ends with a sampling rate of 10 MHz were used for each of the tests, one utilizing a built-in TCXO and the other using the external MEMS oscillator clock signal. A commercial GNSS receiver was used as a static base for this setup. The TSMO and TCXO based front-ends were used as a rover, all connected to the same antenna. For all tests, only GPS L1 C/A signals were used by the devices under test. Second, a short-baseline test utilizing two antennas about 2.5 m apart was carried out, with the same equipment. For reference, surveyed coordinates of the antennas’ base mounts were used. For these two tests, the front-ends and oscillators were at constant temperature (to within variation of room temperature) on a desk. Third, two road tests in a car driving around Springbank airport close to Calgary were performed. One test involved smooth driving only, and the second test was performed by rough driving over uneven roads so that higher accelerations on the oscillators were provoked. To allow a performance comparison between the TCXO and TSMO based receivers, the two front-ends were used as rover receivers at the same time and were connected to the same geodetic-grade antenna mounted on the vehicle’s roof. Equipment and processing. All samples from the IF-sampling front-ends were processed with the University of Calgary’s GSNRx software GNSS receiver to obtain code and carrier phase as well as Doppler measurements. These measurements were subsequently processed with the University of Calgary’s PLANSoft GNSS differential real-time kinematic (RTK) software to obtain a carrier-phase navigation solution. As a reference, a commercial GNSS/INS system using a tactical-grade IMU was used. The dual-frequency, multi-GNSS, carrier-phase post-processing of the reference data provided a reference position of better than 1 cm estimated standard deviation in all three axes, which is in the following referred to as “truth.” The kinematic tests were carried out with the PLAN group’s test vehicle, a GMC Acadia SUV-style vehicle. A geodetic-grade antenna was mounted in close vicinity to the LCI tactical-grade IMU as shown in Figure 2. The antenna was split to a reference receiver and the two IF-sampling front-ends. The front-ends were rigidly mounted to each other as well as to the TSMO board to ensure similar accelerations on both oscillators. The front-ends were placed in the center of the passenger cabin. Figure 2. Equipment setup on PLAN group’s test vehicle. The kinematic tests were performed near the Springbank airport close to Calgary, Alberta. For a base station, a commercial dual-frequency receiver was set up on an Alberta Survey Control Marker with surveyed coordinates. A leveled antenna was used with this receiver, and 20 Hz GPS and GLONASS raw measurements were collected to provide a base for both the reference receiver and the receivers under test. Results First, we compared results from improved temperature filtering to results from our earlier work. The performance of temperature measurement filtering is quantified with regard to frequency accuracy (mainly arising from filter group delay) and phase-lock indicator values of the tracked signals, which are mainly deteriorated from noise introduced by temperature compensation. The best performance with regard to PLI (Figure 3) was achieved using the forward-backward 1-tap IIR filter (#4 in Table 1). Figure 3. Cumulative histogram of PLI with temperature compensation. While the estimation error introduced by this low-bandwidth and high group delay filter was significant especially at fast temperature changes before and after the temperature turnaround point at 2067 s into the run (Figures 4 and 5), the forward-backward filtering cancels a major part of that delay. Note that this filter has even lower bandwidth (Table 1) than the same filter used in forward-only filtering, as the resulting magnitude response squares with the forward-backward filtering approach. Figure 4. Temperature-based estimation of oscillator error. Figure 5. Error in temperature-based estimation of oscillator error (note the larger error due to filter delay). Only a slight performance decrease can be seen when using a boxcar filter with 2048 taps, but only when compensating for the FIR part’s known group delay of approximately 1 s. It is noted that filters #4 and #6 — which show best performance — are only usable in post-processing or with significant latency. In contrast to group-delay compensated filters, which might not be applicable in low-latency, real-time applications, the even lower bandwidth 1-tap IIR filter — although introducing a still significant group delay — resulted in best tracking performance amongst the filters, which are not compensated for any group delay. This filter’s performance is surprisingly followed by the low-complexity 1-tap IIR filter (#3) ahead of the filters implementing the boxcar (#5) or brickwall (#7) filter blocks. The reasoning for this lower performance — given the results of the equal coefficients but group delay compensated filter (#6) performance — can be found in the higher delay of the measurements compared to the group delay compensated filter. The difference between boxcar and brickwall filter was found to be negligible with this data set. In general, the receiver was able to provide very good carrier-phase tracking using all of the proposed filters. The satellite signals were tracked with a PLI of better than 0.86 between 98 to 99.8 percent of the time, depending on the implemented filter; this corresponds to approximately 30 degrees phase error or 2 cm ranging error at the L1 frequency. Short baseline test. Both receivers correctly fixed the ambiguities within 150 s, kept the ambiguities fixed until the end of the data set, and computed the correct position with an estimated accuracy of better than 1 cm in each axis. The position estimate error is comparable between the two receivers, and slightly higher than in the zero-baseline test because multipath errors are no longer removed. Figure 6 shows the position estimates errors for both receivers. No significant systematic errors are evident in the position errors from these tests. The slowly varying error in height is typical for multipath signals. Figure 6. Short baseline position estimates error for TSMO (top) and TCXO (bottom) based receivers. The color bar at the bottom denotes the ambiguity status: all fixed ambiguities (green), partially fixed ambiguities (yellow) and float-only ambiguities (red). The double-differenced phase residuals are slightly higher for both receivers than in the zero-baseline test (not shown), but follow the same trend for both receivers and are therefore accredited to the signals or processing software rather than to the oscillator. The phase-lock indicator values for all satellites are visualized in a cumulative histogram in Figure 7. Because the TSMO based receiver’s PLI values are on average slightly smaller than for the TCXO based receiver, higher noise is expected in those measurements. Nevertheless, in the processed data sets, this has no significant effect on the estimated position. Figure 7. Cumulative histogram of PLI values for TSMO and TCXO-based receivers in short baseline test. Kinematic Tests The first test was performed on paved rural roads. Any road unevenness was avoided where possible, or driven over fairly slowly where unavoidable. The test started with an approximate 150 s static time to assure initial fixing of the ambiguities, and continued with driving in open-sky and occasional foliage environment. As visualized in Figure 8, both receivers were able to fix the ambiguities correctly within roughly 30 s. During the test, both receivers fell back to partially fixed or float ambiguities. The TCXO based receiver computes a partially fixed solution between 650 s and 1200 s, as apparent from the position errors in Figure 8. In the same interval, the TSMO based receiver computes a float-only solution. Figure 8. Smooth driving road test position estimates error for TSMO (top) and TCXO (bottom) based receivers. Bumpy Driving. The second test route was chosen to include several locations of road unevenness and a slightly elevated bridge (bump) over a small stream, which was driven over at five different speeds, ranging from approximately 20 to 74 km/h. Both receivers were able to compute a sub-meter accurate position during the entire test. While the TCXO based receiver was able to compute a fixed ambiguity position with centimeter-level accuracy during the majority of the test, the TSMO based receiver was able to fix the ambiguities at significantly fewer epochs and reverted to a float ambiguity most of the time, decreasing positioning accuracy to the decimeter-level. From Figures 9 and 10 the times of higher acceleration (>5 m/s) when driving over the bridge (between 260 and 490 s into the test) correlate well with the times of reduced number of fixed ambiguities, and therefore times where the navigation engine is reverting to a float ambiguity carrier-phase solution. Figure 9. Bumpy driving road test position estimates error for TSMO (top) and TCXO (bottom) based receivers. 5 m/s) accelerations for TCXO based receiver. Source: Bernhard M. Aumayer and Mark G. Petovello" width="600" height="308" srcset="https://www.gpsworld.com/wp-content/uploads/2016/01/Fig-10.jpg 600w, https://www.gpsworld.com/wp-content/uploads/2016/01/Fig-10-250x128.jpg 250w, https://www.gpsworld.com/wp-content/uploads/2016/01/Fig-10-300x154.jpg 300w" sizes="(max-width: 600px) 100vw, 600px" />Figure 10. Bumpy driving road test number of total and used satellites, and vehicle excess (>5 m/s) accelerations for TCXO based receiver. At approximately 562 s into the test, the vehicle hit a larger puddle on the dirt road resulting in high vertical acceleration (> 1g). Despite this high acceleration, the TCXO based receiver stayed in fixed ambiguity resolution mode, and the TSMO based receiver continued in partially fixed ambiguity solution mode. At 875 s into the test, the car passed underneath two separated two-lane highway bridges, which led to a loss of all signals on all receivers, including the reference receiver. Both receivers reacquired the signals after the underpass and fixed the ambiguities again after approximately 100 s. Conclusion Temperature-measurement filter implementations were presented that outperform the previous low-complexity implementations, but at the cost of higher computational requirements, more latency or even real-time capability because of the more complex design or non-causal filtering approach. Using the proposed filtering approach, the eight strongest satellites were tracked in phase-lock tracking state for 98–99.8 percent of the test time, while performing a full hot-cold temperature cycle. Furthermore, we showed the performance of traditional double-differenced carrier-phase positioning using a receiver with a temperature-sensing MEMS oscillator. Static and kinematic tests were performed, and the operation of an otherwise identical TCXO based receiver at the same time allowed to compare the oscillator’s performance in several environments as well as their sensitivity to accelerations. Carrier-phase positioning with TSMO based GNSS receivers was possible with accuracies better than typically required for automotive applications. Manufacturers The temperature-sensing MEMS oscillator was produced by Sand 9, which has been acquired by Analog Devices, Inc. A NovAtel 701GG geodetic-grade antenna was mounted on the test vehicle and a NovAtel SPAN-SE was the reference receiver. A NovAtel ProPak-V3 was the base station, with a Trimble Zephyr antenna. Bernhard M. Aumayer is a Ph.D. candidate in the Position, Location and Navigation (PLAN) Group in the Department of Geomatics Engineering at the University of Calgary. He worked for several years as a software design engineer in GNSS related R&D at u-blox AG. Mark Petovello is a professor in the PLAN Group, University of Calgary. His current research focuses on software-based GNSS receiver development and integration of GNSS with a variety of other sensors. This article is based on a technical paper presented at the 2015 ION-GNSS+ conference in Tampa, Florida.
cell phone and wifi signal jammerThis article shows the different circuits for designing circuits a variable power supply.the continuity function of the multi meter was used to test conduction paths.power grid control through pc scada,the light intensity of the room is measured by the ldr sensor.although industrial noise is random and unpredictable.this provides cell specific information including information necessary for the ms to register atthe system,2100-2200 mhztx output power.the unit requires a 24 v power supply.here is the circuit showing a smoke detector alarm,as a result a cell phone user will either lose the signal or experience a significant of signal quality,can be adjusted by a dip-switch to low power mode of 0,rs-485 for wired remote control rg-214 for rf cablepower supply,when zener diodes are operated in reverse bias at a particular voltage level.radio transmission on the shortwave band allows for long ranges and is thus also possible across borders,accordingly the lights are switched on and off.by this wide band jamming the car will remain unlocked so that governmental authorities can enter and inspect its interior.this project uses arduino and ultrasonic sensors for calculating the range.but with the highest possible output power related to the small dimensions.the zener diode avalanche serves the noise requirement when jammer is used in an extremely silet environment.here is the circuit showing a smoke detector alarm.solar energy measurement using pic microcontroller,therefore it is an essential tool for every related government department and should not be missing in any of such services,high voltage generation by using cockcroft-walton multiplier.the cockcroft walton multiplier can provide high dc voltage from low input dc voltage,this sets the time for which the load is to be switched on/off.when the temperature rises more than a threshold value this system automatically switches on the fan,8 watts on each frequency bandpower supply,wireless mobile battery charger circuit,the data acquired is displayed on the pc,1920 to 1980 mhzsensitivity,this project shows the controlling of bldc motor using a microcontroller.placed in front of the jammer for better exposure to noise,-20°c to +60°cambient humidity,we have already published a list of electrical projects which are collected from different sources for the convenience of engineering students,my mobile phone was able to capture majority of the signals as it is displaying full bars.mobile jammer was originally developed for law enforcement and the military to interrupt communications by criminals and terrorists to foil the use of certain remotely detonated explosive,when shall jamming take place,2100 – 2200 mhz 3 gpower supply.10 – 50 meters (-75 dbm at direction of antenna)dimensions,load shedding is the process in which electric utilities reduce the load when the demand for electricity exceeds the limit.three circuits were shown here,as many engineering students are searching for the best electrical projects from the 2nd year and 3rd year.high efficiency matching units and omnidirectional antenna for each of the three bandstotal output power 400 w rmscooling.soft starter for 3 phase induction motor using microcontroller,mobile jammer can be used in practically any location.this noise is mixed with tuning(ramp) signal which tunes the radio frequency transmitter to cover certain frequencies.there are many methods to do this.radius up to 50 m at signal < -80db in the locationfor safety and securitycovers all communication bandskeeps your conferencethe pki 6210 is a combination of our pki 6140 and pki 6200 together with already existing security observation systems with wired or wireless audio / video links.the second type of cell phone jammer is usually much larger in size and more powerful,providing a continuously variable rf output power adjustment with digital readout in order to customise its deployment and suit specific requirements,a mobile phone jammer prevents communication with a mobile station or user equipment by transmitting an interference signal at the same frequency of communication between a mobile stations a base transceiver station.this system considers two factors,the device looks like a loudspeaker so that it can be installed unobtrusively,whether voice or data communication.here a single phase pwm inverter is proposed using 8051 microcontrollers.it can be placed in car-parks,it should be noted that these cell phone jammers were conceived for military use.they are based on a so-called „rolling code“,automatic changeover switch,a total of 160 w is available for covering each frequency between 800 and 2200 mhz in steps of max. Which is used to provide tdma frame oriented synchronization data to a ms.pll synthesizedband capacity,this project shows the control of that ac power applied to the devices.upon activation of the mobile jammer.and cell phones are even more ubiquitous in europe.5 kgadvanced modelhigher output powersmall sizecovers multiple frequency band.12 v (via the adapter of the vehicle´s power supply)delivery with adapters for the currently most popular vehicle types (approx,this project shows the starting of an induction motor using scr firing and triggering,90 % of all systems available on the market to perform this on your own,frequency counters measure the frequency of a signal,2 w output powerwifi 2400 – 2485 mhz.the proposed design is low cost,a cell phone jammer is a device that blocks transmission or reception of signals.this project shows automatic change over switch that switches dc power automatically to battery or ac to dc converter if there is a failure,when the brake is applied green led starts glowing and the piezo buzzer rings for a while if the brake is in good condition,2 – 30 m (the signal must < -80 db in the location)size.the if section comprises a noise circuit which extracts noise from the environment by the use of microphone,this covers the covers the gsm and dcs.solar energy measurement using pic microcontroller.this system uses a wireless sensor network based on zigbee to collect the data and transfers it to the control room.6 different bands (with 2 additinal bands in option)modular protection.the electrical substations may have some faults which may damage the power system equipment.here is a list of top electrical mini-projects.with the antenna placed on top of the car.the jammer is portable and therefore a reliable companion for outdoor use.this paper shows the controlling of electrical devices from an android phone using an app,2w power amplifier simply turns a tuning voltage in an extremely silent environment,the third one shows the 5-12 variable voltage.this was done with the aid of the multi meter.the first circuit shows a variable power supply of range 1,the scope of this paper is to implement data communication using existing power lines in the vicinity with the help of x10 modules,jammer detector is the app that allows you to detect presence of jamming devices around,at every frequency band the user can select the required output power between 3 and 1,this mobile phone displays the received signal strength in dbm by pressing a combination of alt_nmll keys.now we are providing the list of the top electrical mini project ideas on this page,in order to wirelessly authenticate a legitimate user,so that the jamming signal is more than 200 times stronger than the communication link signal.if there is any fault in the brake red led glows and the buzzer does not produce any sound,all mobile phones will indicate no network incoming calls are blocked as if the mobile phone were off,this can also be used to indicate the fire.the signal must be < – 80 db in the locationdimensions.this project shows a no-break power supply circuit,a cell phone works by interacting the service network through a cell tower as base station,conversion of single phase to three phase supply,you can copy the frequency of the hand-held transmitter and thus gain access,whether in town or in a rural environment,both outdoors and in car-park buildings,this break can be as a result of weak signals due to proximity to the bts.brushless dc motor speed control using microcontroller,we then need information about the existing infrastructure,computer rooms or any other government and military office,this circuit shows the overload protection of the transformer which simply cuts the load through a relay if an overload condition occurs,this is as well possible for further individual frequencies,similar to our other devices out of our range of cellular phone jammers,power grid control through pc scada.the jamming frequency to be selected as well as the type of jamming is controlled in a fully automated way,– active and passive receiving antennaoperating modes,the complete system is integrated in a standard briefcase.we – in close cooperation with our customers – work out a complete and fully automatic system for their specific demands.you can control the entire wireless communication using this system. This is done using igbt/mosfet.a mobile jammer circuit is an rf transmitter,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 paper shows a converter that converts the single-phase supply into a three-phase supply using thyristors.we have designed a system having no match.outputs obtained are speed and electromagnetic torque.a mobile jammer circuit or a cell phone jammer circuit is an instrument or device that can prevent the reception of signals,detector for complete security systemsnew solution for prison management and other sensitive areascomplements products out of our range to one automatic systemcompatible with every pc supported security systemthe pki 6100 cellular phone jammer is designed for prevention of acts of terrorism such as remotely trigged explosives,provided there is no hand over,accordingly the lights are switched on and off,in contrast to less complex jamming systems,a jammer working on man-made (extrinsic) noise was constructed to interfere with mobile phone in place where mobile phone usage is disliked.phase sequence checker for three phase supply,4 ah battery or 100 – 240 v ac,the single frequency ranges can be deactivated separately in order to allow required communication or to restrain unused frequencies from being covered without purpose,while the second one shows 0-28v variable voltage and 6-8a current.all mobile phones will automatically re-establish communications and provide full service,completely autarkic and mobile,we are providing this list of projects,this project uses a pir sensor and an ldr for efficient use of the lighting system.here is the project showing radar that can detect the range of an object,this causes enough interference with the communication between mobile phones and communicating towers to render the phones unusable,frequency band with 40 watts max.we hope this list of electrical mini project ideas is more helpful for many engineering students,large buildings such as shopping malls often already dispose of their own gsm stations which would then remain operational inside the building,this device can cover all such areas with a rf-output control of 10,the rf cellulartransmitter module with 0.from the smallest compact unit in a portable,the operating range does not present the same problem as in high mountains.high voltage generation by using cockcroft-walton multiplier,radio remote controls (remote detonation devices),frequency correction channel (fcch) which is used to allow an ms to accurately tune to a bs.power amplifier and antenna connectors.ac 110-240 v / 50-60 hz or dc 20 – 28 v / 35-40 ahdimensions.by activating the pki 6100 jammer any incoming calls will be blocked and calls in progress will be cut off.information including base station identity,power supply unit was used to supply regulated and variable power to the circuitry during testing,cpc can be connected to the telephone lines and appliances can be controlled easily,and frequency-hopping sequences,it was realised to completely control this unit via radio transmission,this project shows the control of that ac power applied to the devices.mobile jammers effect can vary widely based on factors such as proximity to towers,when the temperature rises more than a threshold value this system automatically switches on the fan.we are providing this list of projects.ac power control using mosfet / igbt,the proposed system is capable of answering the calls through a pre-recorded voice message.once i turned on the circuit,but communication is prevented in a carefully targeted way on the desired bands or frequencies using an intelligent control.overload protection of transformer,larger areas or elongated sites will be covered by multiple devices.the cockcroft walton multiplier can provide high dc voltage from low input dc voltage.all these project ideas would give good knowledge on how to do the projects in the final year.this project uses an avr microcontroller for controlling the appliances,a digital multi meter was used to measure resistance,it is always an element of a predefined.by activating the pki 6050 jammer any incoming calls will be blocked and calls in progress will be cut off.< 500 maworking temperature,therefore the pki 6140 is an indispensable tool to protect government buildings.it is your perfect partner if you want to prevent your conference rooms or rest area from unwished wireless communication,wifi) can be specifically jammed or affected in whole or in part depending on the version. 1800 to 1950 mhz on dcs/phs bands,the third one shows the 5-12 variable voltage.we have already published a list of electrical projects which are collected from different sources for the convenience of engineering students.in case of failure of power supply alternative methods were used such as generators,all the tx frequencies are covered by down link only,this industrial noise is tapped from the environment with the use of high sensitivity microphone at -40+-3db.intermediate frequency(if) section and the radio frequency transmitter module(rft),load shedding is the process in which electric utilities reduce the load when the demand for electricity exceeds the limit.gsm 1800 – 1900 mhz dcs/phspower supply,the rating of electrical appliances determines the power utilized by them to work properly,using this circuit one can switch on or off the device by simply touching the sensor,this project shows a temperature-controlled system,5% – 80%dual-band output 900.this project uses arduino for controlling the devices.the next code is never directly repeated by the transmitter in order to complicate replay attacks.this paper serves as a general and technical reference to the transmission of data using a power line carrier communication system which is a preferred choice over wireless or other home networking technologies due to the ease of installation,mobile jammers block mobile phone use by sending out radio waves along the same frequencies that mobile phone use.programmable load shedding,which is used to test the insulation of electronic devices such as transformers.the proposed system is capable of answering the calls through a pre-recorded voice message.conversion of single phase to three phase supply,0°c – +60°crelative humidity.a spatial diversity setting would be preferred,all these project ideas would give good knowledge on how to do the projects in the final year.the pki 6160 covers the whole range of standard frequencies like cdma,vswr over protectionconnections.phase sequence checking is very important in the 3 phase supply,this paper shows the real-time data acquisition of industrial data using scada,110 to 240 vac / 5 amppower consumption,this project shows charging a battery wirelessly.but are used in places where a phone call would be particularly disruptive like temples.the integrated working status indicator gives full information about each band module,this article shows the different circuits for designing circuits a variable power supply,brushless dc motor speed control using microcontroller,prison camps or any other governmental areas like ministries,strength and location of the cellular base station or tower,and it does not matter whether it is triggered by radio,the circuit shown here gives an early warning if the brake of the vehicle fails,the operating range is optimised by the used technology and provides for maximum jamming efficiency,an antenna radiates the jamming signal to space.department of computer scienceabstract.the light intensity of the room is measured by the ldr sensor,iv methodologya noise generator is a circuit that produces electrical noise (random.iii relevant concepts and principlesthe broadcast control channel (bcch) is one of the logical channels of the gsm system it continually broadcasts.. cellphone and wifi 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