Category Archives: Electronic Gadgets for the Evil Genius BOB IANNINI

Ultrasonic Microphone

This interesting electronic project enables you to clearly hear a world of sounds beyond that of human ability. The possible applications of the ultrasonic microphone you will create (see Figure 26-1) range from the detection of leaking gases, liquids, the mechanical wear of bearings, rotational and recipro­cating devices, and electrical leakage on power-line insulators. A whole world of sounds coming from liv­ing creatures is also audible. Simple events like a cat walking across wet grass, the rattling of key chains, and even a collapsing plastic bag all are clearly heard. On a warm summer night, the sounds that can be heard are remarkable, as bats to small insects all perform a cacophony of nature’s own orchestra at its best.

Ultrasonic Microphone

Figure 26-1 Ultrasonic microphone with parabolic reflector

This handheld and directional microphone easily dclecls and locates these high-frequency sounds. The addition of a parabolic reflector further enhances the performance of this project. Expect to spend $30 lo $50 for this rewarding effort.

This project enables you to listen to a world of sound that few people even know exists. The unit is built in a gun configuration with the barrel housing the elec­tronics. A rear panel contains the on/off volume, the tuning control pot. and the headphone jack. The front of the unit contains the directional receiving trans­ducer. The handle houses the batteries.

The addition of an optional parabolic reflector greatly enhances the device’s performance, providing super-high gain and directivity.

Rpplications

One of the most interesting sources of high-fre – quency sound is the many species of insects emitting their mating and warning calls. On a typical summer night, one can spend hours listening to bats and other strange insect noises. A whole new world of natural sound awaits the user. Many man-made sounds also generate high-frequency sounds easily detected by the devicc. Several examples are as follows, yet these only represent a small fraction of the potential sources of high-frcquency sounds:

• Leaking gases and rushing air.

■ Water from sprinklers or leaks.

• Corona leakage, sparking devices, or lightning.

■ Fires and chemical reactions.

■ Animals walking in wet grass or in the brush can be heard over a considerable distance. This is an excellent aid for hunters or trackers, or for iust finding pets ai night.

■ Computer monitors. TV sets, high-frequency oscillators, mechanical wear bearings, rattle detection often developing in automobiles, plastic bags, and rattling change.

An excellent demonstration of this ultrasonic microphonc would involve Doppler shifts where motion toward the source produces a rise in fre­quency and motion away from it does the opposite.

Doppler shift is when an observer moving toward a source of sound experiences an increasing fre­quency. This is easy to visualize when one realizes that sound propagates as a longitudinal wave at a rel­atively constant velocity. As the observer moves toward the direction of the sound source, he inter­cepts more waves in a shorter period of time, thus hearing a sound that seems to be shorter in wave­length or higher in frequency.

A fun game both for children and adults is to hide a small test oscillator and attempt to have your oppo­nent locate it in a minimal amount of time.

Exploding ULIire Disruption Suuitch (High-Pouuer, High – Frequency Pulse)

This is where the stored energy in the circuit induc­tance is released as an explosion of electromagnetic energy at broadband proportions. The released energy is a function of LI2 where I is the current rise in the spark gap switch at the moment the wire explodes and L is the inductance. The actual power lost in the spark switch is but a fraction of that emit­ted in the explosion of the wire.

Selection of the wire size must take into considera­tion the elcctrical circuit parameters for the proper timing of the optimum release of energy. We experi­mented with a .I-millimeter (.004 inch) to.3-miIlime – ter (.012 inch) diameter of brass and aluminum wire about 50 centimeters in length. The wire is attached by a sandwiching action between two flat brass wash­ers as shown. Note that a longer wire will tend to pro­duce more of a magnetic pulse, whereas a shorter will produce more of an electric pulse.

Charger

The charger for the system can be any current – limited source with an open-circuit voltage in excess of 50 Kv. The charging current rate will determine the amount of time necessary to reach a firing level and need not be that fast for this experimental system. A single charging cycle produces approximately 500 joules per shot and requires reloading of the wire for an exploding disrupter switch. A 2-milIiampere cur­rent source will charge the.5 mfd capacitor to 50 Kv in approximately 5 seconds. This is shown mathemati­cally by t = cv/i(.5)(10e — 6)(5 X 10,000/.002). This rate is more than ample and there is no advantage to a higher-current system unless you are planning to do a multiple discharge system using a spark gap-driven radiator or wire-dispensing scheme.

The ion supply described in Chapter 1 can supply an open-circuit voltage of 50 Kv by easily adding four more capacitors and high-voltage diodes to the multi­plier section. Everything else can remain the same.

Exploding ULIire Disruption Suuitch (High-Pouuer, High - Frequency Pulse)

Rssembly

RFC1 Radio Frequency Choke

This component is necessary to keep the fast current pulse rise isolated from the charger multiplier diodes that could be avalanched by the rapid dv/dt. The sug­gested value is around.2 mh with.3 Uh tertiary coils. The assembly can be a single-layer close wound winding of 150 turns for the.2 mh section. Wind three turns spaced over 1 inch for the.3 Uh section. Use #28 magnet wire on a 1 Ч2- X 12-inch PVC plastic tube.

R1 Resistor

Intended as a safety precaution, this resistor provides a high impedance should a short occur in the output stage of the current driver. Use approximately 50 to 100K with at least 100 watts.

Our lab pulser is shown constructed using materials and parts available from any hardware store. The structure uses a combination of 3/<j-inch schedule 40 PVC tubing for the pillars and flat-faced end caps for the retainers (see Figure 25-4). Partitions are made from nonconductive material of structural integrity for the application. We used 3/s-inch, clear, acrylic plate stock. Figure 25-3 shows the scheme we used to attach these sections to the flat-faced end caps. The sections are secured by drilling clearance holes and plastic tie wraps keep them together. PVC cement is obviously stronger but prevents disassembly unless you destroy the support structure.

The pillar and cap assemblies are attached to the partition plates using 1-inch X */4-20 bolts and nuts. A cradle assembly fabricated from wood or plastic secures the capacitor Cl to the bottom partition. This scheme stabilizes the bottom of the capacitor.

The metal plate sections extend the terminal con­nections of the capacitor. These attach to the termi­nals connecting to the exploding wire cavity section

Exploding ULIire Disruption Suuitch (High-Pouuer, High - Frequency Pulse)

Figure 25-4 Side view of EMP pulser

via brass-threaded rods sleeved into pieces of -’/4-inch made adjustable by adjusting the bottom nut on the

PVC pillar tubing. The bottom spark gap electrode is extended rod.

You will note the four longer pillars are positioned at the corners of the bottom and middle partition plates. The shorter pillars, however, are positioned at the midsections of the middle and top partition plates. This layout is shown in figure 25-5. Figure 25-6 illustrates the final view of the pulser and Figure 25-7 shows the spark switch setup for coupling to the antenna.

Exploding ULIire Disruption Suuitch (High-Pouuer, High - Frequency Pulse)

Exploding ULIire Disruption Suuitch (High-Pouuer, High - Frequency Pulse)

Figure 25-5 Top view of middle partition plate, showing the x-ray view of capacitor placement and mounting holes

Exploding ULIire Disruption Suuitch (High-Pouuer, High - Frequency Pulse)

Event action occurs along the wire that explodes. The foci point of the dish is not exact for all points of the explosion event Expenment for best results

Our low-cost open-air spark switch is shown Serious experimenters may want to consider our triggered enclosed devices as on cover sheet

Charging

resistor

Figure 25-6 Final view of pulser, showing conic antenna

Exploding ULIire Disruption Suuitch (High-Pouuer, High - Frequency Pulse)

Rpplication

This system is intended for research into the suscepti­bility of sensitive electronic equipment to an EMP The system can be scaled down for portable field use and operate on rechargeable batteries. It can be

scaled up to produce kilojoule pulses at the user’s own risk. No attempt to construct or use this device should be considered unless thoroughly experienced in the use of high-pulse energy systems.

The electromagnetic energy pulse can be focused or made parallel by use of a parabolic reflector. Experimental targets can be any sensitive electronic

Exploding ULIire Disruption Suuitch (High-Pouuer, High - Frequency Pulse)

Form coil from 3 turns o! J" ID coppertube 3” diameter Adjust to 3 to 6" length to obtain required inductance

}■’ threaded rod is sleeved into ID of copper tubing and soldered with a propane torch Rod is retained in position by shaft collars

Exploding ULIire Disruption Suuitch (High-Pouuer, High - Frequency Pulse)

Figure 25-7 Spark switch setup and layout for low-frequency coupling to antenna

equipment or even a gas-discharge lamp. Hie acousti­cal spark energy can produce a sonic shockwave of high sound pressure at the focal length of the para­bolic antenna.

Sources

High-voltage chargers, transformers, capacitors, gas – filled and isotope doped spark switches, MARX impulse generators up to 2 megavolts, and EMP gen­erators are all available at www. amazingl. com.

Spark Sujitch

The spark gap switches the energy from the capacitor into the inductor where a resonant tank is momentar­ily set up (see Figure 25-2). The current rise time occurs over the period pi/2 X (LC) ‘.The gap separa­tion distance is set to fire at the desired breakdown voltage. The impedance of the spark switch is deter­mined by the equation ZSP = (к X l)/Q, where к equals.8 X 10 I equals the spark gap distance in centimeters, and Q equals ihe amps per second (coulombs) of discharge. The gap is self-firing and requires no external triggering. The gap assembly is an integral part of the discharge path and must be constructed to minimize inductance and resistance.

Spark Sujitch

before V reaches 50,000 volts. Once fired, a peak current rise cf di/dt=V/L occurs. The period of circuit response is functional of 16 x (LC)S The capacitor now discharges into ihe circuit inductance in 1/4t with the peak current now causing Ihe wire to explode and imerrupting lhis current just before it peaks. The inductive energy (LI2) is released in an explosive burst of broadband electromagnetic radiation. The peak power is derived via the following and rs m excess of many megawatts!’!!!

1. Charging Cycle – dv=ldt/C (Expresses the voitage charging on Ihe capecitor as a f(t) with I constant current)

2. Storage energy in С as a f(v): E=.5Cv2 (Expresses energy in joules as the voltage increases)

3 Response time 1/4 cycle current peak: 1 57(LC) fi (Expresses the time for the first resonant current peaking when ihe spark switch fires)

4. Peak current in 1/4 cycle. V(C/L)S (Expresses the peak current)

5. Initial response as a (1)1. Ldi/dt+iR+1 /С+1 /Cint idt = 0 [Expresses voltages as a f(t)l 6 Energy joules in inductor E= ,5Li2

7. Response when circuit is disrupted at max current through L:

Ld2 i/dt2 + Rdi/dt + it/C = dv/dt. One now sees the explosive effects of the first term of this simpte equation as the energy in the inductor must go somewhere in a very short time, resulting in an explosive E X В field energy release.

An appreciable pulse of many megawatts in the upper RF energy spectrum can be obtained by destabilizing the LCR circuit as shown above. The only limiting factor is the intrinsic real resistance that is always present in several forms, such as leads, skin effect, dielectric and switching losses, etc. These losses must be minimized for optimum resuits. The RF output can be coupled to a parabolic microwave dish or tuned hom. The Q of the output will depend to an extent on the geometry of the wire switch. Longer lengths will produce more "B" field characteristics while short more "E" field. These perameters will enter into the coupling equations regarding the radiation efficiency of the antenna. Experimenting is the besi approach using your math skills only for approximating key parameters Damage to circuitry usuallly is the result of very high di/dt (B field) pulse properties. This is a point of discussion!!

Figure 25-2 EMPpitlser schematic

a threaded rod and locking jam nut scheme. The top ball also uses a threaded rod that fits into the 74-inch PVC tubing used for the structural support of the wire disruption scheme.

The fabrication of our lab test unit is shown and you may deviate with your own ideas, but the objective must be minimal circuit impedance.

You will note that the bottom ball of the spark gap switch is at a high potential and is made adjustable by

Foci вгва ot parabolic алмпла

COMMOWGRD

Retaining blocks to keep bottom of С1 secured

Figure 25-3 Front view of pulser showing spark switch

Low-induclanee extension pieces are used to lengthen the capacitor terminals and are fabricated from ‘/4-inch brass plates with mating holes to the existing block terminals of the capacitor. The edges are rounded and smoothed to prevent corona.

Dimension of spark switch and output section will depend on the maximum value of the charging voltage used

Tungsten/cerium electrodes are recommended The brass spheres provide a frictional press fit as well as some cooling.

Spark Sujitch

Partition plate—’ Nut & bolt

The method we used to attach pillars to partition plates using fist-faced end caps attached with 1/4-20 nuts and bolts Drill holes through cap and pillar for tie wraps to secure together Note there are 24 of these attachment points!

I he open-air, self-triggering spark switch is intended as a low-cost approach to this very strategic part. A system of this type requires the fastest switch­ing times possible. Gas-filled, triggered gaps will switch faster ihan open air. and isotope doped elec­trodes will further enhance performance.

Electromagnetic Pulse (EMP)

Electromagnetic Pulse (EMP)

This advanced project shows how to produce a multi – megawatt pulse of electromagnetic energy that can cause irreversible damage to computerized and sensi­tive communication equipment. A nuclear detonation causes such a pulse, which must be countermeasured lo protect electronic devices. This project requires lethal amounts of electrical energy storage and must not be attempted unless in a qualified laboratory environment. Such a device can be used to deactivate

the computer systems in automobiles, avoiding dan­gerous high-speed chases. Sensitive electronic equip­ment can be tested for susceptibility to lightning and potential nuclear detonations.

The project is semidetailed with references made only to the major components. A low-cost, open-air spark switch is shown but will provide only limited results. A gas-filled or isotope doped switch is required for optimum results (see Figure 25-1).

Basic Description

Shockwave generators are capable of producing focused acoustic or electromagnetic energy that can break up objects such as kidney stones and other sim­ilar materials. Electromagnetic pulse (EMP) genera­tors can produce pulses of electromagnetic energy that can destroy the sensitive electronics in comput­ers and microprocessors. Destabilized inductive and capacitive (LC) circuits can produce multigigawatt pulses by using an explosive wire disruption switch. These high-power pulses can be coupled into parallel plate transmission lines for EMP hardness testing, parabolic and elliptical antennas, horns, and so on for directional far-field effects.

For example, research is currently being under­taken to develop a system that would disable a car during a dangerous high-speed chase. The trick is generating a high enough power pulse to fry the elec­tronic control processor modules. This would be a lot simpler if the vehicle were covered in plastic or fiber­glass rather than metal. The shielding of the metal body offers a challenge to the researcher developing a practical system. A device could be built to do this, but it would be costly and could produce collateral damage to friendly targets.

Project Objective

The objective here is to generate a high-peak power pulse of electromagnetic energy to test the hardness of sensitive electronic equipment. Specifically, this project explores the use of such a device for disabling vehicles by jamming or destroying computerized con­trol chips. We’ll experiment with disruptive LCR cir­cuits with focused Shockwave capabilities.

Hazards

The project uses deadly electrical energy that can kill a person instantly if improperly contacted. The high – energy system that will be assembled uses exploding

wires that can create dangerous shrapnel-like effects. A discharge of the system can severely damage nearby computers and other related equipment.

Theory

A capacitor (C) is charged from a current source to an energy source over a period of time. Once it reaches a certain voltage corresponding to a certain energy level, it is allowed to discharge quickly into a resonant circuit. A wire now is made to explode, dis­rupting this high-peak current through the circuit inductance. A powerful, undampened wave is now generated at the natural frequency and at the associ­ated harmonics of this resonant circuit. The induc­tance (L) of the resonant circuit may consist of a coil and associated lead inductance, along with the intrin­sic inductance of the capacitor, which is around 20 nanohenries. The capacitor of the circuit determines the energy storage and also has an effect on the reso­nant frequency of the system.

Radiation of the energy pulse can be made via a conductive conic section or a metal, horn-like struc­ture. Some experimenters have used lumped, half­wave elements center-fed by a coil coupled to the coil of the resonant circuit. This half-wave antenna con­sists of two quarter-wave sections tuned to the reso­nant circuit frequency. These are in the form of coils wound with an approximate length of wire equal to a q uarter-wavelength. The antenna has two radiation lobes parallel to its length or broadside. Minimum radiation occurs at points axially located or at its ends, but we have not validated this approach. For example, a gas discharge lamp, such as a household fluorescent lamp, will flash brightly at a distance from the source, indicating a powerful directional pulse of electromagnetic energy.

Our test pulse system produces conservative, multimegawatt electromagnetic pulses (1 megawatt of broadband energy) and is radiated preferably via a conical section antenna consisting of a parabolic reflector of 100 to 300 millimeters in diameter. A 25- X 25-centimeter-square metallic horn, flaring out to 100 centimeters square, will also provide a degree of performance. A.5-microfarad, special. low –

inductance capacitor charges up in about 20 seconds with the ion charger described in Chapter 1, “Anti­gravity Project.” and is modified as shown. Faster charging rales can be obtained by a higher-current system available on special request for more serious research Irom www. amazingl. com.

A high-power radio frequency pulse can be gener­ated where the output of the pulser may also be cou­pled to a full-size, center-fed. half-wave antenna tuned between 1 and 1.5 MHz. The actual length at 1 МН/ is over 150 meters (492 feet) and may be too large for many experiments. However, it is normal­ized for a radiation coefficient of 1, with all other schemes being less. The actual elements may be reduced in length by using tuned quarterwave seo tions consisting of a 75-meter (246-foot) length of wire spaced and wound on 2- to 3-meter pieces of polyvinyl chloride (PVC) tubing. This scheme pro­duces a pulse of low-frequency energy.

Please note, as stated, that the pulse output of this system will cause damage to computers and any devices using microprocessors or similar circuitry up to a considerable distance. Always use caution when testing and using this system—just being close can damage sensitive electronic equipment. Figure 25-2 provides a description of the strategic parts used in our lab-assembled system.

Capacitor

The capacitor (C) used for this type of application must have very low inherent inductance and dis­charge resistance. At the same time, the part must have the energy storage sufficient to produce the nec­essary high-powered pulse at the target frequency. Unfortunately, these two requirements do not go hand in hand. Higher-energy capacitors always will have more inductance than lower-energy units. Another important point is the use of relatively high – discharge voltages (V) to generate high-discharge currents. These values are required to overcome the inherent complex loss impedance of the series induc­tance and resistance of the discharge path.

The capacitor used in our system is.5 mfd at 50,000 volts with a.03-microhenry series inductance. Our tar­get fundamental frequency for the low-power nondis – ruptive circuit is 1 MHz. The system energy is400 joules, as determined by E = Ч2 CV?, with E at 40 Kv.

Inductor

The inductor can be easily made for a low-frequency radio puIse. The inductance shown as LI is a lumping of all stray connecting leads, the spark switch, the exploding wire disrupter, and the inherent inductance of the capacitor. This inductance resonates at a wide band of frequencies and must be able to handle the high-discharge current pulse (1 j. The value of the lumped value is around.05 to.1 Uh. The conductor sizes must take into effect the high pulse current, ide­ally equal to V X (C/L)b2.This fast current transition wants to flow on the conductor surface due lo the high-frequency skin effect.

You may use an inductor ot several turns for experimenting at Ihe lower frequencies along wilh a coupled antenna. Dimensions are determined by the air inductance formula: L = (10 X D – X N2 )/l, where D is the diameter in centimeters, 1 is the length in centimeters, and N is the number ol turns. A coil from 3 turns of 10 millimeters (.375 inches) of copper tub­ing on a 7.5-cenlimeter (З-inch) diameter spread out lo 15 centimeters (6 inches) will have a calculated inductance of.3 Uh.

Verification of Operation

To confirm that the device works properly, follow these steps:

1. Connect the output to a household 15-watt, 115 VAC fluorescent lamp.

Table 24-1 Fish stunner project parts

Ref. # Qty. Description DB #

Rl, 3 2 IK. ‘A-watt resistor (br-blk-red)

R2 470-ohm, ‘A-watt resistor (yel-pur-br)

R4 10K trimpot (103)

R5 ЮК control poi linear

R6.8 2 10-ohms,1 A-watt (br-blk-blk)

R7 2 1.8K. 3-watt metal-oxtde-seimcomluctor (MOX) resistors, two in a series

for 3600 ohms

Cl 10,000 mfd/ 16-volt electrolytic capacitor axial leads

C2 2.2 mfd/50-voU nonpolarized electrolytic capacitor

C3 .01 mfd/50-voll disk (103)

C5 2.200 mfd/25-volt vertical electrolytic capacitor

C4 3.9 mfd. 350-volt plastic capacitor #3 9M

DI. 2 2 IN914 silicon diodes

D3 LN5408 1 Kv. 3-amp rectifier

D4 Bright-green LED

Q1 1RF450 MOSFET transistor

LAB 1 DANGER HIGH VOLTAGE label

11 555 DIP timer 1C

Tl 24-volt 4 A with 240-volt primary 60 Hz. reworked per text #1UTR2412R

S1 SPST 3-amp toggle switch

PBUARD 2 ‘/4 X 5 X.1 grid perforated board, cut to size per Figure 24-3

WR20R Ci feet #20 vinvl wires, red

WR20B 6 feet #20 vinvl wires, black

WRBUSS 24 inches #20-inch bus wire

THERMO Thermo pad for mounting under Ql

LUOl 6-32 solder lug

TYEWRAP 2 12-inch heavy-duty tie wraps for holding Tl to frame

FRAME 11.5 X 1.75.063 A1 plate fabricated per Figure 24-5

BUI ‘/«" plastic clamp bushing

SWl I 6-32’/2 Phillips screw

SW3 1 6-32 X l/2-inch nylon screw

NUTl 2 6-32 kep nut

CAP1.2 2 3 ‘/z-inch plastic caps fabricated per Figure 24-7

EN1 10- x 3 ‘/2-inch OD schedule 40 PVC tubing

Connect ihe input to a 12 VDC source or a 4. Connect to the required electrodes and test it

battery capable of supplying 2 amps. out on a target fish. Use as suggested in Figure

24-8

Turn on the power and rotate the control, not­ing that the bulb lights and gets brighter as the control is turned clockwise. Also note the out­put indicator lighting.