Supplementary Rpplication Note

This device can provide hours of entertainment for adults and children alike. For example, a small box containing an oscillator at a frequency of 25 kHz

J1 headphone jack

R19/S1 on/off and volume control

R12 frequency tuning


Supplementary Rpplication Note

Supplementary Rpplication Note

Unit without parabolic reflector where transducer is mounted as shown in Fig. 26-4

Figure 26-7 Final assembly without a reflector

could be well hidden somewhere. The highly direc­tional characteristics of the device with its ability to respond to various signal levels enable a quick bear­ing to be made 011 the hidden source and the fun begins. It should be noted that ihe detection range could be in excess of a quarter-mile! This allows great flexibility in hiding the oscillator, using only your imagination for making detection difficult. Along with my children and friends. T have had many enjoy­able hours and good laughs playing with this equip­ment.


You may easily record the output lo a recording device by connccling the auxiliary input to the head­phone output jack. A CiY’’ adapter can be used for simultaneously plugging in the headset to monitor the recorded sounds. Two sets of headphones can be used with the adapter, and the output impedance is 8 ohms.

Table 26-1 Ultrasonic microphone parts

Ret # Qty. Description DB#

Rl, 21 2 10 ohm, ‘/< watt (br-blk-blk)

R2 3.9K, ‘/4 watt (or-wh-red)

R3 10 megs, 4* watt (br-blk-blue)

R4,8,18 З 10K, ‘/4 watt (br-blk-or)

R12 ЮК, 17-millimeter pot

R5,7,10,11,14,15 6 lOOK,»/4watttbr-bIk-yel)

R6, У 2 470K. ‘/4 watt (yel-pur-yel)

R13 2.2K,’/« watt (red-red-red)

R16 1 meg, ‘/■> watt (br-blk-grn)

R17 4.7K, ‘/4 watt (yel-pur-red)

R19/S1 10K, 17-millimeter linear pot and switch

R20 47 ohm, ’/4 watt (yel-pur-blk)

Rd Select for dampening transducer circuit—10 to 47K, ’/4 watt

Cl 10 mfd, 25-volt vertical electrolytic capacitor

C2. t2 6 .01 mfd, 25-volt disk or plastic capacitor

D1 1N914 smatl-signat diode

C8 .047 mfd, 50-volt ptastic capacitor

C5,7,13,14 4 .1 mfd, 25-volt disk or plastic capacitor

C9,16 2 100 mfd, 25-volt verticat electrotytic capacitor

C15 1,000 mfd, 25-vott vertical etectrolytic capacitor

LI 27 millihenry mduclor #IU27H

Qt J202 n-channel FET

11 LM074 4-second OP amp DIP

12 LM386 audio amplifier DIP

J t 3.5-millimeter stereo audio jack wired for mono

TD1 25 kHz acoustical receiving transducer #1UTR8925

SHt 18 inchcs Shielded mike cable

PB1 PC or.1 gnd perforated vector board, 2.25- X 2.25-inch

BAF1 Thin piece of 2.25- X 2.25-inch plastic for insulating

BtJl 1 X ‘/г x 3/if, watl neoprene bu&hing

CL I Battery clip with 12-inch leads

PARA12 Optional parabolic reflector #IUPARA12


Supplementary Rpplication Note

This project shows how to build a directional, hand­held device capable of driving off both wild and domestic animal pests (sec Figure 27-1). This device produces high-pressure-level sound at complex fre­quencies mostly above that of human hearing. This sound is painful to many animals as their hearing is much more acute than humans. The unit is tunable and can also be adjusted to be very annoying to peo­ple when exposed at close range.

The circuitry is housed inside an easily obtainable piece of polyvinyl chloride (PVC) tubing and resem­bles a large ray gun. The output controls are on the rear panel with the batteries in the handle. Expect to spend around $25 to assemble this sound gun. All the parts are readily available, with the hard-to-find items available at www. amazingl. com.

Caution: Exposure below 20 kHz at a sound-pres — sure level of 105 decibels (db) in excess of 1 hour may cause a hearing impairment.

This project shows how to construct a moderately powered, directional source oi continuous, adjustable, high-frequency, time-variant acoustical shockwaves. The output energy of the devicc is conservatively rated at 125 db. The frequency is programmable or is con­stantly sweeping at an internal preset rate and is vari­able approximately from an audible 5 to 20 kHz. The unit is intended for use as a research tool in the study of animal behavior, acoustical experimentation, or as a source of intense, directional, acoustical, high-fre­quency sound for other scientific and laboratory appli­cations. The device is excellent for use in agricultural applications such as flushing out rats and other rodents from granaries, silage bins, chicken coups, and so on.

It is to be used with discretion and not treated as a toy. Caution must be used as exposure to most people causes pain, headaches, nausea, and extreme irritabil­ity (younger women are especially affected). Do not, under any circumstances, point the unit at a person’s ears or head at close range, as severe discomfort and possible ear damage may result. Usage on dogs and other animals must be done with discretion to avoid excessi ve d iscom fori.