Ramsey Electronics Rat Blaster RB1 Assembly And Instruction Manual

RB1 1

Ramsey Electronics Model No. RB1

Got a problem with furry intruders in your yard or garden? Here
is a professional strength repeller designed to send those pesky
critters running with their tails between their legs. A convenient,
nature friendly method of keeping animals away from where you
don’t want them

 Around 4 watts of screaming high frequency audio. Inaudible

to humans, but a terror to animals.

 3 settings for different levels of coverage
 Built-in piezo high efficiency speaker
 External trigger input for use with motion sensors and other

detectors.

 Operates on 9 to 15 volts DC or AC.
 LED indicator shows when unit is operating.
 Informative manual answers questions on theory, hookups

and uses - enhances resale value, too!

 Add our rugged metal case for years of outdoor or indoor

use.

RB1 2

PARTIAL LIST OF AVAILABLE KITS:
RAMSEY TRANSMITTER KITS

· FM10C, FM25B FM Stereo Transmitters

· AM1C, AM25 Transmitter
RAMSEY RECEIVER KITS

· FR1C FM Broadcast Receiver

· AR1C Aircraft Band Receiver

· AR2 Aircraft Band Receiver

· SR2C Shortwave Receiver

· AA7C Ac tive Ante n na

· SC1C Shortwave Converter
RAMSEY HOBBY KITS

· SG7 Personal Speed Radar

· SS70C Speech Scrambler/
Descrambler

· TT1C Telephone Recorder

· MD3C Microwave Motion Detector
RAMSEY AUDIO KITS

· SHA1C and SHA2 Headphone Amplifier kits

· UAM4 40 Watt Stereo Amplifier kit
RAMSEY AMATEUR RADIO KITS

· HR Series HF All Mode Receivers

· DDF1 Doppler Direction Finder Kit

· QRP Series HF CW Transmitters

· CW7C CW Keyer

· QRP Power Amplifiers
RAMSEY MINI-KITS

Many other kits are available for hobby, school, scouts and just plain FUN!
New kits are always under development. Write, call or visit
www.ramseykits.com for our free Ramsey catalog.

RB1 RAT BLASTER INSTRUCTION MANUAL

Ramsey Electronics publication No. MRB1 Revision 1.1

This Printing: July 2010

COPYRIGHT 2006-2010 by Ramsey Electronics, LLC, 590 Fishers Station Drive, Victor, New
York 14564. All rights reserved. No portion of this publication may be copied or duplicated
without the written permission of Ramsey Electronics, LLC. Printed in the United States of
America.

RB1 3

RB1

RAT BLASTER

Ramsey Publication No. MRB1

Price $5.00

TABLE OF CONTENTS

Introduction ..................................... 4

How Does It Work? ......................... 5

Learn As You Build ......................... 6

Parts List ......................................... 7

Parts Layout Diagram ..................... 8

Construction .................................... 9

Schematic Diagram ...................... 10

Initial Testing ................................. 15

Troubleshooting ............................ 16

Warranty ....................................... 19

KIT ASSEMBLY

AND INSTRUCTION MANUAL FOR

RAMSEY ELECTRONICS, LLC

590 Fishers Station Drive

Victor, New York 14564

Phone [phone]

Fax [phone]

www.ramseykits.com

RB1 4

INTRODUCTION TO THE RB1 RAT BLASTER

This is a practical project for people with problems with furry intruders in their
yard, not just rats. The Rat Blaster is useful in repelling all kinds of wildlife. The
list includes deer, dogs, cats, all rodents, and even some insects. This is the
safest, most effective way to repel animals from eating your shrubbery or
burrowing in your carrot patch. It is also a great help at keeping little surprises
out of your lawn left by the neighbor’s pets.

Instead of just generating a single constant tone like many competitive units on
the market, the RB1 creates a warble tone that varies in frequency. This sound
is enough to drive any person crazy if they could hear it. When the RB1 was in
its design stages, the frequency was low enough to hear. Three offices up and
two doors between was not enough to prevent irritation and complaints from
associates. Just imagine what it can do with no obstructions!

This unit is set outside facing the area desired to be protected. It then covers an
area in the shape of an oval. On the low frequency setting, it will cover an area
of approximately 4000 square feet. On the high frequency setting, it covers an
area of around 2500 square feet. The advantage of running the high frequency
setting is that it is well out of the human hearing range. The low frequency
setting is just at the limit of hearing and can be irritating to some people with
acute hearing. The reason the low frequency signals cover a larger area is due
to a combination of how good the animals ears are, and how directional the
sound is from the transducer.

Built into an easy to mount case of durable construction, the Rat Blaster will
operate for years, providing your yard and garden with animal protection. This
is truly the gardener’s dream come true!

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HOW DOES IT WORK?

Here is where we get into a little circuit analysis. If you just want to plug it in and
start scaring off critters, you can skip this section. Otherwi se here is some
insight into why and how this RB1 works. We will use the schematic located at
the center of the manual to analyze the circuit.

We will begin with the IC marked NE555, U1. This is a simple, free running
oscillator circuit which is used to generate the lower frequency warble rate of
the signal. This rate varies from around 1Hz to 10Hz. The output of this
oscillator is a 12V square wave until it is sent through R2 into C7. These parts
filter the waveform into a sawtooth waveform.

U2, the XR-2209 is set up to be a voltage controlled oscillator running between
15kHz and 30kHz. The higher the voltage seen on pin 4 of U2, the higher the
frequency produced on pin 7 of U2. When the low frequency sawtoo th signal
from U1 is sent to pin 4, the high frequency signal of U2 modulates or “warbles”
at a rate of U1’s output frequency.

S2 controls the average DC voltage of the sawtooth by adjusting the rate of
discharge of C7. The less resistance seen from pin 4 to ground, the faster C7
discharges. The faster C7 is discharged, the lower the average volt age of the
sawtooth waveform is. In turn, the lower the average voltage on the sawtooth,
the lower the average frequency on pin 7 of U2 allowing this unit to cover a
larger area.

The output of U2 is then sent to some logic which enables or disables the
speaker driver circuitry depending on what signal is seen on pin 2 and 6 of U3.
When these pins are at a logic ‘0’, or 0 volts, the transducer driver is enabled,
and when it is ‘1’, or 12 volts, it is disabled.

The speaker driver section consists of a push-p ull circuit controlled by U3:D, B,
and C. U3:B inverts the signal from U3:A so that when pin 3 is high (12 volts)
pin 4 is low (0 volts). U3:D and U3:C are set up as inverting buffers to drive the
transistors that drive the transducer.

The speaker driver also consists of the four transi stors surrounding SP1 which
provide more power capability than what U3 offers. When U3 pin 11 is high, Q4
is turned on, and Q1 is turned off. This presents about 12 volts on one side of
the transducer. While pin 11 is high, pin 10 is low, which turns on Q 2 and Q3
off, pulling the other lead of the transducer to near 0 volts. Now there are
almost 12 volts across SP1, allowing the transducer to produce sound. On the
next half of the cycle, the transistors that were off are turned on, and the ones
that were on are shut off. Now there are 12 volts across the transducer
connected in the opposite direction from before. This is all done at a rate of
around 15,000 to 30,000 times a second, producing the high frequency signal
to scare off the beasties.

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RAMSEY “LEARN-AS-YOU-BUILD” ASSEMBLY STRATEGY

Be sure to read through all of the steps, and check the boxes as you go to be
sure you didn't miss any important steps. Although you may be in a hurry to see
results, before you switch on the power, check all wiring and capacitors for
proper orientation. Also check the board for any possible solder shorts, and/or
cold solder joints. All of these mistakes could have detrimental effects on your
kit - not to mention your ego!

Kit building tips:

Use a good soldering technique - let your soldering iron tip gently heat the
traces to which you are soldering, heating both wires and pads simultaneously.
Apply the solder to the iron and the pad when the pad is hot enough to melt the
solder. The finished joint should look like a drop of water on paper - somewhat
soaked in.

Mount all electrical parts on the top side of the board provided. This is the side
that has little or no traces on it. When parts are installed, the part is placed flat
to the board, and the leads are bent on the backside of the board to prevent the
part from falling out before soldering (1). The part is then soldered securely to
the board (2-4), and the remaining lead length is then clipped off (5). Notice
how the solder joint looks close up, clean and smooth with no holes or sharp
points (6).

NOTE TO NEWCOMERS: If you are a first time kit builder you may find this
manual easier to understand than you may have expected. Each part in the kit
is checked off as you go, while a detailed description of each part is given. If
you follow each step in the manual in order, and practice good soldering and kit
building skills, the kit is next to fail-safe. If a problem does occur, the manual
will lead you step by step through the troubleshooting guide until you find the
problem and are able to correct it.