Design And Construction Of An Electric Bug Zapper

ABSTRACT

A bug zapper, which is also called an electrical discharge insect control system, electric insect killer or (insect) electrocutor trap, is a device that attracts and kills flying insects that are attracted by light. A light source attracts insects to an electrical grid, where they are electrocuted by touching two wires with a high voltage between them.

This work is aimed at reducing the number of mosquitoes through the use of electronics. The work entails the design and construction of a high voltage circuit (mosquito Zapper) which can electrocute mosquitoes. It also consists of a power supply unit which is mainly used to charge the battery. The mesh dimension is 33cm by 23cm and had one inner mesh with 2 outer ones. The controls are made up of a push button and 2 mini switches and have 2 indicators for charging and power.

TABLE OF CONTENTS

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWLEDGEMENT

ABSTRACT

TABLE OF CONTENT

CHAPTER ONE

1.0      INTRODUCTION

1.1      BACKGROUND OF THE PROJECT
1.2      AIM OF THE PROJECT
1.3      OBJECTIVE OF THE PROJECT
1.4      SIGNIFICANCE OF THE PROJECT
1.5      PURPOSE OF THE PROJECT
1.6      APPLICATION OF THE PROJECT
1.7      ADVANTAGES OF THE PROJECT
1.8      PROBLEM/LIMITATION OF THE PROJECT
1.9      PROJECT ORGANISATION

CHAPTER TWO

2.0     LITERATURE REVIEW

2.1      REVIEW OF RELATED STUDIES

2.2      REVIEW OF RELATED TERMS

CHAPTER THREE

3.0     CONSTRUCTION METHODOLOGY

3.1      SYSTEM CIRCUIT DIAGRAM

3.2     SYSTEM OPERATION

3.3      CIRCUIT DESCRIPTION

3.4      SYSTEM CIRCUIT DIAGRAM

3.5      CIRCUIT OPERATION

3.6      IMPORTANCE AND FUNCTION OF THE MAJOR COMPONENTS USED IN THIS CIRCUIT

3.7      POWER SUPPLY UNIT

CHAPTER FOUR

RESULT ANALYSIS

4.0      CONSTRUCTION PROCEDURE AND TESTING

4.1      CASING AND PACKAGING

4.2      ASSEMBLING OF SECTIONS

4.3      TESTING

4.4.1 PRE-IMPLEMENTATION TESTING

4.4.2  POST-IMPLEMENTATION TESTING

4.5      RESULT

4.6      COST ANALYSIS

4.7      PROBLEM ENCOUNTERED

CHAPTER FIVE

5.1      CONCLUSION

5.2      RECOMMENDATION

5.3      REFERENCES

Bug zapper

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An outdoor bug zapper

A bug zapper, more formally called an electrical discharge insect control system, electric insect killer or (insect) electrocutor trap, is a device that attracts and kills flying insects that are attracted by light. A light source attracts insects to an electrical grid, where they are electrocuted by touching two wires with a high voltage between them. The name comes from the characteristic onomatopoeic zap sound produced when an insect is electrocuted.

Contents

• 1 History
• 2 Design
  • 2.1 External traps
  • 2.2 Scattering
  • 2.3 Hand held type
• 3 See also
• 4 References

History

Early model prototype fly zapper circa 1911, conceded to be too expensive to be practical

In its October 1911 issue, Popular Mechanics magazine had a piece showing a model “fly trap” that used all the elements of a modern bug zapper, including electric light and electrified grid. The design was implemented by two unnamed Denver men and was conceded to be too expensive to be of practical use. The device was 10 by 15 inches (25 by 38 cm), contained 5 incandescent light bulbs, and the grid was ¹⁄₁₆-inch (1.59 mm) wires spaced ¹⁄₈-inch (3.17 mm) apart with a voltage of 450 volts. Users were supposed to bait the interior with meat.^[1]

According to the US Patent and Trademark Office, the first bug zapper was patented in 1932 by William M. Frost;^[2]

Separately, Dr. William Brodbeck Herms (1876–1949), a professor of parasitology at the University of California, had been working on large commercial insect traps for over 20 years for protection of California’s important fruit industry. In 1934 he introduced the electronic insect killer that became the model for all future bug zappers.^[3]

Design

Indoor bug zapper which can for example be used in a bedroom

Bug zappers are usually housed in a protective cage of plastic or grounded metal bars to prevent people or animals from touching the high voltage grid. A light source is fitted inside, often a fluorescent lamp designed to emit both visible and ultraviolet light, which is visible to insects and attracts them.^[4] The light is surrounded by a pair of interleaved bare wire grids or spirals. The distance between adjacent wires is typically about 2 mm (0.079 in). A high-voltage power supply powered by mains electricity, which may be a simple transformerless voltage multiplier circuit made with diodes and capacitors, generates a voltage of 2,000 volts or more, high enough to conduct through the body of an insect which bridges the two grids, but not high enough to spark across the air gap. Enough electric current flows through the small body of the insect to heat it to a high temperature.^[5] The impedance of the power supply and the arrangement of the grid is such that it cannot drive a dangerous current through the body of a human.

Many bug zappers are fitted with trays that collect the electrocuted insects; other models are designed to allow the debris to fall to the ground below. Some use a fan to help to trap the insect.

External traps

These traps are not effective at killing biting insects (female mosquitoes and other insects),^[6][7] being much more effective at attracting and killing other harmless and beneficial insects. A study by the University of Delaware showed that over a period of 15 summer nights, 13,789 insects were killed among six devices. Of those insects killed, only 31 were biting insects.^[8] Mosquitoes are attracted to carbon dioxide and water vapor in the breath of mammals, not ultraviolet light.^[7] However, there are now bug zappers that emit carbon dioxide or use an external bait, such as octenol, to better attract biting insects into the light.

Scattering

Research has shown that when insects are electrocuted, bug zappers can spread a mist containing insect parts up to about 2 m (6 ft 7 in) from the device. The air around the bug zapper can become contaminated by bacteria and viruses that can be inhaled by, or settle on the food of people in the immediate vicinity.^[9][10] The US Food and Drug Administration (FDA) advises that the bug zapper should not be installed above a food preparation area, and that insects should be retained within the device.^[11] Scatter-proof designs are produced for this purpose.

Hand held type

Battery powered bug zappers are manufactured, often in the shape of a tennis racket with which flying insects can be hit.^[12]

See also

• Electric flyswatter
• Fly-killing device
• Insect repellents from natural sources
• Moth trap
• Nematocera
• Personal protective equipment

References

• Windsor, H. H., ed. (October 1911). “An electric death trap for the fly”. Popular Mechanics. 16 (4): 464.
• · US US1871978A, Frost, William M., “Insect electrocutor”, issued 1932-08-16
• · “Electric Chair For Insects Helps Farmers”, 1990 march
• · “Reasons Why Are Bugs Attracted To Light”. Hoofia.
• · Freudenrich, Craig. “Bug Zappers”. How Stuff Works. Retrieved 2009-10-22.
• · sciencedaily.com: “Snap! Crackle! Pop! Electric Bug Zappers Are Useless For Controlling Mosquitoes, Says UF/IFAS Pest Expert” July 30, 2013.
• · “Bug Zappers are Harmful, Not Helpful”. Horticulture and Home Pest News. Iowa State University. IC-475 (15). 1996-06-14. Retrieved 2009-10-22.
• · “Full text of “Density and Diversity of Nontarget Insects Killed by Suburban Electric Insect Traps””. archive.org. Retrieved 2015-12-29.
• · “Can bug zappers help transmit diseases?”. HowStuffWorks. Retrieved 30 April 2009.
• · Urban, James E.; Alberto Broce (October 2000). “Electrocution of House Flies in Bug Zappers Releases Bacteria and Viruses”. Current Microbiology. Kansas State University. 41 (4): 267. doi:10.1007/s002840010132. PMID 10977894. Archived from the original on 2013-06-11. Retrieved 2009-10-22. bug zappers not only pose an immediate threat because of the release of bacteria and viruses, but they also release insect particles which are potential allergens or which cause various respiratory conditions
• · “Chapter 6: Physical Facilities; Insect Control Devices, Design and Installation; 6-202.13”. FDA Food Code 2009: Annex 3. U.S. Food and Drug Administration. 2009. Retrieved 2013-06-23.
• Does Electrifying Mosquitoes Protect People From Disease? thealtlantic.com, 5 May 20

Design and Construction of a Tripler Circuit for a Mosquito Zapper

1M. Alpha., ²Jummai .D. Makama., ³Adoyi .Emmanuel ⁴T.O. Daniel .,

5Islamiyat .T. Salaudeen, ⁶Kure .N., ⁷Bello .I.A.

1&5Department of Physics, Federal University of Technology Minna, P.M.B 65, Minna

4Department of Physics/geophysics, federal University Ndufu-Alike, Ikwo, P.M.B 1010, Abakaliki, Nigeria

6Department of Physics,Kaduna State University 2&7Department of Physics Ahmadu Bello University 3Department of Physics, Nigeria Defence Academy, Kaduna

ABSTRACT: This work is aimed at reducing the number of mosquitoes through the use of electronics. The work entails the design and construction of a high voltage tripler circuit for a mosquito Zapper which can electrocute mosquitoes. It also consists of a power supply unit which is mainly used to charge the battery. The mesh dimension is 33cm by 23cm and had one inner mesh with 2 outer ones. The controls are made up of a push button and 2 mini switches and have 2 indicators for charging and power.

Keywords: Zapper, Tripler, Mosquito

I.            INTRODUCTION

A mosquito zapper is a device used for killing mosquitoes using high voltages [4]. The mosquito zappers are in different shapes and sizes but consist of the same basic building blocks namely:

1. A high voltage generating circuit
2. A mesh net assembly
3. A power supply unit
4. A control device

The high voltage circuit generates voltages in the range of 700 – 1000 volts to a mesh assembly which traps the insects. The power supply is either battery or rectified voltage source. The control device is a switch to operate the Zapper. The mosquito Zapper has come a long way since the American National malaria eradication programme in 1947 (Centre for disease Control, 2012) [2]. The communicable disease centre CDC welcome ideas and measure that could bring about mosquito reduction and so therefore many initiatives came to be which falls under the following:

1. Mosquito repellents
2. Mosquito screening methods
3. Mosquito anti lava methods

The repellent methods dealt with the use of chemicals to repel mosquitoes. Such repellent creams like “odoms” provide short duration measures. The screening methods include the development of nets and mesh wires, though expensive but effective. Lastly the anti-lava methods which are biological in nature have to do with environmental issues that are making sure that the environment is clean and no water left in cans and so on around where mosquito lava can grow.[1]

DDT was the insecticide used mostly in American mosquito reduction programs in the 1940„s and at 1951 the country was free of malaria. The World Health Organization (WHO) took steps in that direction but was unsuccessful which brought about the various technics mentioned above. The mosquito Zapper is a screening technique with an electronic innovation to control mosquitoes entering homes. American Heritage® Dictionary of the English Language, Fifth Edition. (2011). [5]

II.            MATERIALS AND METHODS

General Circuit Diagram and Its Operation Principle

The main body resistance of most bugs and mosquitoes fall within the range of 0.70 – 0.75 Ω [3] and the required Zapper voltage is from 600 to 1200 volts ac. Figure 1.1 is the general circuit diagram of the Zapper. The Zapper Circuit functions by the following principles; when the battery power is switched on, the

RC oscillator produces a waveform like a square wave which switches transistor T1 On and Off and as such allows the battery current to be switched to and from the centre tapped transformer which sees the voltage as an AC Voltage. This voltage is induced into the pulse transformer secondary winding through electromagnetic induction. And because the transformer is in step up mode, the voltage is increased by 100 times to give an output which when tripled produces the required voltage that can electrocute a bug or insect. The output of the Tripler is connected to 2 meshes whereby the inner mesh called the hot mesh carries the high voltage while the outer meshes carry a ground potential.

Figure 1.1 General Zapper circuit diagram

Tripler Circuit Design

The Tripler circuit used in this work has a rating between 2 mA -18 mA. The capacitors are C104 while the diodes were 1N4007. The basic Tripler circuit is as shown in Figure 1.2. The Tripler circuit is capable of multiplication and as such the output of the transformer when tripled will bring about the required voltage to zap a bug at the Tripler output.

Figure 1.2 Transfomer and Tripler Circuit Diagram

Power Supply Realization

Since a 3.9 V battery is the target load, the transformer of 12 V is chosen to meet the total power need of this work. The charging circuit can be a single component such as a 7806 regulator or a LM317. Designing the power supply, a 12V, 500 mA transformer was purchased from the local electronic market and abridge rectifier of 1A was selected from the data book. The output was filtered by a 100µf capacitor and regulated with a 7805 regulator to charge the 3.9 V battery.

As shown in Fig 1.3 the power supply circuit consists of a 220/12 V transformer with a bridge rectifier of 4 diodes, a filtering capacitor, and a 6volt regulator that is connected in parallel to a 4.5 V zener diode with two resistors R1, R2, connected in series to two LED and a 3.9 V dc battery which is also in parallel to the zener diode that is fed in such a way to protect the amount of voltage charging the battery to a maximum power of 3.9 V dc.

As the charger circuit is connected to the socket outlet the LED1 will glow indicating the presence of power As the switch (sw1) is closed the output to battery is filtered to ensure a pure DC is archived as the current flows across the LED that is limited by the resistor R2, switch (sw2) is further closed allowing the LED2 to glow and indicate the presence of current and workability of the circuit.

The push button switch is just for additional design purpose of temporal uses. The filtered pure DC output is further sent to the inverter circuit or simple oscillator circuit through the positive output of the battery to the centre tap of the step up transformer and the negative output of the battery to the emitter of the switching transistor.

Figure 1.3 Power supply unit

Temporary construction

The construction of the circuit was initially carried out on bread board as shown in Figure 1.4 with the RC oscillator and the switching transistor mounted first then the transformer mounted and the circuit was checked for correct polarity before continuing.

Figure 1.4 Assembly of temporary circuit

This stage was quickly tested and it was observed that the output of 334.2 V appeared on the meter. The Tripler circuit was then carefully assembled and the complete circuit was tested with a set of mesh for fear of the high voltage damaging the meter because the range of the ac was 700 ac on the meter. The mesh was carefully separated and checked for short circuit. The circuit was powered and a stunned fly was used as a test insect and it was executed immediately. The picture in Figure 1.5 shows the test setup

Figure 1.5 Test Setup

Permanent Construction

The temporary construction after being tested for outputs and performance as regards electrocuting of insects, the arrangement of the circuit was then transferred to the vero board for a permanent circuit where the component was soldered. A stripped vero board was used for the work and as the components were placed one after the other, after a careful check for the layout plan, they were soldered into place and strip lines etched to make the component form a circuit. The polarity of the transistor was checked before soldering. After this, the transformer was placed correctly noting the primary and secondary windings before soldering. The strip board was then etched to separate the transformer terminals along the strip line. The Tripler circuit was then carefully arranged and then soldered before the etching so as to ensure compliance with the circuit diagram. PN junction diodes used were checked for their polarities then soldered.

Tapping wires to the mesh were taken from the terminals of the major capacitor to the meshes. The final circuit was finally checked for error before it was then tested for output. The power supply was also then constructed from the schematic diagram by first placing the diodes, and then the LEDs and switches were also connected using tapping wires

Figure 1.6 Zapper circuit on permanent (vero) board

After this test, the circuit was then connected beginning with the oscillator (RC) as shown in Figure 1.7

Figure 1.7 Rc Oscillator Test

A test on the RC oscillator showed a low frequency distorted saw wave which is used to switch transistor T1 thereby driving the transformer with collector current Ic

III.           MEASUREMENTS/RESULTS

During the construction of this work some preliminary measurements were carried out on the components to be sure they are in good working conditions. Table 1.1 shows the component test.

Table 1.1 Component test

IV.            CONCLUSION

In conclusion of this work after looking at the design and the results obtained, it can be observed that many difficulties were encountered with the best possible oscillator component. It took several trials to achieve an oscillation that can give a reasonable voltage at the transformer output. Sometimes a high voltage could be obtained but cannot give reliable output at the Tripler than the transistor choice of which the problem was later understood to be that of the transistors operating frequency specification and after these two problems the oscillator worked very reliably and the overall output became steady enough to electrocute by a spark of high voltage.

RECOMMENDATION

It is recommended that further work should be done involving the use of wider mesh and increase in transistor power to allow multiple windows zappers to be operated from one control.

REFERENCES

[1].           Alvin D. Willbanks (2000) Infrared Insect Mosquito Killing System. Retrieved from http://www.google.com/patents/US6050025

[2].           Christopher              Buckley                (2003)               History                of                the               Bug                Zapper.               Retrieved              from http://www.forbes.com/forbeslifemagazine2003/0526/088.html

[3].           Centre for Disease Control and Prevention (2012) Elimination of malaria in the United States1947-1951. Retrieved from http://www.cdc.gov/malaria/about/ history /elimination /us.html

[4].           F.Folmer and Harrison L.Chapin (1934) Insect Exterminator. Retrieved from http://www.google.com/patents/US1962439

[5].           Zapper.(n.d.) American Heritage® Dictionary of the English Language, Fifth Edition.(2011). Retrieved from http://www.thefreedictionary.com/zapper