Automated Solar Pesticide Dispensing System Engineering Essay

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The aim of this project is to automate and design a new method of applying pesticide to cattle and game that are more effective and adaptable for use under different conditions. Taking in consideration in the design the high prices for pesticides and the problem of effective treatment for all types of animals .

A sun panel will be used to charge the entire system. The pesticide will be sprayed on the cattle by using a pump. The system is powered by a 12V acid battery. When an animal passes by the sensors it will activate the pump. It will be very efficient for reason it will not waste pesticide. The type of pesticide this system will be using is a liquid base.

The system will be designed according to every farmers needs. For example it depends on the amount of cattle on the farm this system has been designed for 350 cattle.

A demonstration model will also be manufactured in order to demonstrate the system.

There are many different pesticide systems that can be used. But there is not a system that can efficiently be used for cattle and game. This system can even be used for giraffes. It can be easily be modified for different situations. It can be implemented on a cattle farm. A lot of system can only cater for animals of a certain height. This system can cater for any animal of any height.

We have a small farm just outside of Brits. For pesticide treatment we use Duncan applicators. But there were several problems:

Some of the problems that were identified included but was not limited to, rain. When it rains the pesticide becomes diluted. The pesticide becomes full of dust and other items if the wind blows. The pesticide is also in direct contact with all the elements including direct sun light that tend to evaporate some of the pesticide and lessen the efficiency of the pesticide . The Duncan applicators do not work for giraffes. The Duncan applicator is way too small to treat all the cattle and bigger game for instance Eland. The giraffes don't bend down that low and don't get treated with the Duncan applicator.

The Eland tends to chase each other away from the applicator when one uses salt leaks and other food to draw them closer to the applicator. This have the effect that the dominant male gets treated but the rest of the herd suffer from pest infections. When this happen one tends to lose most of the new born calves due to the fact that when for instance a tick bites the teats of the female animals then the teats become over sensitive. This condition lead to calve lost because the female animals will not allow the calves to drink from them.

Then there is also a problem to treat animals for instance some game do not except additional foods and do not eat from the Duncan applicators for instance Hartebeest . One need a system to spray them on their way to the water points in the game path that they use because they will not make use of other food .So I wanted a system that could cater for all these different needs and conditions of different kinds of animals.

Literature Review:


The literature review investigate the different methods of pesticide applicators. This investigation concentrates on the function, benefits and safety of the applicators and design my own applicator with this information in mind. It was clear that there is a huge need for reliable applicators because of the growth of game farms especially in South Africa that don't waste insecticides as it is not cheap any more and a lot of money can be safe with proper control and application. It became clear that insecticides are one of the hidden costs that can make a huge difference to your overall profits. It also come to my attention that most of this applicators are used were duel function and are not only used for general farm animals( cows) but also for game . Another aspect that comes to light was that one need to take care of the environment and use oxpecker friendly and environmental bio- degradable insecticides to prevent long term effects on the natural environments where most of these applicators are used . Applicators become part of modern farming for controlling internal and external pesticides on live stock due to the fact that we use smaller farms to produce milk, meat and hides and limited the natural movement of game by means of fences and smaller farms . These limitations concentrate pests and natural insects to become concentrated in the limited area and they increase to huge numbers that are not natural any more. The only way to get rid of this concentration of pests is to control them by means of treatment and prevention. It is in this area that applicators play a vital role and can prevent huge losses to animals and live stock. The more we understand the cycles of pesticides and farming the better we can make use of applicators to control pesticides and the higher the demand will be in future for these devices .

Now knowing that pests need to be controlled one can take an in-depth look at the current devices and see if they function according to the needs and requirements. Currently there are several ways of getting rid of pests on live domestic stock and game. Current applicators make use of dry formulas such as ear tags, dust, dust bags, powders and back rubbers. Other applicators use liquid pesticides for instance a Duncan Applicator that use natural flow of liquid or mechanical devices that use mechanical pump action to spray liquid pesticides. Liquid solutions can also be sprayed from a back carry pack or even from moving vehicles. Today Air guns are also used with darts where additional treatments are needed.[1]

Ear tags:

Ear tags is commonly used on cattle. There are many types of ear tags with different compounds. Some ear tags may not be used on lactating dairy cattle. Others may be used on beef and lactating dairy cattle and calves. For optimum use each ear of the cow must have a tag. But for a calf one tag is enough. One tag will last about 3-5 months. [2][3]

There is several disadvantages: Firstly rounding up of the cattle it may seem as an easy task but if there is over 400 cattle it becomes challenging. The ear tags manly protects the face and horns of the animal from face flies[Figure 3] and horn flies[Figure 4], not the rest of the body. Another problem is during the rainy seasons then the tag does not last as long. It is not easy to use ear tags on game. The problem is capturing them can become a very expensive exercise.

And some ear tag manufacturers use very low levels of concentrated insecticide which leads to a population of flies that is immune to that specific insecticide.[See figure 2][4]

How to insert an ear tag:[5][Figure 1]

Figure 2

Figure1 Figure 3

Figure 4

Dust bags:

Dust bags[Figure 5] is also a great way to fight pesticide. A dust bag is exactly what the name implies. It is a bag filled with insecticide dust, some can hold up to 11kg of dust. So it does not have to be exchanged frequently. Weather does not really have an impact on the bags because they are covered by canvas covers, so the dust stays dry.

Dust bags are sold as a kit which consist of a dust bag, weather resistant rope and a plastic cover. Refill kits that contain insecticide dust is also available.

There are two types of dust bags Large rectangular bags about 90cm by 60cm.

They are usually hung across gates or door ways. The second type is cylindrical dust bags manly designed to be hung in loafing areas and other spots where cattle can rub their bodies or butt them. The dust bag is very good for getting rid of pesticide that covers the body and face of the animal. As a cattle rub the bag the insecticide passes through the holes of the bag covering the animal. The disadvantages of this system is it does not cover for all heights of cattle. And if it gets wet the dust solidifies.[6]

Figure 5

Back rubber:

Back rubber consist of a chain as the basis for the cattle rub. Which is then wrapped with burlap which is an absorbent material. Wire is then twisted around the material to keep it in place. To optimize this system mop hear is dangled from it or any other type of absorbent material. The burlap is moistened with an insecticide-oil solution. A water base solution will evaporate to quickly.

The system is suspended between two poles or trees. About 1.2m from the ground and must sag about 45cm. Back rubbers should be recharged about every 2-4 weeks with a proper insecticide-oil formula. This system is usually located near a watering hole or salt lick. The disadvantages of this system is that large cattle can tear the burlap material. And it can be difficult to get the cattle to use it .[7]

Duncan Applicator:

A Duncan applicator[Figure 6] is manly used for antelope, but with the cattle adaptor plate it can be used for cattle and game. The insecticide solution is poured in the container on top of the system. It slowly leaks out of a small hole of which the size can be controlled by a screw. The insecticide runs down the pole very slowly. When cattle comes to eat out of the bucket they rub against the pole. There are several disadvantages, because if it rains the insecticide is diluted and not as effective. And even if there is no cattle near the system it will continue to run. It cannot treat a large heard of cattle and the pole of the applicator have to touch the animal before it has any effect [8]

Figure 6

Dipping of Cattle:

This is a very effective method for controlling pesticides. However, if not done correctly effectiveness is reduced. It is very important to mix the right amount of chemicals with water. To much of the chemical is a waste of money,and can cause death to calves and weak animals. Residue can be deposited in the meat and degrade its value. Once the water and chemicals are in the dip about 30 cattle must past through the dip just to stir the mixture,so these cattle should return to main mob and be dipped again. The dip level should be monitored constantly. If the level drops water and chemicals should be added. The product container will indicate the amount of water and chemicals to be mixed when adding to the dip. Rain causes a serious problem for this system, because the dip level rises and the chemicals become diluted.[See figure 7][9]

Figure 7

Mechanical spray system:

The cattle driven through a passage way where the spray nozzles are arranged so that each animal is sprayed as they pass through the chute. The amount of spray depends on the weight of the animal. The floor of the system consist of a horizontal peddle which is connected to a spring. The peddle is pressed downward by the weight of the animal which compresses the spring. The peddle is also connected to a rod which controls the valve that determines the amount of flow. So the heavier the animal the more insecticide is sprayed.[See figure 8][10]

Figure 8

Hand spraying:

Is only practical for small number of cattle. This method is very effective, but has some disadvantages because it is very time consuming and need more laborers which can cost a lot of money. [11]

Spray system that works continuously:

This system is also used when cattle are driven through a chute. There are some difficulties with this system because you have to ensure that the animal receive spray but not to much. The animals must move continuously through the system. If an animal pauses in the system it can receive to much spray. When the gaps between the animals are to big spray is wasted.[11]

Mist sprayer :

Sprays a large amount of insecticide in the form of mist. Some of them can be quite big. Spray Innovations is just one of many brands. The mist can be sprayed anywhere on the animals, in the feed lots and the pens. This system is powered by an engine. It sprays a large amount of mist at a time, can treat a large number of cattle at once. The disadvantage of this system is there is a lot of waist. To cover the largest area the system is loaded onto a truck or trailer. As the truck move the system sprays.[12]

Figure 10 Figure 9

Figure 11

Injectables :

Injectables is also a method to get rid of pesticide. The amount to be injected depends on the animals weight for example Moxidectin is use as follow 0.2mg/kg.[13]

Injecting methods:

There are several ways of injecting the animal. The animal can be injected with a normal needle or with a dart gun [See figure 12]. Injecting each animal can be very time consuming. By using a dart gun it becomes very expensive. Injectable insecticide is only effective on sucking lice not biting lice. It also has an impact on non-targeted species such as dung beetles.[13][11]

Figure 12

Safety :

Storage of chemicals:

Store pesticides in a locked facility where children cannot reach them.Read the labels on the pesticide container so that it can be stored correctly.Pesticides should not be stored near food. The pesticides should be kept dry and out of direct sun light. Those that come in boxes should be stored on wooden pallets.[14]

Conceptual ideas:


Concept 1:




Figure 13

1 Sensor.

2 Box Containing the circuit board, battery, pump, and container for the poison.

3 Tube with small holes from where the poison will spray.

4 Normal Duncan Applicator.


A Duncan Applicator is used to feed animals, in this case it is just modified a bit. When the animal comes to feed the sensor on top of the Duncan Applicator will detect the animal and send a signal to the Pic. Which will then activate the pump for a few seconds. The pesticide will then be pumped into the tube and come out of the small hole of the tube.


Simple construction.

Animals would not have to be rounded up.

Would not scare the animals.


The battery will discharge after a certain time period.

Cannot handle a large number of animals at once.

Some of the poison will be wasted.

Concept 2:





Figure 14

1 Spring.

2 Pole

3 Absorbent material.

4 Slider.


This system will be placed at a gate where cattle must past through. The absorbent material will be dipped in pesticide and wrapped around the pole. As the cattle walks through the system the poles will be pushed away from each other by the cattle. But the spring on top of the system will keep pulling the poles back together.


This system can treat a lot of cattle.

The absorbent material does not have to be replaced often.

Very cost effective system.


The system only works if the cattle passes through it

The spring will wear after a certain time.

Concept 3:








Figure 15 Figure 16


Swivel plate



Spray nozzle

Support plate

The side from which the cattle should enter the system.


This system must be placed at a gate where cattle pass through. As the cattle passes between the two poles they move the swivel plate. The swivel plate compresses the piston which causes pressure in the tank. The tank gets rid of the pressure by spraying pesticide out of the nozzle.


Can treat a lot of cattle with very little effort.


The cattle must past through the system to work.

The cattle needs to be rounded up.

If the animal is very small it will walk through the system without being treated



Concept 4:


Figure 17




Figure 18



Spray nozzle.

Box containing the battery, tank, pump and circuit board.

Mounting plate.

Solar panel.


If the animal walks between the two sensors a signal is sent to the Pic. The Pic activates the pump which sprays the pesticide from the nozzle

This system can be implemented at various location. I have added brackets so that is can be hang from a fence or pole.


The battery will never discharge completely because it is connected to a solar panel.

This system can be used on cattle or game of different sizes.

It can be implemented in walkways or traditional cattle press passages .

No spillage or waste of pesticide.

Fully adaptable for all types of conditions

Disadvantages :

The system can be costly.

Concept selected:

The concept selected was number 4. It is very diverse. It can be used on a cattle farm for a large number of cattle, or even on a game farm for spraying game while they gorge at a certain area.

The Table below gives a summary of the equipment and methods chosen.

Options chosen are highlighted .



General group options

Solar power

Solar panel

Concentrated solar power

Thermo generator



Lead acid

Sealed lead acid

Controlling the system



Pic program used


LD micro

Mp Lab

Spraying of pesticide







Demand CS Insecticide

Dragnet SFR


Table 1

Design discussion:




Figure 19 Figure 20

Component 1: Solar panel

Figure 21

A solar panel is used to charge the battery. The solar panel delivers roundabout 14.5W at 12-14Volts. Placing of the solar panel is very important for maximum efficiency. When in the Southern hemisphere the panel should face north, and when in the northern hemisphere the panel should face south. Best angle for the solar panel is at the same angle as your latitude. This system is designed to operate efficiently in Brits (North west province). The angle used is 25o.

Component 2 : Solar panel bracket.

Manufacturing process:

Material 2mm sheet metal

Laser cutting of sheet metal.

Bending sheet metal according to drawing.

Welding of corners

Surface treatment: Powder coating.

The solar panel is fastened to the bracket via 4 pop rivets (3/44)

Component 3: Pole

The pole is welded to the solar panel bracket





Figure 23

Figure 22

Component 4: Spray nozzle

The nozzle used is the Axialflow Full cone nozzle. It has an uniform liquid distribution over the whole circular impact area. The spray angle can be adjusted as well as the flow rate.

Component 5 : Clamp

This clamp comes in standard sizes and can be bought from Builders Warehouse.

Component 6 : Shrink fitting

It is used to connect the pipe with the nozzle. A crimping tool will be used.






Figure 24

Component 7: External box

Manufacturing process:

Material 1.5mm sheet metal

Laser cutting of sheet metal.

Bending sheet metal according to drawing.

Welding of corners

Surface treatment: Powder coating

The external box will house all the various components such as the battery, circuit board, tank, pump and the regulator.

Component 8: Mounting plate

Manufacturing process:

Material 1.5mm sheet metal

Laser cutting of sheet metal.

Bending sheet metal according to drawing.

Welding of corners

Surface treatment Powder coating

The purpose of the mounting plate is for the screws not to stick out of the external box. The mounting plate is welded to the external box.

Component 9: Pesticide box

Manufacturing process:Material 1.5mm sheet metal

Laser cutting of sheet metal.

Bending sheet metal according to drawing.

Welding of corners

Surface treatment Powder coating

Purpose of this box is to carry the Tank which contains the pesticide and the small pump. The pesticide box is welded to the mounting plate.

Component 10: Battery box

Manufacturing process:

Material 1.5 mm sheet metal

Laser cutting of sheet metal.

Bending sheet metal according to drawing.

Welding of corners

Surface treatment Powder coating

The purpose of the Battery box is to house the battery.

Component 11: Hook

Purchased from Builders Warehouse X 4

Bolted to external box and plate 2 with 8mm bolts grade 4.6









Figure 25

Component 12: Door

Manufacturing process:

Material 1.5mm sheet metal

Laser cutting of sheet metal.

Surface treatment Powder coating.

Component 13: Bullet 1

Manufacturing process:

Material 5mm rod

Drilling of hole 3mm in diameter

Surface treatment electroplating

These 2 bullets are welded to the external box.

Component 14: Bullet 2

Manufacturing process:

Material 5mm rod

The step is cut by making use of turn table.

Surface treatment electroplating.

The bullet acts like hinges the bullet is welded to the door

Component 15: Locking mechanism

This component can be bought at Builders Warehouse. They are pop rivited to the door and external box as shown. By (3/44) size rivets.








Figure 26

Component 16: Tank and with it the pump.

Can be bought from Toyota garage.

Component 17: Circuit board

Controls the system with various components. Of which the main component is the Pic. The pic used for this system is the PIC16F88. This is a very powerful pic. It is important that this pic is used because it can receive analogue values. The pic is programmed using the program LD micro. The sensor is connected to the pic as an input. And the battery voltage level is also connected to the pic. When the battery voltage level drops below 11.5V the entire system will switch off. Can be bought at Communica for R50.[See figure 26]

Figure 27

Component 18: Regulator.

Figure 28

The Regulator used is a BAT 101. It regulates the voltage which comes from the solar panel so that the battery does not overcharge. The regulator takes the voltage from the solar panel which is about 14 volts and charges the 12 volt battery The amount of power this regulator can handle is 50 W. Can be bought at Communica for R125.[See figure 27]

Component 19: Battery

A normal 12Volt acid battery is used to power up the entire system.

Component 20 : Sensors

Figure 29

Infrared sensors are used which is normal gate sensors which work from a 12 volt battery. The sensors can work at a distance of up to 30 meters When the sensor senses movement it activates an internal relay which switches 5v. The 5V signal is sent to the Pic. Can be bought at Communica for R140.[See figure 28]

Component 21: Plate 2

Manufacturing process:

Material 1.5 mm sheet metal

Laser cutting of sheet metal.

Surface treatment Powder coating


Calculating of voltage divider rule:

Figure 30

V out = (R2/(R1 + R2)) X Vin

R1 = 3300 Ω

R2 = 1000 Ω

V in = 12 V

V out can be calculated by using the following formula.

V out = [R2/(R1 + R2)] X Vin

V out = [1000/(3300 + 1000)] x 12

= 2.791 V

The amount of current the voltage divider rule is taking from the battery:

V = I x R

12 = I X (3300 + 1000)

I = 12/4300

I = 2.8 mA

The amount of Current the solar panel can supply:

The solar panel delivers 14W of power at 12 volts.

P = V x I

14 = 12 x I

I = 1.167 Ah

There is 6 hours a day for the solar panel to charge the battery thus the current must be multiplied by 6

I = 1.167 X 6

= 7 Ah day charge

The average amount of current the pump takes is 3.5A

The battery specifications indicate that it can deliver 7Ah. But this would destroy the battery. For an acid battery only 15% of its Amps an hour can be used.

I = 7Ah X 15%

I = 1.05Ah

If the pump would spray for 3 second and sprays 350 cattle, the daily energy consumption would be the following.

3(seconds) X 3.5A(the amount of current the pump takes) X 350(number of cattle)

I = 3675As

I= 1.02Ah

Solar panel supplies the battery with I = 1.167 Ah

The battery can supply I = 1.05Ah

The pump uses I= 1.02Ah

This calculation proves that the solar panel could charge the battery efficiently. And the battery could operate for an entire day before it needs to be charged.

Calculating of Average shear stress and bearing stress between the bolts of the hook and the weight of the external box and its components:

The mass of the materials was obtained making use of solid works. The time of material for the sheet metal is steel AISI 304.

Mass of external box = 4842.735 grams.

Mass of mounting plate= 1485.525 grams.

Mass of door = 1675.927 grams.

Mass of pesticide box = 428.58 grams.

Mass of battery box = 159.59 grams.

Mass of tank filled with pesticide = 5500 grams.

Mass of battery = 3650 grams

Total mass = 17742.357 grams which is the same as 17.74 Kg.

Average shear stress:

17.74 X 9.81 = 174.03 N

σ bolt = F /A

= (Force)/(number of bolts)(area of bolt)

σ = 174.03/ (4)( π)(0.004)2

= 0.86555 Mpa

Safety factor:

sf = (400X0.577)/(0.86555)

= 267

Bearing stress :

σ = F /A

Force/(number of bolts)(diameter of bolts)(thickness of material)

= (174.03)/(4)(0.008)(0.0015)

= 3.625 Mpa


By building a small model and according to the calculations that has been done this system is possible to build and operate very efficiently. Though the pump is a bit noisy it would work great for cattle, but may cause game to be frightened. I think this is not a major problem for the game will get use to the sound of the pump. This design will save pesticide that will ultimately lead to moneysaving. This project has been successful ,and can truly be build and used on cattle farms and game farms.

Several programs was used for this project

Solid works

Ld micro

Smart draw vp