We are a 5th year Electrical and Computer Engineering students undersigned, declare that this project is our original work and has not been presented for a degree in any form and in any other university and that to the best of our knowledge and belief all source of material used for the project have been duly acknowledged.
1. __________________________________ _______________________
2. __________________________________ _______________________
3. __________________________________ _______________________
4. __________________________________ _______________________
5. __________________________________ _______________________
Approval of Advisor
As the student advisor, I clarify that this final year project which prepared by the students listed above is original work and complained according to the guideline provided by the department as far as my knowledge is concerned.
Confirmed by Advisor:
First of all, we would like to thank the almighty God for the base of all the successful progress of life as a whole and this project as a particular. We would like to offer our deepest gratitude to our advisor Dr. Amruzh who shared with us the main principles of a successful preparation for a final project, who had the main role of providing us with the components of the project, and reviewing the context of this project with us. We extend our sincere thanks to Mr. Mengistu F. for his advice, support and guidance through the entire project.
Finally, we also extend our sincere thanks to all other faculty members of Electrical and Computer Engineering department and our friends for their support and encouragement.
With the increasing of Ethiopian population day to day the focus on effective and agricultural methods are getting more attention. To satisfy the need of those population we must develop and follow modern agricultural technology. Not only those but also, according to survey conducted by WHO (World Health Organization) it is estimated that every year about 3 million workers are affected by poisoning from pesticides from which 18000 die. In addition to these, there are many people that are suffering for venomous snakes and insects that can be occurred regularly in farm field. Thus with this as a major area of concern, this project deals with the development of remote controlled smart pesticide and fertilizer spraying hexacopter drone to help farmers. The proposed drone should be able to spray insecticides, pesticides and fertilizers using a tank provided onto the frame of the drone.
The process of spraying fertilizer, pesticide and manure spreading technique is done by using android application device. Here the hexacopter can be control through android phone for fertilizer and pesticide spraying process. So the hard work, human efforts, number of human labors can be reducing by it. This system reduce the problem related to the agricultural field and increase the agricultural productivity and also reduce the health problems which are caused by manual spraying.
Table of content
List of Figures
List of Tables
BLDC Brushless DC motor
CCW Counter Clockwise
DC Direct Current
ESC Electronic Speed Controller
FCB Flight Controller Board
IMU Inertial Measurement Unit
I2C Inter-Integrated Circuit
LiPo Lithium Polymer
PDB Power Distribution Board
PID Proportional Integral Derivational
PVC Poly Vinyl Chloride
PWM Pulse Width Modulation
RC Remote Control
RF Radio Frequency
RPM Revolution Per Minute
RPV Remotely Piloted Vehicle
SCL Serial Clock Line
SDA Serial Data Line
UAV Unmanned Arial Vehicle
WHO World Health Organization
WI-FI Wireless Fidelity
It is known that the main source of Ethiopian economy is agriculture. More than 80 percent of the population of the country are farmers whose income is depend on mainly agriculture. Even if so, today there are many people which are suffering for hunger due to shortage of food which is the result of traditional agricultural practice throughout the country. Now days the government of Ethiopia start to import agricultural products from foreign countries to solve this problem. However, this may not be the exact solution of the problem. As we know, the population of Ethiopia is increasing day to day. With the increasing of population day to day the focus on effective and modern agricultural methods are must get more attention, but it still uses obsolete methods.
The application of pesticides and fertilizers play a vital role for modernization of agricultural sector and gives higher crop yields. The rate of agriculture production is affected by major biological factors such as pests, diseases, weeds etc. These biological factors can be controlled by human beings with the help of pesticides and fertilizers, which ultimately increasing the productivity. All most all farmers in the country uses labor force to spray those pesticides and fertilizers to their farm in traditional way. Conventionally the spraying is done by labors carrying backpack sprayer and fertilizers are sprayed manually. During this time, pesticide exposure affects the human health in various ways and causes neurological and skin diseases like asthma, allergies, hypersensitivity, cancer, hormone disruption, and problems with reproduction and fatal development. According to survey conducted by WHO (World Health Organization) it is estimated that every year about 3 million workers are affected by poisoning from pesticides from which 18000 die. In addition to these, there are many people that are suffering for venomous snakes and insects that can be occurred regularly in farm field.
To overcome all these ill effects of the pesticides and fertilizers on human beings and also used to spray pesticides over large areas in short interval of time compared to conventional spraying, we are going to design and implement an automated aerial pesticide sprayer, so as to increase crop productivity throughout the country.
The hexacopter drone that we are going implement will be helpful in spraying fertilizers, pesticides and crop protection products while being controlled by a single person operating from a safe area at the ground. By changing the type of container used, the device can be used for spraying fertilizers, pesticides and crop protection products like manure etc. There by greatly reducing the time taken and maintaining the safety precautions for the farmer while spraying fertilizers and pesticides.
The device that we are going to implement is a combination of spraying mechanism on a hexacopter frame. The process of spraying the pesticides and fertilizer is controlled by means of a remote and android application. The information is fed through remote and android application that controls the functioning of valve to prevent the loss of pesticides and fertilizers. The body of the hexacopter aerial drone is mainly made of wood frame designed large enough for the use of propellers with a pesticide tank underneath with a capacity of 0.5 liter and a sprayer for spraying the pesticides effectively on an agricultural field and it also have a space for fertilizer storage. It is then mounted onto a hexagonal body with a brushless motor at the end of each arm that carries propeller made of composites of carbon nylon and other additives.
1.2 Statement of Problem
The World Health Organization estimates that there are around 3 million cases of pesticide poison in each year and up to 220,000 deaths, primarily in developing countries. Organophosphates and carbonates, affect the nervous system. Others may irritate the skin or eyes. Some pesticides maybe carcinogens others may affect the hormone or endocrine system in the body. Even very low levels of exposure during development may have adverse health effects. Pesticide exposure can cause a range of neurological health effects such as memory loss, loss of coordination, reduced speed of response to stimuli, reduced visual ability, altered or uncontrollable mood and general behavior, and reduced motor skills and to cover larger areas of fields while spraying pesticides in a short span of time when compared to a manual sprayer.
On the other hand, it is known that agriculture is the backbone of our country. Even if that, the Ethiopian agricultural sector still uses traditional methods. Pesticides and fertilizers play a vital role for increasing agricultural products in quality and quantity. This project is to mainly overcome the ill effects of pesticides on human beings (manual pesticide sprayers) and used to increase agricultural products in quantity and quality by spray pesticide and fertilizer over large areas in short interval of time compared to conventional spraying by using an automated system.
1.3.1 Main Objective
In this project, our major objective is to change the obsolete methods being currently followed in Ethiopian agriculture systems by helping the farmers to spray the pesticides or fertilizers on crops using hexacopter drone system and to reduce the ill effects of the pesticides and fertilizers on human beings.
In addition to our main objective, we have done the following specific tasks and each of them plays a vital role for the final system that we are going to design and implement.
To design a mechanism for pesticide and fertilizer spraying tank
To assemble the hexacopter drone using necessary components
To control different parameters like spraying speed and the drone speed control
Interfacing ESC with Arduino UNO
1.4 Scope of the Project
The scope of this project covers design and implementation of the hexacopter drone for pesticides and fertilizers spray that requires less maintenance with low cost for Ethiopian farmers. There are two parts involved this project, namely the hardware and software. The hardware part involved the construction of the water turbine, preparing the appropriate tank for the pesticides and fertilizers, assembling different parts of the hexacopter drone and controlling the flight using remote controller. In the software part each sensor has its own background thread that constantly reads and updates incoming data, whilst monitoring for errors and logging. Android application also developed to control the spray of pesticide and fertilizer through our smart phone.
1.5 Expected Outcome
From this project, we will expect that the final hexacopter drone and design of sprayer had to meet the following specifications after the completion of the project:
The drone must be capable of flying and landing in stable manner.
The pesticide and fertilizer spraying process must be done perfectly.
Synchronization of hexacopter and spraying system should be done without any imperfection.
The flight controller that we are design must control the drone as the required direction.
1.6 Project Outline
The thesis out line of hexacopter drone for pesticides and fertilizers sprayer project contains six chapters. The first chapter starts with brief introduction of the project. This chapter describes the background of the project, the problem statement, objectives and the scope of the project. The second chapter is about the researches related to fields of the project that are mainly about the UAV system. Chapter 3 discusses the methodology of the project that includes programming of Arduino UNO using arduino software, the characteristics of different sensors and the overall construction of the hexacopter drone. Chapter 4 presents the system design and implementation of the project and some discussions. Chapter 5 deals about simulation result and discussion of the result. Finally, Chapter 6 will be conclusion, recommendation and future work. It will conclude the whole project and enhance or recommend some future works for the project.
This chapter describes the past and current researches that have been carried out that are related to this project. This survey investigates numerous aspects of sensors and the overall working system of the related projects.
The advent of UAV system as aerial sprayers has been recent and its adoption commercially is still limited. UAV system include both autonomous (means they can do it alone) drones and remotely piloted vehicles (RPVs). Japan’s Yamaha Corporation was the first to produce an unmanned aerial vehicle for spraying crop protection product 8.
2.1 Unmanned Aerial Vehicles (UAV)
An unmanned aerial vehicle (UAV), commonly known as a drone, as an unmanned aircraft system (UAS), or by several other names, is an aircraft without a human pilot aboard. The flight of UAVs may operate with various degrees of autonomy, either under remote control by a human operator, or fully or intermittently autonomously, by onboard computers.
Compared to manned aircraft, UAVs are often preferred for missions that are too dull, dirty or dangerous for humans. They originated mostly in military applications, although their use is expanding in commercial, scientific, recreational, agricultural, and other applications, such as policing and surveillance, aerial photography, agriculture and drone racing. Civilian drones now vastly outnumber military drones, with estimates of over a million sold by 2015 5. Originally developed for military purposes (Graham, 2010), drones now have manifold civil applications and can be flown with little to no training. This development has gained great momentum especially since the start of the 21st century (Rothstein, 2015) 4.
Multiple terms are used for unmanned aerial vehicles, which generally refer to the same concept. The term drone, more widely used by the public, was coined in reference to the resemblance of navigation and loud and regular motor sounds of old military unmanned aircraft to the male bee. The term has encountered strong opposition from aviation professionals and government regulators 2.
2.2 Types of Unmanned Aerial Vehicles
There is no one standard when it comes to the classification of UAV. Defense agencies have their own standard, and civilians have their ever-evolving loose categories for UAV. People classify them by size, range and endurance, and use a tier system that is employed by the military. For classification, according to size, one can come up to classify as multi rotor, fixed wing and single rotor 1.
2.3 Hexacopter Drone Configuration
The hexacopter has six motors mounted typically 60 degrees apart on a symmetric frame, with three sets of CW and CCW motors or propellers. Hexacopter are very similar to the quadcopters, but they provide more lifting capacity with the extra motors. There is also improvement in redundancy. If one motor fails, the aircraft can remain stable enough for a safe landing. The downside is that they tend to be larger and more expensive to build. The configuration of the hexacopter is shown in Figure 2.1 below.
Fig 2.1 Hexacopter configuration
2.4 Basic Components of Hexacopter Drone
The hexacopter is the result of different components such as frame, flight controller, transmitter and receiver, batteries, propellers, motors and ESCs that are assembled together to form the complete system. The frame or body is what holds everything together. It is designed to be strong, light weight, and consist of a center plate where the main flight controller chip and sensors are mounted and arms where the motors are mounted.
The BLDC motors are responsible for to turn the propellers, which is responsible for providing thrust for countering gravity and drag. Every rotor ought to be controlled separately by a speed controller. Motors are the primary force behind how hexacopter fly.
The electronic speed controller or (ESC) is a device that tells the motor how to spin. It is responsible for controlling the rate at which the motor spins the propeller.
The flight controller is the brain of the hexacopter. It sits at the center, controlling the firmware within the ESCs, consequently controlling the spin rate of the motors.
Lithium polymer (LiPo) batteries are the most famous power source for controlling drones today. Without going a lot into detail, the principle explanation behind this is because they are rechargeable and ordinarily have expansive limits.
A hexacopter has six propellers, three normal propellers that spin counter-clockwise, and the remaining three are pusher propellers that spin clockwise.
2.5 Working Principle of Hexacopter Drone
Hexacopter have five main components; the power supply, speed controller, the motors, the flight controller and power distribution board. All of these components are place on a hexacopter frame that places the six motors at equal distance with propellers 6.
The flight controller unit is the brain of the entire unit and it controls every function of the system. It also contains additional sensors to help flight stability.
The electronic speed controller (ESC) orders the motors how they need to spin. It may give simple sound but the ESCs are the most important components in the system. Each motor has to spin at variable speeds to ensure proper flight and handling.
The remaining components such as battery, motors, and power distribution board have their own applications. The battery provides the power, the power distribution board sends the power where it is needed and when it is needed, and the motors spin the propellers as directed.
2.6 Pesticide Spraying Methods
There are different methods of pesticide spraying techniques that are practiced today in all over the world. Among these methods backpack sprayer, Lite-Trac sprayer, Bullet Santi sprayer and the recently discovered aerial sprayer are available to increase agricultural products in quality and quantity and also to minimize human power. These sprayers also the minimize the time that required to spray agricultural field and gives more productivity in less input. Even if modern spryer techniques are available, Ethiopian farmers didn’t use them still due to the high cost of the technology.
Backpack sprayer: It is mostly a plastic made container which operates on the principle of compressed air with harness that allows it to carried on the operator’s back. There is hand operated hydraulic pump that forces liquid pesticide through a hose and one or more nozzles. After we determine the amount of mixture needed and proper amount of water to the tank for our application, the labor has to carry all the weight of the pesticides filled tank which causes fatigue to labor and hence reduces the human capacity. This sprayer is adopted throughout Ethiopian farmers due to its low price 7.
Fig 2.3 Backpack sprayer
Lite-Trac is a trading name of Holme Farm Supplies Ltd, a manufacturer of agricultural machinery registered in England and based in Peterborough. The Lite-Trac name comes from “lite tractor”, due to the patented chassis design enabling the inherently very heavy machines manufactured by the company to have a light footprint for minimum soil compaction. The company’s products are identifiable by the combination of unpainted stainless steel tanks and booms with bright yellow cabs and detailing. A Lite-Trac crop sprayer, or liquid fertilizer applicator, mounts onto the SS2400 Tool Carrier centrally between both axles to maintain equal weight distribution on all four wheels and a low center of gravity whether empty or full. The stainless steel tanks are manufactured in capacities of up to 8,000 liters, whilst Pommieraluminium booms of up to 48 meters can be fitted 7.
Aerial Sprayer: Aerial sprayer is another type of spraying; it is beneficial for the farmers having large farms. This technique is not affordable by farmers having small and medium farm. It is modern technique in agricultural field. In aerial spraying the spraying is done with the help of small helicopter controlled by remote. On that sprayer is attached having multiple nozzles and sprayed it on the farm from some altitude. It is less time consuming and less human effort required to spray fertilizers 7.
In this chapter the block diagram representation of the hexacopter drone and its brief description, flow chart diagram of the system and its algorithms will be discussed. In addition to these, the spraying mechanism for both pesticides and fertilizers will be presented.
3.1 Block Diagram of Hexacopter Drone for Pesticide and Fertilizer Spraying
The overall block diagram of the system is given as shown in Figure 3.1 below.
Fig 3.1 Block diagram of hexacopter drone for pesticide and fertilizer spray
The figure 3.1 above demonstrates the block diagram of the overall system. The system energized from a rechargeable battery called LiPo cell. Lithium Polymer cells (LiPo) are a tremendous advance in battery technology for RC use only. The power distribution board (PDB) distributes power from the LiPo that runs to the other components of the drone. The six ESCs orders the six motors how they need to rotate. The system has six BLDC motors that functions to rotate the propellers. The flight control board (FCB) is the brain of the hexacopter which contains different sensors that determines how each of the hexacopter’s motors spin.
3.2 The Components Used in the Project
In this project we are use the following main components.
1.Frame with Integrated PCB
3.Arduino UNO Board
4.1000KV Brushless DC Motor
5. 30A ESC (Electronic Speed Controllers)
6. 11.1V 2200mAh 35C Lithium Polymer Battery
The body or the frame of the drone is the component that carries everything together. It is design from strong and lightweight materials to avoid the side effect on the flight process. The frame consists of a center plate where the main flight controller chip and sensors with BLDC motors are mounted. It is mostly made of carbon fiber, fiberglass, aluminum or steel. Some cheaper, smaller models also use plastic. In our project, the body frame of the hexacopter drone is design from lightwood that are easily available in our surrounding to minimize the overall cost of the project.
We use hexacopter propeller Kit is intended to be used with hexacopters. The propeller adapters fit all thin electric propellers with diameters of 8 inch. We use six propellers, 3 of them rotates in clockwise and the rest rotates counter clockwise direction.Those propellers are made from durable plastic. The specifications of the propellers are:
• Thickness: 0.36 inch.
• Shaft diameter: 0.25inch.
• Propeller weight: 0.78 Oz (ounce) or 0.022Kg.
The propellers that we are used are shown on Figure 3.2 below.
Fig 3.2 Propellers
3.2.3 LiPo Batteries
Lithium polymer batteries, more commonly known as LiPo, have high energy density, high discharge rate and lightweight, which make them a great candidate for hexacopter applications. LiPo batteries used in RC are made up of individual cells connected in series and we use 3S LiPo. Each cell has a nominal voltage of 3.7V and a total voltage of 11.1V. The LiPo battery voltage affects BLDC motors RPM directly, therefore we can use higher cell count batteries to increase the hexacopter speed if the motor or ESC and other electronics support higher voltage.
LiPo battery is designed to operate within a safe voltage range, from 3.2V to 4.2V. Discharging below 3V could cause irreversible performance lost and even damage to the battery. Over charging above 4.2V per cell could be dangerous and eventually cause fire. Increasing the battery capacity gives longer flight time, but it will also get heavier in weight and larger in physical size. There is a trade-off between capacity and weight that affects flight time and agility of the hexacopter.
Battery Calculations: We must know and calculate the amount of energy that the battery consuming; hence the source required by the battery is;
Max source = discharge rate × capacity; the battery has a capacity of 2200 mAh and discharging rate of 25C. Therefore;
Max source= 25×2200mAh=55000mAh=55Amp; So, the max source i.e. ESCs should not exceed 55A, since we have selected a 30A ESC there is no problem, it is perfect battery. We should never discharge a Li-Po battery below 80% of its capacity.
Watt calculation of 3S LiPo:
Watt = V(Voltage) × I (Ampere),but; I (Ampere) = (Max Efficiency) × (Max Current); 0.8×20A=16A
Watt of LiPo=11.1V×16A=177.6Watt, The actual LiPo battery is shown on Figure 3.3 below.
Fig 3.3 LiPo battery
3.2.4 BLDC motors
A brushless DC motor is a permanent magnet synchronous electric motor which is driven by direct current (DC) electricity and it accomplishes electronically controlled commutation system (commutation is the process of producing rotational torque in the motor by changing phase currents through it at appropriate times) instead of a mechanically commutation system .These motors are the primary force behind how hexacopter fly and they are like typical DC motors in the sense that coils and magnets are utilized to drive the shaft. The brushless motors do not have a brush on the shaft that deals with iterating the power in the coils, hence, the name “brushless” is used to call them. These motors have the responsibility of turning or rotating the six propellers as we order them through program instructions. A speed controller controls every rotor of the motor separately. This motors have 3 coils inside the center of the motor, which is settled to the mounting. On the external side, it contains multiple magnets mounted to the cylindrical structure that is appended to the turning shaft. Since the coils are fixed, there is no need for brushless. The actual physical diagram of the BLDC motor is shown on Figure 3.4 below.
Fig 3.4 BLDC motor
Construction of BLDC motor
BLDC motors can be constructed in different physical configurations. Depending on the stator windings, these can be configured as single-phase, two-phase, or three-phase motors. However, in our project we use three-phase BLDC motors with permanent magnet rotor are used. The construction of this motor is similar to three phase induction motor as well as conventional DC motor. This motor has stator and rotor parts as like all other motors.
The Stator of a BLDC motor made up of steel laminations to carry the windings. The windings are placed in slots which are axially cut along the inner periphery of the stator. These windings can be arranged in either star or delta. However, most BLDC motors that we are used in the project have three phase star connected stator.
The rotor of BLDC motor incorporates a permanent magnet. The number of poles in the rotor can vary from 2 to 8 pole pairs with alternate south and north poles depending on the application requirement. In order to achieve maximum torque in the motor, the flux density of the material should be high. A proper magnetic material for the rotor is needed to produce required magnetic field density.
Operation of BLDC motor
BLDC motor works on the principle similar to that of a conventional DC motor, that is on the Lorentz force law which states that whenever a current carrying conductor placed in a magnetic field it experiences a force. As a consequence of reaction force, the magnet will experience an equal and opposite force. In case BLDC motor, the current carrying conductor is stationary while the permanent magnet moves. When the stator coils are electrically switched by a supply source, it becomes electromagnet and starts producing the uniform field in the air gap. Though the source of supply is DC, switching makes to generate an AC voltage waveform with trapezoidal shape. Due to the force of interaction between electromagnet stator and permanent magnet rotor, the rotor continues to rotate.
It is known that the whole power system depends on selection of motor. So this project used Brushless DC motors its specifications are described below on Table 3.1.
Table 3.1 BLDC motor specification
Max Current 20A
Max Efficiency 75%
NO load current at 10V 0.75A
3.2.5 Flight Controller
The flight controller is the brain of the hexacopter drone. This board is what sits at the center, controlling the firmware within the ESCs, consequently controlling the spin rate of the motors. It mainly controls the rotation of the six ESCs and the gyro sensor. It takes the inputs from the receiver and adjusts the motor RPM accordingly, via ESC. In our project the flight controller is designed by using MATLAB Simulink and arduino UNO incorporated with gyro sensor.
3.2.6 Electronic speed controller
ESC stands for Electronic Speed Controller which is used to vary the speed, direction and possible to act as a dynamic brake, of a Brushless Motor. It converts the PWM signal from the flight controller or radio receiver, and drives the brushless motor by providing the appropriate level of electrical power. Most modern ESCs switch at a much higher rate, which makes them much more efficient by lose less power as heat in the controller. The maximum current usage of an ESC needs to be greater than the motor and propeller combination will draw. In terms of ESC, suggesting 20%-50% extra Amps is good to prevent the ESC from burnout. The ampere rating of BLDC motor is 26A so we considering the current rating of the ESC will be:
ESC amp rating = 1.2 to1.5 x max amp rating of motor
=1.2 to 1.5 x 20A=24A to 30A, therefore we can select the amp rating of ESC between ranges of 24A to 30A. Due to this, we have chosen the ESC of 30A. The hexacopter has six motors and its respective ESC, so all six ESCs will draw a total current of: 6*30A=180A.
Fig 3.5 Electronic speed controller
3.2.7 RC transmitter and receiver
The transmitter is the radio controller FS-i6X and the receiver is FS-IA6 with a six channel 2.4GHZ AFHDS 2A digital proportional RC system. The 1st four channels are generally used for flight controls and the last two are for other operations. It is used to control the hexacopter by sending reference values for roll, pitch, yaw and throttle. The operator can then control the hexacopter through its control system. The receiver must be connected to the flight controller, which needs to be programmed to receive RC signals.
FS-i6 Transmitter Specifications: The following table 3.2 bellow describes the specifications of the remote transmitter.
Table 3.2 specifications of the RC transmitter
No of Channels 6
RF Range 2.4-2.48GHZ
Low Voltage Warning