The Main Methods Used in Robotics Creation - Essay Example

Download file to see previous pages This project focuses upon robotics creation to be used in the several ways that can benefit humanity, such as being used in complex operations, fast routines operations, which is needed for better accuracy, narrow sites, and dangerous fields such as contaminated sites that a human cannot enter. In this report I will explain the method of making a robot that has the ability to move in different directions through wireless communication. In addition to constructing the program, which has the ability to control the robot through the PC, to complete the process of making the robot, there are several key components that need to be used that will be explained in the report in more detail. The main methods used in the robotics project are the laboratory experiments on the several works to make sure that all of the components are working to serve the robot.

This has been done by testing and examining the different systems, such as serial communication interface, wireless communication, wires connections, power, et cetera. Through the recorded observations and written tests, results are made on the robot project requirements to help make the project more understandable. The main conclusion of this project is that all of the robots work through the three main components, which are robot bodies, software, and processors. In addition, there are some components that may help in other operations, such as the robot camera, which is used to monitor, and sensors that are used to sense, et cetera.

Acknowledgements.

I would like to give thanks to all who have contributed in my study field by supporting me financially and morally, and encouraging me to persevere in the study to make an effort to show a good final year project quality. First off, I would like to give special thanks to my mother, who raised me on a spirit of determination and challenge to confront the difficulties of study and the removal of all obstacles through its direct support to all of my study requirements. Secondly, special thanks to Mr. Panos Abatis, my final year project supervisor, who did not hesitate days in creating a guideline to show the project in good quality, and I offering him a salute to listening to all of my questions and responding to them adequately, as well as following-up the project with him step by step. Special thanks also goes to Mr. Alex, who has helped me in the project design and has provided me with all of my requests of the robot design tools. Also, I would like to thank the University of Coventry, who gave me the opportunity through the provision of academic disciplines, as well as the university for its support of students wishing to create their projects through the facilitation of all things and providing a large number of projects in several disciplines. 1 Introduction. Robotics has become a necessity to facilitate our daily lives, as the use of these robots in various fields has become very common. We have to look and aim to develop their use to become more easier and perform more accurately.

Thus, I decided to choose the final year project in the developing of the robot’s performance. 1.1 Background of the Project. Through continuing research and studying, we can find solutions to problems or analyze these problems in order to create easy solutions. However, first we must understand the problem and then begin thinking about the solution method. Then we can apply these solutions through laboratory experiments to test the results to see if they are satisfactory or unsatisfactory. The problem here is how to create a wireless robot that can receive instructions from the computer and move in different directions, as well as to use wireless cameras fitted on the top of the robot to transmit live video to the computer screen. This work needs in-depth information in computing and electronics, through research in books, the Internet, and articles, keeping track of all that is new in the field of robotics, and by means of going back through first and second year lecture notes and lab experiments. I understand that the problem involves more accuracy, and therefore I have imagined the solutions; in fact there was some difficulties I faced during implementation, but I was able to pass many of them to make the project useful and easy to implement. There are many who can benefit from this project, for example, programmers, computer engineers that are interested in the field of wireless communications, robotics developers, security monitors and those who have special needs.

1.2 Project Objectives.

There are several objectives of this project. My first priority of these objectives is to increase the technical and professional skills in robotics. In addition, I want to test the ability to transform ideas into concrete projects, as I think that this will help to create a spirit of creativity and innovation, which may help to develop the robots for better performance. Another objective is to serve those who are interested in robotics through the delivery of useful information to all who are interested in software development, wireless communication, computer engineering, et cetera. By explaining how to create a robot, through this detailed explanation, the reader will be able to create a similar project, if the all project requirements are available.

The report will contain several definitions and geometric terms of each part of the robot that was used in the project, as there are some parts that are used but they will not be included in the report. There are also some parts that are not in use but will be included in the report because they are not necessary in the completion of the project, which is based on the project requirements. There is also an explanation of the program code that has been used to control the robot, as well as some details about the design of the robot body. One of the more important objectives of this project is to write the report in academic writing, as this may facilitate the method of explanation for the reader to be able to understand the ideas, and by simplifying the writing and making it easy to understand, which may lead to the accuracy in the performance.

1.3 Overview of This Report.

At the begin of chapter two, I will discuss the reason of why I chose this type of project, as well as detailing what the positive aspects are, which can be exploited by working on this project, then how to understand the project and discuss the project resources and alternatives. In chapter three, I will explain the methodology of the drive by the wire robotic vehicle project and I will focus on the reason of my choosing this project, as this project will help my future study, and what the relationship between this project and my course and if the project is considered typical. In chapter four, what will be discussed is the actual work, followed by a discussion as to what the requirements were that helped to complete the project, in addition to detailed explanations through pictures and comments.

The fifth chapter will identify the relationship between the robot components by using diagrams with comments to allow for a clearer explanation. In the sixth chapter, I will show the steps on how to make the robot body and how to make the PSB circuit board for the wireless device. Chapter seven focuses on the implementation of the work involved with laboratory experiments. Chapter eight is related to the technical testing, where some of the components needed to be tested before fitting them on the actual robot. In chapter nine, I will show the quality management of some of the components. Chapter ten involves the critical appraisal of the overall project. Chapter eleven will discuss the project conclusions and what has been done, as well as what is the future work.

Chapter twelve focuses on the reflection or what were the problems that were faced and how they were solved, in addition to the lesson that was learned. Finally, at the end of this report I will reference all of the sources that been used to make this project, in accordance to CU Harvard style. 2 Project discussion and general information. In the beginning, the project was unclear, and I was fearful of the possible inability to complete all of the project stages, but I decided to do my best to complete it and show it in good quality. The first step was to make the project clear. I met with my project supervisor and discussed with him the project requirements in technical depth; he advised me to go back into my first and second year experiments to refresh my memory and to get some general information on electronics and computing, because these would help me to be ready to start the project lifecycle.

2.1 Understand the project. With the continuous search on the Internet and by focusing on the robotics by reading robotic books, articles and following robotics-related news to know how to make robots or how to control them, I found that there are a large number of people who are discussed within this topic. I am interested in being one of those who is learning, eventually becoming an expert in this area; therefore, I have got good ideas about how to start making the robot, and what the main requirements are to make a robot, in addition to trying to collect a large number of information will help to enrich the report writing. 2.2 Discuss the project resources. Before starting the project, I must identify the actual project resources; to implement any project, it needs to have its appropriate resources. I believe that my project was in need of some resources to be able to complete it. These resources consist of human, equipments, materials, places and time sources.

2.2.1 Human resources: I. The student who will live with the project day to day. II. The supervisor who oversees all of the phases of the project and directs advice in case that any mistakes might have occurred during the work. They must be familiar with all technical problems in the project. III. Laboratory worker who makes the electronics circuits boards and the worker who makes the robot bodies, et cetera. 2.2.2 Equipments resources: I. The robot components are the most important resources of the project, as it is the actual need of the project, where they also considered as the physical robot. II. The laboratory equipments are used to testing, power supplying, PCs, etc. II.1.1 Materials resources: I. The materials in my project consisted of programs, data sheets, books, lecture notes, hard copies from Internet sites, all of which are considered to be learning materials resources. II.1.2 Place and Time resources: I. The place is important when conducting the project as the project should be made at the laboratory because it is the most appropriate place to conduct this type of project as it needs all sorts of tools.

II. The project time is actually the project day, which is based on the student course time table. My project day was every Wednesday, though one day in a week was not enough to allow me to complete the project on time, so I went to the laboratory for extra days. II.1 Find the alternatives In the beginning of the project process, there were several options for several parts of the project. The first of these options was the programming language used to simulate the processor, where I had not decided what programming language to be used yet, because there are several programming languages that can support the field of robotics. When I referred to the lecture notes and experiments of the first and second years, it was clear to me that I studied the assembly language and I was very interested in it. As it supports the programming of the robots, I decided to use the assembly language to program the microcontroller. Other programming languages, such as C, C + +, et cetera, were also useful in programming the microcontroller. The other part was the stepper motor; there are many types of stepper motors for me to pick, but I decided to chose the right one after discussing it with the project supervisor, who advised me to use 5 volts stepper motors to be appropriate with the system power supplied, as the all robot components should be working with 4.7 to 5 volts. Then I had to order the parts from the Internet website after my supervisor agreed and signed the order form < http://uk.farnell.com/sanyo-denki/103h546-0440-1/stepper-motor-1-8deg-3-15v/dp/9948252 > . A similar problem was with the radio device, as I had to make the wireless device, so I needed the appropriate radio device; in fact I was going to make two of them, but when I discussed this matter with the supervisor he advised me to make just one, as one wireless device set as transceiver was enough to complete the project successfully.

<http://uk.farnell.com/easy-radio/er400trs/module-tx-433mhz/dp/5096558> 3 Drive by wire robotic vehicle project methodology. The methodology of the drive by wire robotic vehicle project consists of the sequence of certain stages which are effective on the success of arranging the project tasks. 3.1 What is the Project Methodology. I. The initial idea of the project that was very important was to decide what project methodology was to be used. The initial idea was provided by the University projects website, where the Coventry University offers many projects for the final year students and these projects are accompanied by an initial idea or explanation, which helps students to choose the appropriate project. The drive by wire robotic project was my choice after reading and after I had gotten sufficient concepts about the project, as it contains the control and radio wireless communication systems. Actually, it already supported my course, which is network and communication technology.

II. The implementation methodology is aimed to divide the whole practical parts of the project into a number of tasks, whereas each task contains several works. I began with revising the first year and second year laboratory experiments, then making small programs in assembly language to send and receive data by using serial communication interfaces preparing to make the robot control program. Then I had to do some control experiments on the stepper motor using the darlington driver to control the stepper motor into different directions, then order some components that were needed to make a wireless device, followed by making the PCB circuit board by using multisim and ultraboard programs to draw the schematic diagram. After this, I soldered the components on the circuit board and tested them, followed by using the MOSFTS to drive the stepper motor and then combined all of the components into the robot body. III. The project tasks and works should be done in time to void any lateness, whereas some tasks may be based on the other tasks to be completed before starting a new task. 3.2 Why chose this processing method? As the right methodology makes the project more easier and understandable, and once the tasks are divided into several works, the project will be clear to implement.

The division will specify who will do what and when, since the project is based on electronics components; by arranging the components into their right positions and connecting them in the right way and so on, this could help to avoid any technician problems, such as short circuit, interference, et cetera, and by testing each device or component, we will be help to maintain its performance to do as it needs to. 3.3 Is this the right method? The project implementation methodology is typical, because the project becomes clear by specifying what the tasks are. In other words, what I have to do to achieve the project. The tasks are clear and are based on several works, so when the tests results of each work is satisfactory, this mean that the current task has been done. It should also be made sure the task was done successfully, which is vital to moving on safely to the next task. 4 Building Robots : What is needed? As mentioned in the abstract, all robotics contains three main parts, which are the robot body, processors, and the programs, and these parts should be combined together by the appropriate method to create a good quality robot.

With the evolution of the work of these robots, it has become very important to add extra parts in order to carry out the additional works for the users. 4.1 Robot processors The processors (CPUs) are important to us, not just for building the robots, but because the robots are becoming common in our daily usage. They work to receive data from many different sources, which could be external devices, such as sensors, wireless devices, Bluetooth, switches, et cetera, and those that are considered as inputs, and process these inputs to give the required outputs specified programs or data. This data will be placed under the (ALU) arithmetic logic, registers unit, and the control unit carried by the data buses. 4.1.1 Microcontroller 68HC12 These became possible by using the high-tech producing small units of integrated circuits called (Microcontroller Chip), which are considered to be mini-computers designed to perform specific functions.

These MCU can perform programmed arithmetic operations and implement a number of commands that control the performance of many tasks for devices that we use, whether they are electrical, electronic or mechanical devices. Multiple tasks and functions of these units are according to the programs that you write and store them specifically for these posts. The microcontroller 68HC12 was upgraded from the previous model 68HC11 in the mid-nineties in order to perform developed instructions. Both of them supported the same programs, but 68HC12 Microcontroller has 16 bit and it is considered from the Freescale family as the maximum speed of bus is 8MHz and the size of the flash memory up to 128KB.

The 68HC12 has 16 bit divided into two accumulators, which are A & B 8-bit for each accumulator, the accumulator D is combination between A and B, which is due to it allowing for 16-bit operation, the other 16-bit for index register X and 16-bit for index register Y. The stack pointer has 16-bit, as well as the program counter, and the condition code register has 8-bit. 4.1.2 Microcontroller development board The Motorola company has introduced the T- Board HCS12 16 bit after having conducted several evaluations and the training board, development platform can be contributed to reducing the cost and time of the development, it is used achieve multiple targets, some of this targets is for the educational experiments, T-Board has made technically to serve MC9S12DP512 microcontroller, as it is providing some useful peripherals parts, some of these parts is voltage regulator, optical indicator ,acoustical indicator and CAN transceivers, RS232, DIP switch input device and potentiometer input device, many tools are helps the process of development can be used by the T-Board such as the (Monitors, C-Compilers, BDM-Debuggers), the technical data of the microcontroller are “ MCU MC9S12DP512 with LQFP112 package (SMD), HCS12 16-bit CPU, uses same programming model and command set as the HC12, 16 MHz crystal clock, up to 25 MHz bus clock using PLL Memory: 512KB Flash, 4KB EEPROM, 14KB RAM, 2x SCI - asynch. serial interface (e.g. RS232, LIN) 3x SPI - synch. serial interface, 1x IIC - Inter-IC-Bus, 5x msCAN-Module (CAN 2.0A/B-compatible), one channel equipped with on-board high-speed physical interface driver, 8x 16-Bit Timer (Input Capture/Output Compare), 8x PWM (Pulse Width Modulator), 16-channel 10-bit A/D-Converter, BDM - Background Debug Mode Interface, std 6-pin connector, Special LVI-circuit (reset controller), Serial interface with RS232 transceiver (for PC connection), Second serial port for IF-Modules (RS232, RS485, LIN...), 8x Indicator-LED, one Bi-color LED (adjustable via PWM), Sound transducer (buzzer), Reset Button, 8x DIP switch, two push button switches, analog input potentiometer, up to 85 free general-purpose I/Os, all MCU signals brought out on four header connectors around the MCU, arrangement compatible with Motorola EVB, Connector for wall plug power supply (not included), On-board voltage regulator generates 5V operating voltage, current consumption 50 mA typ. (plus LEDs etc.), Mech.

Dimensions: 80mm x 95mm” where the technical data is fixed so this has been quoted directly from the user manual referenced by. 4.2 Robot program. One of the hardest parts in robotics is the robot software program, or how to write robot program. The hardware part is easier because it consists of concrete components with a large amount of helpful information available almost in all research sources, such as data sheets, websites, articles, magazines, books, et cetera. The robot software programs need to make it specifically as the user needs it. This could be made through knowing the needed robot software program structure. To make the software programs, the user first needs to write the Pseudo Code, because the Pseudo code is written to clear the program requirements, as it is helpful to the programmer to be ready and clears ideas to write the program. In addition, it is useful for saving programmer time in case of program code writing, and it is considered as the module language similar to the English language, which describes the steps to make the program code. It is also similar to the algorithms to a large extent, where it describes the steps in a logical solution without paying attention to the rules of the programming language that will be used to make the program code.

As the Pseudo Code can be in any language, the programmer needs to specify which programming language they want to use to write the program code. Most programming languages support robotics and there are some factors that are helpful in deciding on the right language. The first of these factors is the programmer background; if the programme has knowledge about the specific language, this will be helpful to write the appropriate code in a shorter period. The second factor is the time and effort spent writing the complete program code. Some of the languages are complex and need a long time to do little work, and yet some of them are easy to make smaller codes in shorter time. The third factor is the programmer’s goals; the programmer should choose the useful language to write the code by comparing between which is more useful to make the robot’s specific job and to achieve the goals. The fourth factor is the availability, as some of microcontrollers do not support all of the programming languages, so the programmer should make sure to choose an appropriate language that is familiar with the microcontrollers.

Once the programmer has chosen the appropriate language, then it is time to start writing the Pseudo Code for the required program and draw the flowchart or UML diagram. 4.2.1 Assembly language The assembly language is considered a low level language of the earliest programming languages, including machine language. It has been named low -level because the programmers wrote the program’s commands in the similar CPU level, where the translated assembly language statements has been done in one machine language using (0, 1) in translation operations. My decision to use the assembly language in the project is based on my studying of this language in the first year in Coventry University, which has helped me to be familiar with it. In the third year it is a different matter, as I have to know more about the programming and study in depth this programming language. Program code structure: To write the assembly program code, we should know what the program structure is, as it consists of Labels, Mnemonic, Operand, and Comments. Labels : is an optional choice for the programmers to put in symbols, which are used to identify the memory location and the assembly modules positions. Mnemonic : Machines instructions and the directives assembler used mnemonic names to identify the operation. Operand: Is the assembler directives arguments field, it follows the operation field. Comments : This field is used to document the program code or to give an explanation at the end of each line code, * and ; used to write comments, the assembler ignores any comments (Huang 2002).

Drive By Wire Robotic Vehicle program code: The robot program code is very important to keep control over the robot’s movements. While there are several programs used to control the robots, in this project I focused on controlling the robot to move in different directions, which are FORWARD, BACKWARD, RIGHT, LEFT and STOP. This program has been done in assembly language. I have divided the program into sections to make it easier to understand. The first part of the program is the description about what the program used for, the author’s name, supervisor’s name, module code/title, project title and date as shown below: xx The second part of the program is about the initialization and definition of the variables, as shown below with comments: xx The third part is about the start with setting the memory location $3000 as the program counter, then setting PORTA as output by loading it in #$FF and storing the PORTA to the PORTA data direction register, as shown in the code below: xx The fourth part is describing the protocol used to the serial communication system by using MOVB instruction, which allows moving the values from another location memory or registers, such as giving the control register 1 :no parity, 8 data bit value and giving this line label NITSCI, the baud rate register low : baud rate 9600, enable to receive: control register 2, load accumulator A by control register 1 to clear the transmit data register, the STD used to put address flag to the data register high. xx

The fifth part of the program the line was given label READY followed by load the accumulator A into the control register 1 this is to reading the register status then masking the received data register full by using ANDA instruction and compare with zero the READY, if the READY equal to zero go to READY to read again if not contentious or execute the next line. xx The sixth part is considered as the actual robot control or the main body of the program, where the starting with loading the accumulator B data register low to read the characters then compare the accumulator B with the each specified characters such as ‘E’ character by using CMPB instruction, if the comparison process is satisfactory then move to execute operation by using BEQ which is used for branch to the specified mark such as “FORWARD”, where if the comparing process has un satisfactory, the processor will move to following comparison to compare with the next character and so on until reached the BRA instruction, the branch followed by label READY, which is go back to READY and read from the accumulator B or the data register low or COM port. xx The seventh part of the program is related to the stepper motor movements, where the stepper motor is moving by full steps, each direction contains four steps ‘see stepper motor section 4.3.2’, the code for moving the motor is starting with load accumulator

A with the specified byte and called the subroutine, at the end of these subroutines the compiler will go back again to read data from COM port. xx The eighth part is about the output and subroutine, where in previous part the OUTSTUP is used to executing one step and stored in the PORTA, followed by loading register X with delay value, next line given label BACK is to decrement register X ,BNE used if the X not equal to delay value the compiler will go back to decrement X until X register equal to the delay value then RTS used to return from subroutine followed in next lines by double ENDs used for end the program assembly xx 4.3 Robot components The robot project contains several components. I have mentioned the basic components, which are important to construct the robot. There are some of them that I am not going to mention in this report, such as wires, connecters, and wheels. 4.3.1 Body of the Robot The robot body is very important when combining all of the robot components together to be as one whole part. In this project I have chosen two layers built with one layer above the other. The reason of making it in this way is because the robot components need more space, as there are many circuit boards being used. One layer is not big enough to put all of them in one layer.

4.3.2 Stepper motors The stepper motors are devices that follow the controller instructions. They are driven by processed digital information expected to do the specific movements. Electrical stepper motors are applied digital pulses instead of contentiously supplied voltages. The main concept on these stepper motors is to drive the motor in steps; each pulse will equal one step. To drive the stepper motor to do specific work or to make it move in any direction, it needs a counted number of pulses; as to move the stepper motor 270 degrees, or in one complete cycle based on the number of pulses flows. It can control the stepper motor in more precision by specifying the steps revolution, where if the number of steps are increased, then the stepper motor is controlled in more precision. To get more precision on the stepper motor, it can use the driver. The stepper motor driver performs by dividing one step into a number of steps, or half steps and micro steps. Figure 7 below shows how the stepper motor is driven by pulses in one step and counted steps, and Figure 8 shows that one full step equals two half steps. The stepper motors use rotators to implement the step movements, where it is considered as an electromagnetic device, which is uses input pulses to move that rotator by converting it through the mechanical shaft rotation operation. The stepper motor has the ability to get a specific position with loading. However, it does not need to stop to get them where it can be done between the steps, so it can be controlled on the rotator by rotating through mechanical movement by counted number of steps. It can specify the required distance, and the advantage of this is the ability to let the stepper motor run this operation as much as the specified number of times. Also, the stepper motor can be moved in two directions, which enables it to turn into a specific direction when using two of them. As its using the synchronization property, it can also be controlled on the speed of rotator motion or stop motion in specified time, as its useful to many uses in mechanisms; in addition, it doesn't drift during low rotor, which means there is no error possibility while this operation is active.

The stepper motors’ pricing is based on the motor performance, as the performance of the stepper motors is measured in percentage. How much is the error positioning? How much is the positioning accuracy? Where the DC servo is likely to be the best and most expensive, it is because of its low error positioning and high positioning accuracy. In my project, I am using the Sanyo Denki Model 103H546-0440 Stepper Motor (Anaheim Automation 2010a). 4.3.3 MOSFETS The transistors are the devices that allow small changes in voltage to switch things on and off; the kind similar to the valuing plumbing system, though instead of controlling the flow of water, it can control electric current, which makes things as simple as possible. I am only going to explain the easiest type of transistor to work with, which is the Bipolar transistor N- channel MOSFETS. As there are many types of MOSFETS, I am going to give an introduction of the type which I have used in my project. The word MOSFET is the short name for Metal Oxide Semiconductor Field Effect Transistor. The one I used in this project is the silicon N-channel SP8K3, whose features of the MOSFET are low on-resistance, built-in G-S Protection Diode, and small surface mount package (SOP8); actually, the MOSFETS used, as power switching, the DC / DC converter. In this project, I have used this MOSFET to drive the stepper motor and to keep control of the motor direction, shafting the motor position, and to control speed.

To drive one stepper motor, we needed two MOSFETS in one circuit board, known as MOSFETS DRV, as shown in Figure 11 below. 4V Drive Nch+Nch SP8K3 MOSFET contains 8 pins; pin 1 and 3 are source pins, which are connected with the circuit ground; pin 2 and 4 are gate pins, which control the transistor on and off; pins 5, 6, 7, 8 are called drain pins, which is the pin that the current is draining as shown in Figure 10 above. 4.3.4 Radio Device In this project, the control method used was wireless controlling, where there are two wireless devices being used, one of which was provided from the supervisor and the other one I made by myself. The concept here was to connect the wireless device with the PC and the other one should be connected to the robot itself. The wireless device was based on the radio device, which has the ability to transmit and receive data. In the project, there was no need to transmit data; it just needed to receive data from other sender device.

Here is an explanation for the radio device that was used in this project. The radio device is from the ER (EASY RADIO) family, ER400 TRS is its transceiver, which can be considered a sub-system because it can combine a “high performance very low power RF transceiver, a microcontroller and a voltage regulator, the radio device used serial input output data using 19,200 baud rate as standard, the host using handshake protocol to follow control, 180 bytes can be used to send and receive”. More technical details are provided in the device data sheet. 4.3.5 Power The power source is very important in the project, as without power the system will never work. The power is used to supply different components in the robot. I have used the 5V DC supplier to operate the system, where the microcontroller needs 5v supplied directly from a 5 volt power supply, as well as the parallel board, but the stepper motor needs 3.7V to 5V, which can be gotten from the DC power supply. 12V needs to supply the wireless device, which can be used on a DC power supplier. The DC power supply needs extra care while using it, as sometimes a short circuit would occur, which can be detected by the DC power supply LED, meaning that the current is limited and its need to increase the current by adjusting the current to avoid the limitation. Other power problems have occurred during the implementation, which will be explained in section 8.2 Wireless Control Test. Figure 13 below shows the stepper motor supplied with 3.7V by the DC power supply. 5 Robot relationship diagram The robot consists of eight elements that are set together to perform as a robot vehicle:

1- The robot body (consists of two layers and two motor hangers). 2- Robot wheels (three wheels are used, one is in front and two are in the back, connected with two stepper motors). 3- Two stepper motors each have six wires, four of them are connected with the MOSFET and the two remaining are connected with the power. 4- Two N-channel MOSFETS drivers, four inputs and four outputs, the table below indicates the actual connection between the MOSFETS and the stepper motors: xxx 5- Microcontroller 68HC12 (the flexible cable has connected between SCI1 and RS232, power connected to the external battery, PORTA from B0 to B7 are connected with two MOSFETS. 6- Power supply: the Microcontroller, stepper motors, and the wireless device. 7- RS-232 has two connectors, one is DB9 that is connected with the wireless device and the other one is a flexible cable that is connected to the SCI1 terminal in the microcontroller. 8- Wireless device that has DB9 female pins connected with RS-232 to be able to control data communications by transceiver device. ...Download file to see next pages Read More