1. Microcontroller Based Real Time Sequential
Starting System
Isheanesu Chitsvare, B.Tech (Hons) Electronic Engineering
Harare Institute of Technology
May 2014
ichitsvare@gmail.com
Abstract - The microcontroller based sequential
starter was developed in this project. It is a project
that controls the start and stop times of AC motors
using real time clock. The project consist of DS1307
real time clock, a computer and LCD all interfaced to
PIC18F452 microcontroller. The project also uses a
USB to RS232 convertor to cater laptops that do not
have RS232 ports. A windows user application was
developed on Microsoft Visual Studio software using
C# programming language. This application enabled
the user to enter different start and stop times of the
AC loads. The windows application communicates
with the microcontroller through standard PC serial
port. The microcontroller receives input t from the
computer and executes the sequence of start-up and
shutdown time. During execution the microcontroller
compares the entered time from the computer with
that of the DS1307 running real time clock. If the any
of the entered times matches the time on the real time
clock the microcontroller executes as per set
instruction. The DS1307 was interfaced to the
microcontroller using the I2C communication
protocol. The microcontroller program was developed
using MikroC for PIC IDE. This project was designed
to control the start and stop time of three AC motors.
Single phase AC motors were used for demonstrations
and were interfaced to the microcontroller using solid
state relays. The results of this project came out as per
expectations implying that the motors were turned on
and off using the entered time from the computer.
Index terms: C#, microcontroller, real time clock
I. INTRODUCTION
Due to great reliance on technology, automation
has become of greater need in manufacturing industries.
Automation has taken the lead in production industries. In
today’s competitive industry marketplace, the companies
face growing demands to improve production time,
process efficiencies and meet corporate financial
objectives. Given the increasing age of many industrial
systems and the dynamic industrial manufacturing
market, intelligent and low-cost industrial automation
systems are required to improve the productivity and
efficiency of such systems (Gungor and Hancke, 2009).
Manufacturing has been evolving over the years as
different needs and technologies arise. The customer of
the twenty-first century, demands products and services
that are fast, right, cheap and easy (Dangayach and
Deshmukh, 2001). The changes in manufacturing systems
and industrial structure brought about by the development
of new, computer-based flexible technologies (Taymaz,
1990).
Automation plays an increasingly important
role in the global economy and in daily experience.
Engineers strive to combine automated devices with
mathematical and organizational tools to create complex
systems for a rapidly expanding range of applications and
human activities. Some advantages are repeatability,
tighter quality control, and waste reduction, integration
with business systems, increased productivity and
reduction of labour. Some disadvantages are high initial
costs and increased dependence on maintenance.
A major benefit of industrial automation
technology is the latest fieldbus developments. The most
popular protocols are Device Net, Provirus and Asia and
the emerging Industrial Ethernet. Implementation of
industrial automation provides capital expenditure
savings associated with cable elimination (multiple
devices share wire-pairs and communicate over the bus
network) and other savings are also available through
speedier commissioning. A major advantage of industrial
automation and process control is the increased emphasis
on flexibility and convertibility in the manufacturing
process. Manufacturers are increasingly demanding the
ability to easily switch from manufacturing a wide range
of products without having to completely rebuild the
production lines.
In Zimbabwe, automation is now expanding
into small and medium enterprises. Mostly in industries
automation is appreciated through PLCs, but the
production processes in these small/light industries do not
require huge expensive control units. But require simple,
cheap automation through use of microcontrollers and
computers. Most devices are now computer operated and
the user can input commands to control other devices.

2. Due to this lack of automation much human error is seen.
This project incorporates real time operation and serial
interface were the operator inputs start time and stop time
of the electrical machines via the computer.
II. SYSTEM DESCRIPTION
This project was aimed at designing and building a
Microcontroller based real time sequential starting system
to control AC loads. An operator will be able to input turn
on and turn off times of Ac motors using a computer. The
AC motors were connected to the microcontroller via
solid state relays. This system therefore gives the operator
the flexibility of controlling the sequence of turn on and
turn off times using a computer without physically
switching machines one by one which can be a tedious
task for a big plant. A windows interface application was
written in C# and can be installed on any computer which
can run visual studio programs. This interface
communicates with the serial ports of the computer. This
will then involve serial communication of the computer
and the microcontroller unit. The system also uses a USB
to RS232 converter. This converter uses the USB port to
communicate with a virtual serial communication port
created by the software which runs the converter.
Through this converter, data will be sent serially to the
microcontroller, which then configures the motors
according to the sequence set. The program loaded on the
microcontroller will determine which pin to send a high
or low signal to and thus turn on or off the desired motor.
The system is also able to correct the real time to match
the time on the computer. After configuring the sequence,
the microcontroller will perform the sequences and wait
for the user to set another sequence. Also during the
execution the sequence can altered. The prototype was
designed to control the sequence of three AC motors.
III. SYSTEM IMPLEMENTATION
i. The Windows Application.
The windows application was designed to run on any
windows operated computer. The application operates in
different modes: the normal mode and the time
modification mode. The application uses commands to
enter into different modes: s to set the sequence and q to
modify the time. The application was designed to operate
on a specific COM port with set parameters such as baud
rate, stop bits etc...
Hardware and software implementation.
Both the microcontroller and the windows application
were set to use the same communication parameters. The
microcontroller receives and interprets the serial data
from the windows application. The microcontroller is
interfaced with a real time clock which provides the
running time used for comparison with the entered
start/stop time. The system used MAX232 to translate the
voltage levels of the serial communication protocol. The
AC motors were interfaced to the microcontroller through
zero crossing solid state relays
IV. SYSTEM OPERATION
The user uses the windows application to configure the
starting and stopping sequences of three motors.
Figure 1: Windows application interface
To start the operation the user must first of all connect to
the serial port using the connect/disconnect button shon in
Figure 1. The same button is used to disconnect. On
connection the application prints connected in the
message box also for disconnection prints otherwise. The
windows application sends data to the microcontroller
circuit using USB/RS232 adapter to cater for computers
that do not have RS232 serial ports. The microcontroller
receives the serial data and performs the executions.
During execution the microcntroller monitors and
compares the time from the real time clock with the
entered start/stop time for each motor. For sequence
setting, the system prompts the user to enter start and stop
times for motor 1 to motor 3. The entered time is then
converted to binary coded decimal so that the time can be
compared with that of the DS1307. An additional feature
added to the operation of the system is the ability to
modify time so that it can sync with the computers time.

3. V. CONCLUSION
The aim and objectives of this project was met. The
windows application and the microcontroller circuit
functioned as to expectations. For future use the system
need to be upgraded so that it can operate on a wide
variety of COM ports. There will also be need to monitor
and control voltage and current levels of the motors and
also to alarm start and stop failure of the motors.
REFERENCES
BOOKS
Mazidi, M., Mazidi, J., and McKinlay R (2006), The 8051
Microcontroller and Embedded Systems Using Assembly
and C. 2nd
edition. London: Prentice Hall.
Ibrahim, D (2008), Advanced PIC Microcontroller
Projects in C from USB to RTOS Elsevier Ltd
JOURNALS
Gungor and Hancke, 2009. Industrial Wireless Sensor
Networks: Challenges, Design Principles, and Technical
Approaches
Aakvaag, N. Mathiesen, M. Thonet, G ‘Timing and power
issues in wireless sensor networks—An industrial test
case,’ pp. 419–426.
Dangayach and Deshmukh, 2001 ‘Advanced
manufacturing technology implementation Evidence from
small and medium enterprises (SMEs)'.
Meha, S. haziri, B. Gashi, L. Fejzullan ‘Controlling DC
Motor Speed Using PWM from C# WINDOWS
APPLICATION’.
Tiponut, V et al (2007) C# and .NET Framework for uC
Communication Protocol Implementation
Adewale, A. Isaac, S. Awelewa, A. Ike, D (2013). Design
and Development of a Microcontroller Based Automatic
Switch for Home Appliances
THESES
Jarwal, N. RTC Based automated farm, Submitted for the
Degree of Bachelor of Technology in the division of
Electronic Engineering and Telecommunication, MIT
College of Engineering Pune.
Amala, A and Raghunath ‘Real Time Clock’. Submitted
for the award of Degree of Bachelor of Technology in
Electrical and Electronic Engineering, Jawaharlal Nehru
Technological University.
Noor, A. ‘Real Time Clock Display using Programmaing
Language Approach’. Submitted in partial fulfilment of
requirements for the Bachelor Degree in Electronic
Engineering, Kolej Universiti Teknikal Kebangsaan,
Malaysia