Automatic Room Temperature Control System

Running head: CONTROL SYSTEM
CONTROL SYSTEM
Name of Student
Institution Affiliation

CONTROL SYSTEM 2
Table of contents
Contents
Table of contents.........................................................................................................................................2
Table of figures...........................................................................................................................................2
List of tables................................................................................................................................................3
Description of the Control Objectives.........................................................................................................3
Background information..............................................................................................................................4
Objective Selection......................................................................................................................................6
Identification of the Control Objective........................................................................................................7
Performance of Controller...........................................................................................................................8
System Implementation.............................................................................................................................11
Abstracting the Problem............................................................................................................................14
Problems Faced.........................................................................................................................................15
Software Configuration.............................................................................................................................15
Conclusion.................................................................................................................................................17
References.................................................................................................................................................18
Appendix...................................................................................................................................................20
Table of figures
Figure 1: Showing the block diagram with the major parts of the system......................................6
Figure 2: Showing System flow chart.............................................................................................7
Figure 3: Showing Circuit diagram of the Automatic Room temperature Control system showing
all components of the system.........................................................................................................10
Figure 4: Showing the settling time and stability of the system with PID controller....................12
Figure 5: Showing the settling time and stability of the system without PID controller...............13

CONTROL SYSTEM 3
Figure 1: Showing the block diagram with the major parts of the system....................................16
Figure 2: Showing System flow chart...........................................................................................17
Figure 3: Showing Circuit diagram of the Automatic Room temperature Control system showing
all components of the system.........................................................................................................18
Figure 4: Showing the settling time and stability of the system with PID controller....................19
Figure 5: Showing the settling time and stability of the system without PID controller...............20
List of tables
Table 1: showing List of materials required during implementation..............................................8

CONTROL SYSTEM 4
Description of the Control Objectives
This project will address the control system of a room temperature which is
automatically controlled. This hence means that there will be a set temperature known as the
desired temperature. This control system of the room will be realized by some actuators like a
motor which will switch on the fan if the room temperature is below the reference (set)
temperature. It will also employ the use of a magnetic relay (contactor) which will turn on the
electrical heater when the temperature of the room is below the desired temperature (Kurniawan,
2016).
The whole process is done automatically hence there should be individual physically
turning on the fan when the temperature is very hot or switching on the electrical heater when the
temperature is very cold. Therefore this will require the use of a microcontroller which will be
programmed to help realize all these required parameters (Jusoh, 2010).The actuator will be
communicated by the sensor which will detect the temperature of the room and transmit the
value to the microcontroller to do the comparison between the actual readings and the desired
value before any action is carried by the microcontroller.
Background information
With the new advancement we have nowadays, the machine, computing and automation
have become our part of living. A house is actually the most inhabited in any culture in the world
and humans have tried their best to make the rooms in the houses to be even more comfortable
by providing any environmental condition they would like (Lipovski, 2014).In our houses, the
living room and the bedroom requires to be kept within inhabitable temperature ranges. This
issue is becoming more important for homes /houses with very young children (infant). It is
normal for a grown up (adult) to find his /her way out of the discomfort zones but it won’t be

CONTROL SYSTEM 5
possible for the infant or sometimes it won ́t be possible during some times like night
(Bhattacharya, 2011).
Again we may need some particular temperature in some places in our houses for
example where perishable goods are kept a very cold temperature is required. This will hence
require the use of the control system in room temperature (Arora, 2010). The idea of the
programmed room temperature control system started back during 18th C and the first person
people believed had this idea was from Norman School in Oklahoma and his name was Warren
Jonson. Before this time Janitors could be sent to go out and find the temperature in every
classroom thereafter Janitors will control the dampers in S basement.
Johnson watched this and then he thought of a good approach to stop all these suffering
Janitors were going through or even limit the problem. Johnson then thought of the automatic
room temperature control system (Leigh, 2012).During the mid-21st C, this control system
resulted in noticeably famous in many homes. Currently, a good measure of work is done and
completed by societies in this sector. A good deal of automatic room temperature control system
products is promptly attainable in the market for example AIRCONS. Weather is something
which keeps o fluctuating and their fluctuations can occur in a very short span of time and this
can lead to external conditions which influence indoor weather condition like temperature.
This paper hence addresses the room temperature control system. Basically, this is like an
air conditioning system that observes the temperature of the room and manages the fresh air
movements in the room without having any person ́s involvement. The system will make good
use of the temperature sensors, microcontroller and actuators (fan and heater). The temperature
sensor will take the temperature readings and communicate it with the microcontroller
(UnbehauenHeinz, 2011).

CONTROL SYSTEM 6
Objective Selection
An automatic room temperature control system basically is a self-controlling
temperature where the utilization of the set point is key and it helps in maintaining the room
temperature whether it is hot or cold outside (Passino, 2014).This system will enable the operator
to put the desired temperature, the desired set temperature will be compared against the actual
temperature of the room with the help of sensors for taking the measurement and microcontroller
for comparing the two temperatures. The system will respond by turning ON either the cooler or
the heater depending on the difference after the comparison. This difference done by the
microcontroller is illustrated by the equation below;
Temp diff = Set temp – Actual temp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
When the temperature difference is positive it implies that the set temperature is higher
than the actual temperature hence it is colder outside and for this situation, the microcontroller
will turn on the heater to heat up the room. But in cases where the temperature difference is
negative, it means that the actual temperature is higher hence the environmental temperature is
higher, therefore, the microcontroller will turn on the cooler (fan) to help bring back the
temperature to the desired set value (Bequette, 2012).This will make the system to automatically
control the temperature of the room and tries to make it constant at the required value but it will
be very difficult for this to happen.
This is difficult because of the heating will go higher when the heater tries to reset the
temperature to the desired value. When the sensor detects the same temperature between the
desired temperature and room temperature, it will communicate this to the microcontroller which
will stop the heater (Berenguel, 2014).The heater will be switched off yes but it will still be
giving some higher temperature before it cools and during that time the heater releases some