Control of the locomotion of temperature sensor

Abstract

Embedded system devices are used to detect changes in the environment through sensors and other hardware and respond to human commands. The sensors used to detect changes in the environment, in the already existing systems are fixed in a certain place and cannot be moved easily. A small device is built which can be used for movement of the sensors to different locations effortlessly. It can be used in industries to mount the temperature sensors and move them to remote locations to detect changes in the environment. The data collected by the sensors can further be used for analysis. This is achieved using the microcontroller (ATmega8) which uses the embedded C program for control of the device and the interface. LM35 is the temperature sensor used to detect the temperature. L293D is the IC used for the stepper motor and microcontroller interface. The device controlled by the user moves to different locations senses temperature. If the temperature is above a given threshold, the output is given as buzzer. An algorithm is written to combine the movement, temperature measurement and the buzzer.

Full text

International Journal of Applied Engineering Research
ISSN 0973-4562 Volume 10, Number 6 (2015) pp. 14405-14419
© Research India Publications
http://www.ripublication.com
Control of the Locomotion of Temperature Sensor
Malvika Devaiah M1, Sandhya K.S2 , Akshay S3
Department of Computer Science, Amrita Vishwa Vidyapeetham,Mysore,India.
mooderamalvi@gmail.com1,sandhyakedambadi@gmail.com2
akshay_rao26@yahoo.com3
Abstract
Embedded system devices are used to detect changes in the environment
through sensors and other hardware and respond to human commands. The
sensors used to detect changes in the environment, in the already existing
systems are fixed in a certain place and cannot be moved easily. A small
device is built which can be used for movement of the sensors to different
locations effortlessly. It can be used in industries to mount the temperature
sensors and move them to remote locations to detect changes in the
environment. The data collected by the sensors can further be used for
analysis. This is achieved using the microcontroller (ATmega8) which uses
the embedded C program for control of the device and the interface. LM35 is
the temperature sensor used to detect the temperature. L293D is the IC used
for the stepper motor and microcontroller interface. The device controlled by
the user moves to different locations senses temperature. If the temperature is
above a given threshold, the output is given as buzzer. An algorithm is written
to combine the movement, temperature measurement and the buzzer.
Keywords: Mobile temperature sensor, Obstacle detection, Atmega8.
Introduction
Embedded system is emerging rapidly in the field of computer science. There is an
acute need for sensors and robots in almost all industries and work areas. The robots
can go to places where humans cannot go, the devices can sense just like humans.
This makes a human’s work easier and efficient. They reduce man power and are
more accurate than humans. These machines can be built by using microcontrollers
and some sensors. Microcontroller has inbuilt peripherals that reduce the number of
external components to design a circuit. The features it has are general purpose
input/output, flash memory, serial IO, and communication protocols like bus and
timers. These microcontrollers coordinate with the sensors to collect the data. The
data which is collected by the sensors can be sent through wireless antennas or wired

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cables to the receivers of the main system. The movement of the device can be
controlled using the motor drivers like L293d. There are large sensor systems like the
robots (asimo, kismet etc) which are complex to build and are used in complex areas.
They can be used as multipurpose systems. Other smaller and simpler sensors are
used for specific purpose. Some systems may use many sensors whereas others use
only one sensor. Then a network of sensor system can be formed.
The sensors used to detect changes in the environment, in the already existing
systems are fixed in a certain place and cannot be moved easily. They cannot be
moved from one place to another place easily. They have to be manually removed
from the current place and then be placed in the new area of work. This poses a
problem when we have to sense data from different places (nearby places). One
solution will be placing many sensor nodes nearby i.e. a wireless sensor network, but
this will increase the cost of the system. Hence a small device is built which can be
used for movement of the sensors to different locations effortlessly. The device may
use the geared motor and motor drivers for the movement. The interface of the device
and the user can be achieved by programming a microcontroller. It can be used in
industries to mount the temperature sensors, smoke/gas sensors (methane, butane,
LPG etc) and many other sensors and move them to remote locations to detect
changes in the environment. The present work focuses on the temperature sensing
area. The data is used to check for the threshold value. If the temperature crosses the
threshold value, a buzzer is activated as the output for the users.
This work is achieved using the microcontroller (ATmega8) which uses the
embedded C program for control of the device and the interface. The microcontroller
is programmed to work according to the user’s needs. LM35 is the temperature sensor
used to detect the temperature. The LM35 gives output in analog form. L293D is the
IC used for the geared motor and microcontroller interface. The software for the
microcontroller is programmed using the embedded C program. This program is used
to interface between the components and the working of the system.
Literature Survey
When comparing the devices built previously there are different approaches adopted
by different people to build the sensing systems. Their purpose also differs but the
main concept remains the same. Consider, the mobile temperature sensing application
which uses bluetooth [6]. The device uses the PIC microcontroller and buletooth for
communication. It is used to check the temperature of the human body. In a similar
way, a wireless system for smoke and fire detection [16] checks the temperature and
gas in the environment and then senses the fire in the surrounding environment. It also
has the ability to extinguish the fire. The two devices though senses temperature, the
uses are different. Another application is developed for environment monitoring [5]
i.e. the environment temperature and the humidity is monitored via a android
application and the output values are displayed in the phone screen. For medical
reasons, a wireless temperature sensing and heart beat sensing microcontroller based
device [8] is built. This is a small device with more accuracy. It senses the
temperature and heart beat of the patient. At the time of emergency (acute changes in

Control of The Locomotion of Temperature Sensor 14407
the measured values) a sms is sent to the doctor or the next kin of the patient. These
systems which we have seen till now are single node i.e single devices. Further
studies found that devices are built such that a network is formed for coverage of
large areas. A prototype node [2] is built, to sense the temperature, humidity and
occurrence of flammable gases such as methane, butane etc. These values can predict
that there are any chances of forest fire. This helps in predicting the forest fire before
it occurs. Similarly, an automatic fire sensing robot with fire extinguishing feature
uses the GSM [17]. It has four nodes for sensing the fire by temperature changes.
This, when fire is detected sends the location to the extinguisher. The extinguisher
moves to the given location and the fire is extinguishes. These devices sense the fire
after the fire has started. Hence, another sensing sub system [15] was developed that
senses the temperature changes and the gas in the environment to predict the fire
before it occurs. The sub system sends a sms or alarm is sounded so that the family
(people in the house) can move to a secure area.
When it comes to industries which use harmful and flammable gases, gas sensors
are used to protect the workers in the industries. A node [14] is built to monitor the
harmful gases like methane, butane etc. The node sends an alarm through Xbee
module if it detects any harmful gas leakage. In mines also there will be gases which
are harmful. Here the node detects these harmful gases and sends information to the
workers for their safety.
When movement of devices is considered, many locomotive robots are built using
different methodologies. The most common mini locomotive robot is the line follower
robot [13]. This robot uses the pre-defined line for its movements. It has the capability
to follow white line or black line. The white line follower, on a black background uses
the light sensing method to follow the line whereas the black line follower on a white
background uses magnetic fields to follow the black line. Here the user does not have
the freedom for movement of the robot. It always follows the pre-defined line. A
better robot which has two legs is developed [3]. This robot has walking capability as
it uses four servo motors. It needs two power sources for the maintenance of the
robot. Then there is movement, obstacles pose a major problem. Therefore, to solve
this problem, an obstacle avoiding robot is built. It uses the IR sensors to measure the
distance from it to the obstacle. An obstacle avoiding robot is built [11] which moves
towards the destination by avoiding the obstacles. For better performance, a device
which combines many fertures can be built like the 4 in 1 robot [1]. This device has
four features. They are 1. Line follower 2. Edge detector 3. Obstacle Detector and
4.Path Finder it can be considered as the modified and complex version of pervious
devices.
Comparing all these systems we can conclude that each device is a modification of
previous ones. They have different applications and use different components and
different methodologies for the working of the system. Some consider accuracy as a
key feature, some other devices consider better application, other devices a meant for
safety for the humans and many other applications.
There are many places where the temperature has to be checked, monitored for the
help and safety of the users. Some of the places where there is danger for the humans
due to temperature are: in the place of fire , where for the firefighters safety, the

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temperature of the area has to be measured to make sure whether the firefighter can
go the preferred area or not. In military applications, the solider need to go to areas
where there is fire due to blasts etc. Here also this system can be used. In industries
where metals are being melted, we can use this device to measure the temperature of
the furnaces and give output as buzzer when the preferred temperature is reached.
These systems are implemented by other people by using different microcontrollers
and communications. These devices on the whole are costly and use many hardware
devices. Hence, in the current work we are trying to reduce the price of the device and
make it user friendly and efficient. This will help the fire fighters, soldiers in military
and the people working in the industries.
Figure 1: Pictorial Representation
System Components
The hardware components used in this system are:
A. Microcontroller
Atmega8: This device is used for control and interface of the whole system. It is built
by Atmel Company. It is an 8 bit microcontroller with RISC architecture. It has single
clock cycle execution. The throughput is 1MIPS/MHz It has 32*8 general purpose
registers and 6 ADC channels. It comes in 28 pin DIP(dual in line package). This
component is used for the interface of the device between the user and the mobile
device. The programs are written to this component for the working of the whole
system. This is the heart and the brain of the entire device.

Control of The Locomotion of Temperature Sensor 14409
Figure 2: Microcontroller
B. Temperature sensor
This device senses the temperature from the environment and gives the output. It has
a Linear + 10 mV/°C Scale Factor and has a range of Full −55°C up to +150°C. This
temperature sensing module gives out put in the analog form i.e. for each rise in °C,
voltage increases by 10mV. This voltage value has to be converted to digital form and
then compared with the predefined threshold value. When the temperature crosses the
threshold, buzzer is given as output.
Figure 3: Temperature Sensor
C. Motors
Geared motors are used for the movement of the device. This reduces friction. The
interfacing of the motor with the microcontroller is done using the L293D IC. This IC
is the motor driver IC. It can be programmed to control the motors. The driver is
helpful for the reverse movement of the motor without changing the polarity of the
power supply. The movement of the device is controlled using to geared motors. One
power supply of 5V is sufficient for the motors.
Figure 4: Geared Motor

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D. DTMF module
The DTMF( dual tone multi frequency) module is used for the communication of the
device with the user. This uses the keyboard of the cell phone by treating it as the Hex
keypad. The cellular communication between the cell phones is used as the
communication medium. The user can control the devices from his/her phone. The
key press from the cell phone is converted onto a unique frequency value. This is sent
to the receiver which is mounted on the device. The receiver decodes the frequency
value to produce a binary equivalent value. Based on this binary value, conditions are
set and the working of the device is programmed.
Figure 5: DTMF Module
E. IR sensor
The current device uses the IR proximity sensor. This module is used to find the
distance between the obstacle and the device. Based on the result of this sensor, we
can build line followers, edge detectors etc. In the current device this sensor is used
for obstacle detection. The distance between the obstacle and the robot is measured by
the sensor. Depending on the closeness (less distance indicates that the object is
closer) of the obstacle the robot stops.
Figure 6: IR Proximity Sensor
The software components used in the system are :
A. Fritzing
For the hardware setup and simulation a software called the fritzing is used. This
software is used to build the hardware in the computer to check the connections and
working of the hardware. Fritzing is open source software. With Fritzing, you can
design and sketch electronic circuits. Because there are many representations of
electronic circuits, this tool provides semantic design, breadboard and a PCB design
tool. It has many inbuilt features and supports design of microcontroller based
products easily. The hardware of the current device is built by using this software.

Control of The Locomotion of Temperature Sensor 14411
The module- temperature sensing module, movement module, obstacle detection
module and the buzzer module is built and checked for correctness.
Figure 7: Fritzing Software
B. AvrStudio 4
This software is used to build the program code for the AVR (Advanced Virtual RISC
machines) microcontrollers. The codes are written in embedded C programming
language. It uses the GCC compiler (GNU common compiler) to convert the
embedded C program to Hex format. This Hex format is the assembly language code
for the microcontroller. This is one of the simulator for the embedded system.
Figure 8: AvrStudio4 Software
C. AVR-boot flasher
The boot flasher software is used to burn the hex code given by the GCC of the
simulator to the microcontroller’s memory. This software searches for the hardware
connected to the computer’s port. When the device is found, the hex code is
transferred to the memory of the microcontroller. The program written by the
AvrStudio4 software has to be converted to hexadecimal format while saving. This
hexadecimal file is loaded to the microcontroller’s memory by the bootflasher
software.

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Figure 9: Bootflasher Software
Fundamentals Concepts
The main concept used in embedded system is the simulation and emulation of the
system. The main system is divided into subsystems. These sub systems are modules.
The modules are built independently and then combined to form the entire system.
Hence a lot of synchronization is required. The current project in divided into 3
modules. They are communication, movement and temperature sensing. The hardware
is built and tested using the fritzing emulator software. The software is tested using
the AVRstudio4setup. In the same way the movement and the temperature sensing
modules are completed. After the emulation is completed the hardware is set up using
the hardware devices with the help of the circuit created by the fritzing software. The
communication module is integrated and the working is tested. The embedded C
program is converted to hexadecimal code by the bootloader software. This assembly
level code is burnt to the memory of the microcontroller. Therefore, the complete
system is setup.
Implementation
The overall implementation is done in two parts:
 Software implementation
 Hardware implementation
The software implementation is used to simulate the sytems ,write the program,
compile them and then convert the program into hexadecimal code. The
implementation of the hardware is also done using software. The software called
fritzing is used to emulate the hardware setup. This is tested and the correct hardware
dirgram i.e the circuit, PCB design and the breadboard design is given as output. This
is then taken up by the hardware implementaion part. By using the friting software
output, the hardware is setup. Then the bootflasher software is used to store the

Control of The Locomotion of Temperature Sensor 14413
hexadecimal code to the memory of the microcontroller. The device is given power
supply and the project is implemented. The hardware is purchased seperately and
combined according to the output of the fritzing software.
A. Software implementation
The software implementation is started by testing the code in the AVRStudio4Setup.
Here the program is written in embedded C programming language. Then the program
is built to test the working of the system. The errors are corrected and the final error
free program is converted into the hexadecimal code which is the assembly level
code. This is the output of the AVRStudio4Setup software. This output is the input to
the bootflasher software which loads the assembly code to the memory of the
microcontroller. The hardware testing is done by using the fritzing software. This
software has the features to implement and test the hardware so that it wil be easy to
setup the hardware without the risk of the hardware getting burnt due to wrong
connections. The code for the hardware can also be tested by using this software.
B. Hardware Implementation
The hardware can be implemented only after the testing of the hardware working is
done in the fritzing software. The working circuit is got from the fritzing software
output. This is then used to build the hardware. Each component is first made into a
module. This module is then integrated to form the final hardware of the system. The
modules can be built independently as program written for it is loosly coupled.
C. Methodology
Hardware setup: The hardware- microcontroller, motor driver, geared motors,
temperature sensor, buzzer, transmitter and receiver is connected to build the circuit.
Communication: The wireless DTMF (dual tone multi frequency) module is used
for the communication between the computer (transmitter) and the device (receiver).
Movement: The movement of the device is controlled by the user through the
DTMF module and the microcontroller coding.
Temperature sensing: The temperature sensor(LM35) is used to sense the
temperature from the environment and gives the output through buzzer if the
temperature crosses the specified limit.
Obstacle detection: the obstacle is the path of the device is sensed by the IR
sensors and if there is any obstacle, the movement stops.
D. Algorithms
1) Movement module
A Cell phone mountain on a device is kept in auto answering mode, once the setup
connection is done:
Case 1 :
If 2 is pressed :
Move forward

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Case 2 :
If 4 is pressed:
Move left
Case 3 :
If 6 is pressed :
Move right
Case 4 :
If 8 is pressed:
Move backward
Case 5 :
If 5 is pressed:
Stop
2) Obstacle detection module
Step 1 : receive the left and right sensor values.
Step 2 : if (right sensor= on & left sensor =on )
Stop
Step 3 : if (right sensor= off & left sensor =on )
Stop
Step 4 : if (right sensor= on & left sensor =off )
Stop
3) Temperature sensing module
Step 1 : initialize int temp= 0;
Step 2 : temp = analog read (value from pin)
Step 3 : convert analog value to digital value
tempC = (5.0 * temp * 100.0)/1024.0;
Step 4 : if ( tempC > 55 )
buzzer on
Step 5 : if ( tempC < 55 )
buzzer off
4) buzzer module
Step 1 : set 4th bit of port D as output port.
Step 2 : if (bit 4 is high)
Buzzer on
Step 3 : if (bit 4 is low)
Buzzer off

Control of The Locomotion of Temperature Sensor 14415
5) Algorithm for mobile temperature sensing device
Step 1 : initialize values :
Int button, left_sensor, right_sensor, temp=0
Step 2 : set PB1,PB2, PB3, PB4 as output bits. (for motors)
Step 3 : set PD7, PD6, PD5, PB0 as inputs for the DTMF input.
Step 4 : set PD4 as output for buzzer.
Step 5 : set Port C as input for the sensors.
Step 6 : while (1) (//infinite loop)
Step 6 : button = value from the DTMF output.
Step 8 : if (button 2 )
Move forward command to port B.
Step 9 : if (button 4 )
Move left command to port B.
Step 10 : if (button 5 )
Stop command to port B.
Step 11 : if (button 6 )
Move right command to port B.
Step 12 : if (button 8 )
Move backward command to port B.
Step 13 : if (button 1 )
Move forward command to port B.
Step 14 : if (button 3 )
Move forward command to port B.
Step 15 : if (button 7 )
Move backward command to port B.
Step 16 : if (button 9 )
Move backward command to port B.
Step 17 : right_sensor= right sensor value from port C.
Left_sensor = left sensor value from port C.
Step 18 : if(right_sensor = on and left_sensor= on)
Stop command to port B.
Step 19 : if(right_sensor = off and left_sensor= on)
Stop command to port B.
Step 20 : if(right_sensor = on and left_sensor= off)
Stop command to port B.
Step 21 : temp= analog value from the temperature sensor.
Step 22 : temp= (5.0 * temp * 100.0)/1024.0 (//convert to digital value)
Step 23 : if (temp > 55 )
Buzzer on command to pin PD4.
Step 24 : if (temp<55)
Buzzer off command to pin PD4.
Step 25 : end while loop.

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Result
The final results are the device which can be controlled by the user. It senses the
temperature and when the temperature crosses the threshold the buzzer alarm is
switched on. The device has the freedom of movement to its right, left, forward and
backward. The obstacle in the front of the device is detected and the movement is
stopped. The fig 6, 7 and 8 shows the built device. The result of movement of the
device is tabulated in table 1.
Table 1: Result of Movement Module
Sl no Key press result
1 2 Device moves forward
2 4 Device moves left
3 5 Device stops
4 6 Device moves right
5 8 Device moves backward
6 1 Device moves forward
7 3 Device moves forward
8 7 Device moves backward
9 9 Device moves backward
Figure 6: The top view of the device

Control of The Locomotion of Temperature Sensor 14417
Figure 7: The Front View of The Device
Figure 8: Back View of the Device
Conclusion
The device uses the AVR ATMega8 microcontroller for the control of the device. The
LM35 temperature sensor is used for sensing the temperature. The output is given in
the form of buzzer if the temperature crosses the threshold value. The DTMF module
is used for the communication between the user and the device. The movement is
done by using the geared motors which are connected to the L293D motor driver. The
commands are reveived from the user and the device moves accordingly.The user has
to be in the visible range of the device because the control is given to the user and the
user has to see the movement of the device. Hence, this limitation can be considered
for the future work. The present device senses only the temperature. Addition of other
sensors like the gas sensors, humidity sensor, sound sensor etc can be added to the

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device for better performance. This will improve the usability of the system and it can
be used for more applications.
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