Thermo-electric (TE) technology is used in both electricity generation and air-conditioning. The Thermo-electric coolers(TEC) uses Peltier effect which converts the electrical energy applied from the ends of the Thermo-electric module into the temperature difference. The main objective of the work is to design a highly reliable and wearable jacket that controls extreme temperatures say working in thermal power plants, within the jacket. The extreme temperatures can be monitored using temperature sensors placed on both sides of the Thermo-electric cooler module and controlled using ARM LPC2148 Microcontroller. In Industries, this jacket provides a more practical and safer solutions for human working under extreme temperatures. Furthermore, this jacket can also be applied as a good warmer one for human beings working in cold regions(say Polar regions).

1. INTERNATIONAL JOURNAL FOR TRENDS IN ENGINEERING & TECHNOLOGY
VOLUME 4 ISSUE 2 – APRIL 2015 - ISSN: 2349 - 9303
116
ARM Based Climate Controlled Wearable Jacket
R.Naghalakshimi Dr. S. Jayanthy
II year Student, M.E. Embedded Systems Technologies Professor, Department of ECE
Sri Ramakrishna Engineering College Sri Ramakrishna Engineering College
Coimbatore, India Coimbatore, India
nagramval@gmail.com sjayanthyabi@gmail.com
Abstract— Thermo-electric (TE) technology is used in both electricity generation and air-conditioning. The Thermo-electric
coolers(TEC) uses Peltier effect which converts the electrical energy applied from the ends of the Thermo-electric module into the
temperature difference. The main objective of the work is to design a highly reliable and wearable jacket that controls extreme
temperatures say working in thermal power plants, within the jacket. The extreme temperatures can be monitored using
temperature sensors placed on both sides of the Thermo-electric cooler module and controlled using ARM LPC2148
Microcontroller. In Industries, this jacket provides a more practical and safer solutions for human working under extreme
temperatures. Furthermore, this jacket can also be applied as a good warmer one for human beings working in cold regions(say
Polar regions).
Index Terms— ARM7 LPC2148 Microcontroller, Heat dissipation, Monitoring and Controlling Temperatures, Peltier effect,
Temperature Sensor, Thermo-electric Cooler (TEC) Module, Wearable Jacket.
——————————  ——————————
1 INTRODUCTION
Thermo-electric cooling is a way to remove thermal energy from a
medium, device or component by applying a voltage of constant
polarity to a junction between dissimilar electrical conductors or
semiconductors. A thermo-electric cooling system typically employs
a matrix of semiconductor pellets sandwiched in between two large
electrodes. When a DC voltage source is connected between the
electrodes, the negatively-charged side becomes cooler while the
positively-charged side becomes warmer [3]. The negative electrode
is placed in contact with the component, device or medium to be
cooled, while the positive electrode is connected to a heat sink that
radiates or dissipates thermal energy into the external environment.
A Peltier cooler can also be used as a thermo-electric generator.
When operated as a cooler, a voltage is applied across the device,
and as a result, a difference in temperature will build up between the
two sides ( the Peltier effect). When operated as a generator, one side
of the device is heated to a temperature greater than the other side,
and as a result, a difference in voltage will build up between the two
sides (the Seebeck effect).
A single-stage Thermo-electric cooler will typically produce a
maximum temperature difference of 70 °C between its hot and cold
sides. The more heat moved using a TEC Module, the less efficient it
becomes, because the TEC Module needs to dissipate both the heat
being moved, as well as the heat it generates itself from its own
power consumption. The amount of heat that can be absorbed is
proportional to the current and time [1].
In general, thermo-electric cooling is less efficient than
compressor-based refrigeration. However, in situations where
thermal energy must be transferred away from a solid or liquid on a
small scale, a thermo-electric cooling may be more practical and
cost-effective than a conventional refrigeration system [2]. Other
advantages of the thermo-electric cooling include minimized cost,
power consumption, portability, long operating life and minimal
maintenance requirements.
Thermo-electric cooling is used in electronic systems and
computers to cool sensitive components such as power amplifiers
and microprocessors. The technology can also be useful in a satellite
or space probe to moderate the extreme temperatures that occur in
components on the sunlit side and to warm the components on the
dark side [4].
So, Thermo-electric cooler modules can be implemented in the
design of climate controlled wearable jacket which helps people
working in extreme temperatures. The extreme temperatures can be
monitored using temperature sensors placed at the top and bottom
the thermo-electric cooler module and controlled using ARM7
LPC2148 Microcontroller embedded with the module.
In order to control the heat dissipated at the hot side of the Thermo-
electric cooler module, a small liquid pump and heat sink can be
connected using Relay. To control the extreme temperatures and
provide a temperature that is tolerable to people, a relay is connected
to control the power supply of the Thermo-electric cooler module.
Hence, the Thermo-electric cooler module makes an effective climate
controlled wearable jacket which provides a more safer and practical
solutions to people working in extreme temperatures. This module
makes the design very cheap and reliable. The Climate Controlled
Wearable jacket is implemented in a single system using a Thermo-
electric cooler module along with a heat sink prototype. In this paper,
Section II describes about the proposed Climate Controlled wearable
jacket, system design, Programming in IDE, Thermo-electric cooler
Module and Software algorithm. Section III displays the proposed
system design. Section IV explains the various experimental results
took at various instances. Finally, Section V deals with the conclusion
and future work.
2 PROPOSED CLIMATE CONTROLLED WEARABLE
JACKET
2.1 Existing System
Currently, the Thermo-electric cooler modules are used in designing

2. INTERNATIONAL JOURNAL FOR TRENDS IN ENGINEERING & TECHNOLOGY
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cooling products for custom/OEM applications, telecommunications,
consumer electronics and cold plates for laboratories [5]. They are
used in scientific applications, digital cameras and charge coupled
devices(CCD) to minimize thermal noise and optimize sensitivity.
Also, the heat dissipated in thermo-electric module made it less
efficient. Further, it caused more power consumption. So, the
Thermo-electric module is incorporated with the heat sink and liquid
pump for proper heat dissipation thus controlling extreme
temperatures to tolerable temperatures for people who wear it. The
main advantage of the climate controlled wearable jacket is that the
system design is less complex, easily controllable, long life, reliable,
consumes less power, small in size and weight and it provides more
affordable and needful solutions to people.
2.2 System Design
The system consists of two temperature sensors placed at the top and
bottom of the Thermo-electric cooler module. Two different
temperature values are monitored by the two temperature sensors
which are connected to the ADC port of the ARM7 LPC2148
Microcontroller. For visual inspections, these values are displayed in
the LCD. In order to control the heat dissipated at the hot side of the
Thermo-electric cooler module, a small liquid pump and heat sink is
connected to the Microcontroller using Relay. The block diagram of
the system is shown in the Fig 1. To control the extreme temperatures
and provide a temperature that is tolerable to people, another relay is
connected to control the supply of power to the Thermo-electric
cooler module.
Fig. 1. Block Diagram of Climate Controlled Wearable Jacket
2.3 Programming in the KEIL IDE
The Keil µVision IDE is a simple integrated development
environment (IDE) that runs on regular personal computers and
provides toolsets for a powerful, easy to use and easy to learn
environment for developing embedded applications. It include the
components we need to create, debug and assemble our C/C++
source files, and incorporate simulation for microcontrollers and
related peripherals. It also have RTX RTOS Kernel Library, Device
Database, Debugger and Analysis tools and complete device
simulation. It also has RTOS and Middleware components for
implementing time-critical softwares and shorten the development
cycle. Further, it has Flash File system, USB Device Interface and
CAN Interface. The Keil ULINK-JTAG family of adapters connect
the USB port of a PC to the target hardware. This enables us to
download, test and debug the final executable hex code generated
from the Keil IDE to the target hardware.
Since ARM7 LPC2148 Microcontroller Board is used in this
system, which is more employed in industrial automation and
consumer electronics, it has capability to consume less power and
work with more efficiency. It is very easy to program in the Keil
µVision IDE because IDE has inbuilt libraries for individual
components, Middleware toolchain, etc. Since this system fully deals
with monitoring and controlling the Thermo-electric cooler module
and provide necessary controlled power supply to it, the
Microcontroller unit is programmed using the Keil IDE.
The temperature values are monitored via ADC port of the
Microcontroller through which the temperature sensors are
connected. For visual inspections, these values are displayed in the
LCD. The Thermo-electric cooler module is controlled by using
Relay which is connected to the Microcontroller. To achieve the
system monitoring and controlling architecture, we should include
the library files for initializing the LCD and clock frequency. The
initialization, programming, debugging, simulation and downloading
to the target Microcontroller, all can be done using the Keil µVision
IDE and corresponding Keil ULINK-JTAG adapter. The Keil
µVision IDE programming environment is mentioned in Fig 2.
Fig. 2. Programming in Keil µVision IDE
2.4 Thermo-electric cooler Module
Thermo-electric cooling uses the Peltier effect to create a heat flux
between the junction of two different types of materials. A Peltier
cooler, heater, or thermo-electric heat pump is a solid-state
active heat pump which transfers heat from one side of the device to
the other, with consumption of electrical energy, depending on the
direction of the current. Such an instrument is also called a Peltier
device, Peltier heat pump, solid state refrigerator, or thermo-electric
cooler (TEC) as shown in the Fig 3. It can be used either for heating
or for cooling, although in practice the main application is cooling. It
can also be used as a temperature controller that either heats or cools.
A Thermo-electric cooler module consist of two unique
semiconductors, one n-type and one p-type, because they need to
have different electron densities. The semiconductors are placed

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thermally in parallel to each other and electrically in series and then
joined with a thermally conducting plate on each side.
Fig. 3. Thermo-electric Cooler (TEC) Module
When a voltage is applied to the free ends of the two
semiconductors there is a flow of DC current across the junction of
the semiconductors causing a temperature difference. The side with
the cooling plate absorbs heat, which is then moved to the other side
end of the device where the heat sink is. Thermo-electric coolers are
typically connected side by side and sandwiched between two
ceramic plates. The cooling ability of the total unit is then
proportional to the number of Thermo-electric coolers in it.
2.5 Software Algorithm
The system is programmed in such a way that the temperature
sensors monitor the temperature values, input the values to the
Microcontroller via ADC port and the values are displayed in the
LCD for visual inspections. In order to control the heat dissipated at
the hot side of the Thermo-electric cooler module, a small liquid pump
and heat sink are placed on it and connected to the Microcontroller
using Relay. To control the extreme temperatures and provide a
temperature that is tolerable to people, another relay is connected to
control the supply of power to the Thermo-electric cooler module. The
algorithm for such system is as follows.
ALGORITHM
Step 1: Include header files for Interfacing the LCD with the
Microcontroller unit.
Step 2: Initialize VPBDIV register as 0x02 for setting clock
frequency of 30 MHz.
Step 3: Initialize Analog ports for interfacing two temperatures to
measure two different temperature readings of Thermo-electric
Module.
Step 4: Initialize ports for the LCD operating in 4-bit Mode.
Step 5: Initialize ports for a relay that controls liquid pump and the
heat sink, and another relay that controls Thermo-electric module.
Step 6: Begin the infinite while loop, read the Temperature values
from sensors in ADC port and display the values in the LCD.
Step 7: Initially, Thermo-electric Cooler Module will start cooling
from Normal temperature. So, both the relays will be ON.
Step 8: Thermo-electric cooler Module starts cooling and when the
Temperature goes below 20°C, relay that controls pump gets tripped
OFF. But Thermo-electric cooler Module still cools since the relay
that controls it, is ON.
Step 9: When the Temperature goes below 16°C, relay that controls
Thermo-electric cooler module also gets tripped OFF. Now,
Thermoelecric cooler module gets heated up to Normal temperature
say 25°C. When the temperature goes above 23°C, both the relay
gets turned ON and loop back to step 6.
3 PROPOSED SYSTEM DESIGN
The Climate Controlled Wearable Jacket consist of Thermo-electric
Cooler module interfaced with the ARM7 LPC2148 Microcontroller
as shown in Fig 4. This system consists of two temperature sensors
placed at the top and bottom of the Thermo-electric cooler module.
Two different temperature values are monitored by the two
temperature sensors which are connected to the ADC port of the
ARM7 LPC2148 Microcontroller. For visual inspections, these
values are displayed in the LCD. In order to control the heat
dissipated at the hot side of the Thermo-electric cooler module, a small
liquid pump and heat sink are placed on it and connected to the
Microcontroller using Relay. To control the extreme temperatures and
provide a temperature that is tolerable to people, another relay is
connected to control the supply of power to the Thermo-electric
cooler module.
Fig. 4. Climate Controlled Wearable Jacket
4 EXPERIMENTAL RESULTS
Initially, Thermo-electric Cooler Module will start cooling from
Normal temperature. So, both the relays will be ON. The two
different temperature readings are displayed in the LCD as shown in
Fig 5.Thermo-electric cooler Module starts cooling and when
Temperature goes below 20°C, Pump control relay gets tripped OFF.
But Thermo-electric cooler Module still cools since the relay that
controls it, is in ON condition. When Temperature goes below 16°C
which is intolerable for human, Thermo-electric cooler module
control relay also gets tripped OFF.

4. INTERNATIONAL JOURNAL FOR TRENDS IN ENGINEERING & TECHNOLOGY
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Fig. 5. Different Temperature values displayed in LCD
Now, Thermoelecric cooler module gets heated up to Normal
temperature say 25°C. When temperature goes above 23°C, both the
relay gets turned ON.
The observations are being made for the climate controlled
wearable jacket for different conditions and the values are being
tabulated as shown in the Table 1. From the table, it is inferred that
when Temperature goes below 20°C, Pump control relay gets tripped
OFF. But Thermo-electric cooler Module still cools since the relay
that controls it, is in ON condition.
TABLE 1
OBSERVATIONS MADE AT VARIOUS INSTANCES
Temperature
at Cold Side
(°C)
Temperature
at Hot Side
(°C)
Pump
Control
Relay
Status
(ON/
OFF)
Thermo-electric
Cooler Module
Control Relay
Status
(ON/OFF)
25.4 27.7 ON ON
23.8 27.9 ON ON
21.3 28.2 ON ON
19.8 28.5 OFF ON
17.6 29.1 OFF ON
16.4 29.2 OFF ON
15.9 29.7 OFF OFF
16.7 29.2 OFF OFF
18.6 28.8 OFF OFF
21.2 28.1 OFF OFF
22.8 28.0 OFF OFF
23.1 27.4 ON ON
22.9 28.0 ON ON
21.6 28.5 ON ON
19.4 28.3 OFF ON
When Temperature goes below 16°C which is intolerable
for human, Thermo-electric cooler module control relay also gets
tripped OFF. Then, Thermoelecric cooler module gets heated up to
Normal temperature say 25°C. When temperature goes above 23°C,
both the relay gets turned ON.
5 CONCLUSION
Thus the climate controlled wearable jacket monitors the extreme
temperatures, controls and provides tolerable temperature to the
people who wear it using Thermo-electric cooler Module. The heat
dissipated in this system is controlled at a maximum rate using a heat
sink and a liquid pump. Thus the system eliminates the conventional
methods of handling heat dissipation. The Ultra thin Thermo-electric
Cooler Module provides more afforable and needful solutions to the
people making the system less complex, very less power
consumption, small in size and weight.
As Thermo-electric Cooler Module works in Peltier Cooling
Effect, the system can be implemented in wearable jacket that can
provide tolerable and controlled temperature to the people wearing it.
In the Future, if the system is implemented in thin fabric designed
jacket, this system would be a milestone in the field of Wearable
Electronics for sure. The work can also be extended by using
increased figure of merit Peltier Modules and efficient heat exchange
technology.
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