This document describes an RF-based transformer temperature monitoring system. The system uses a temperature sensor interfaced with a microcontroller to monitor and display the temperature on an LCD. The temperature is also transmitted via RF to a remote receiver connected to a PC. Key components include a temperature sensor, microcontroller, LCD, RF transmitter and receiver modules. The system is powered by a voltage regulator and programmed using the Arduino IDE.
2. INTRODUCTION
ď˘ Project dealing with monitoring through RF and data log on the PC at
remote location
ď˘ Has proper interface on temperature sensor according to the need.
ď˘ The temperature variation is monitored with proper resolution.
ď˘ The system consists of a temperature sensor, Advance controller
microcontroller ATMEGA168,RF modules, UART communication
(controller and PC)and the LCD.
ď˘ This all system will be interfaced together to design the complete
module
ď˘ The temperature level is continuously monitored by the
microcontroller.
ď˘ The controller gives proper output to control the LCD and UART
communication between controller and PC
3. PROJECT SCOPE
ď Understanding of monitoring systems
ď Understanding temperature sensor and its interface
ď Understanding of LCD interfacing.
ď Understanding of âEmbedded systemâ
ď Understanding the use of Microcontroller and programming in C
language.
ď Understanding UART communication and programming
ď Understanding RF and interface.
ď PCB designing and Circuit designing.
ď PCB development, Component mounting and soldering.
ď Testing of the circuit.
5. WORKING IN BRIEF
1. The temperature sensor will continuously monitor the
temperature of the transformer
2. The temperature sensor will be connected to the controller
to give the signal to detect the temperature
3. The temperature will be displayed on the LCD connected to
the controller
4. This temperature value will be transferred over the RF
channel to the remote location.
5. The receiver will receive the value which is sent through the
microcontroller to the PC.
9. COMPONENTS
ď˘ DS18B20 temperature sensor
ď˘ LCD
ď˘ MICROCONTROLLER ATMEGA 168
ď˘ BRIDGE RECTIFIRE
ď˘ 7805 IC
ď˘ CAPACITORS, RESISTORS, OSCILLATORS
ď˘ RF transmitter and receiver
10. DS18B20 TEMPERATURE SENSOR
ď˘ The DS18B20 digital thermometer provides 9-bit to 12-bit
Celsius temperature measurements.
ď˘ The DS18B20 communicates over a 1-Wire bus that by
definition requires only one data line (and ground) for
communication with a central microcontroller.
ď˘ Each DS18B20 has a unique 64-bit serial code, which allows
multiple DS18B20s to function on the same 1-Wire bus
ď˘ Converts Temperature to 12-Bit Digital Word in 750ms (Max)
11. LCD (LIQUID CRYSTAL DISPLAY)
ď˘ Is an electronic display module.
ď˘ 16x2 LCD display is very basic module and is very commonly
used in various devices and circuits.
ď˘ 16x2 LCD means it can display 16 characters per line and there
are 2 such lines.
ď˘ Has two registers namely, Command and Data.
ď˘ The command register stores the command instructions.
ď˘ The data register stores the data to be displayed on the LCD.
ď˘ The data is the ASCII value of the character to be displayed on
the LCD.
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LCD (LIQUID CRYSTAL DISPLAY)
ď˘ Need only 6 pins to interface an LCD.
ď˘ D4-D7 is the data pins connection and Enable and Register
select are for LCD control pins. We are not using Read/Write
(RW) Pin of the LCD, as we are only writing on the LCD so we
have made it grounded permanently. If you want to use it,
then you may connect it on your controller but that will only
increase another pin and does not make any big difference.
Potentiometer RV1 is used to control the LCD contrast. The
unwanted data pins of LCD i.e. D0-D3 are connected to ground
13. MICROCONTROLLER
ď˘ Mini computer with necessary support chips on-board.
ď˘ Designed to perform applications where the relationship of
input and output is defined
ď˘ With advancement various features have been included in
the micro-controllers
ď˘ Three main building blocks â system should have to perform
any task.
⢠A processing unit (CPU)
⢠I/O PORTS for interaction with user or physical environment
⢠Memory elements (RAM/ROM/Flash/EEPROM)
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ATMEGA168
ď˘ This is digital as well as analog controller . This controller can
handle input /output of following type.
ď˘ 4K/8K/16K bytes of In-System Programmable Flash with
Read-While-Write capabilities
ď˘ 256/512/512 bytes EEPROM, 512/1K/1K bytes SRAM
INPUT OUTPUT
Digital input Digital output
Analog input Analog output
Digital input Analog output
Analog input Digital output
15. ATMEGA168
ď˘ 23 general purpose I/O lines
ď˘ A 6-channel 10-bit ADC (analog input)
ď˘ 6 output PWM channels(analog output)
ď˘ A serial programmable USART
ď˘ This allows very fast start-up combined with low power
consumption
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ATMEGA168
ď˘ Pin mapping: It is 28 pin DIP IC
ď˘ Requires 16 MHz crystal oscillator
ď˘ AREF is to adjust resolution for
analog monitoring
ď˘ Other pins are configured as per
the need of circuit interface
17. 7805 VOLTAGE REGULATORS
ď˘ A voltage regulator is designed to automatically maintain a
constant voltage level
ď˘ Voltage regulator ICs are available with fixed voltage
(typically 5, 12 and 15V) or variable output voltages
ď˘ For ICs within the 78xx family, the xx is replaced with two
digits, indicating the output voltage (for example, the 7805
has a 5 volt output, while the 7812 produces 12 volts)
18. DIODE BRIDGE
ď˘ A diode bridge is an arrangement of four (or more) diodes in
a bridge circuit configuration that provides the
same polarity of output for either polarity of input
ď˘ When used in its most common application, for conversion of
an alternating current (AC) input into a direct current (DC)
output, it is known as a bridge rectifier
19. CAPACITORS
ď˘ To store electricity, or electrical energy.
ď˘ Also functions as filter, passing AC, and blocking DC.
ď˘ Apply DC voltage- electric charge is stored on each electrode.
ď˘ Three types of capacitor i.e. ceramic capacitor & electrolytic
capacitor and variable.
ď˘ Polarized capacitors - Electrolytic
ď˘ Un-Polarized capacitors â ceramic
ď˘ Variable capacitors
20. RESISTOR
ď˘ A resistor is a device found in circuits that has a certain
amount of resistance. Why would you ever want to add
resistance to a circuit by using a resistor?
ď˘ The most common reason is that we need to be able to
adjust the current flowing through a particular part of the
circuit.
ď˘ If voltage is constant, then we can change the resistor to
change the current. I=V /R If âVâ is constant and we change
âRâ, âIâ will be different.
ď˘ So for a constant voltage it limits the current
21. CRYSTAL OSCILLATOR
ď˘ A crystal oscillator is an electronic circuit that produces
electrical oscillations at a particular designed frequency
determined by the physical characteristics of one or
more crystals, generally of quartz, positioned in the
circuit feedback loop
ď˘ A piezoelectric effect causes a crystal such as quartz to
vibrate and resonate at a particular frequency