Temperature Controller Using FPGA/Microcontroller and NE555Presented By:Siddhant JaiswalAnimesh BarikNiraj RajAnkit Kumar Nath

In the Guidance of :Prof. Arindam BiswasDepartment of Electrical & Electronics EngineeringNeotia Institute of Technology Management And Science

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AcknowledgementThe success and final outcome of this project required a lot of guidance and assistance from many people and we are extremely fortunate to have got this all along the completion of our project work. Whatever we have done is only due to such guidance and assistance and we would not forget to thank them. I respect and thank Mr. Arindam Biswas, for giving us an opportunity to work on this project and providing us all support and guidance which made us complete the project on time. We are extremely grateful to him for providing such a nice support and guidance though he had a busy schedule.

Working Model of Temperature Controller

Definition of Temperature ControllerTemperature control is a process in which change of temperature of a space (and objects collectively there within) is measured or otherwise detected, and the passage of heat energy into or out of the space is adjusted to achieve a desired average temperature.

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Flow Chart for Temperature Controller

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Block Diagram of Temperature Controller

Temperature Controller Using Atmega16 MicrocontrollerA temperature Controller can be mainly divided into 3 parts:The Temperature sensing unitProcessing UnitControlled output generating unit

The Main Hardware RequiredAn Atmega16 Microcontroller board (with inbuilt ADC)LM35 Temperature SensorRelayNE 555FPGA Board

Temperature SensorThe LM35 series are precision integrated-circuit temperature devices with an output voltage linearly proportional to the Centigrade temperature.Linear + 10-mV/C Scale FactorRated for Full 55C to 150C RangeCalibrated Directly in Celsius (Centigrade)

Atmega16 MicrocontrollerThe ATmega16 is a low-power CMOS 8-bit microcontroller based on the AVR enhanced RISC architecture. By executing powerful instructions in a single clock cycle, the ATmega16 achieves throughputs approaching 1 MIPS per MHz allowing the system designer to optimize power consumption versus processing speed.

Analog to Digital ConversionAn Analog to Digital Converter (ADC) is a very useful feature that converts an analog voltage on a pin to a digital number. By converting from the analog world to the digital world, we can begin to use electronics to interface to the analog world around us.

ADC in Atmega16

LCD DisplayLCD stands for liquid crystal display. All the LCD's performs the same functions (display characters numbers special charactersASCIIcharacters etc.).ALL LCDs haveEight(8) Data pinsVCC (Apply 5v here)GND (Ground this pin)RS (Register select)RW (read - write)EN (Enable)V0 (Set LCD contrast)

What is PWM ?Pulse-width modulation (PWM), or pulse-duration modulation (PDM), is a modulation technique used to encode a message into a pulsing signal. The main use of PWM is to allow the control of the power supplied to electrical devices, especially to inertial loads such as motors.

Duty CycleThe term duty cycle describes the proportion of 'on' time to the regular interval or 'period' of time. A low duty cycle corresponds to low power, because the power is off for most of the time. Duty cycle is expressed in percent, 100% being fully on.

How PWM works ? PWM output signals are constructed by comparing two control signals, a carrier signal and a modulation signal. The carrier signal is a high frequency (switching frequency) triangular waveform. The modulation signal can be any shape. If the peak of the modulation is less than the peak of the carrier signal, the output will follow the shape of the modulation signal.

Generation of PWM using FPGAIn FPGA we are generating PWM signal using 4 bit counter as modulating signal and the temperature sensor output is the input signal along with a clock. At the positive edge of the clock our counter is incremented and we compare the counter to the sensor output to generate PWM signal. If the value of counter is less than sensor output then my PWM signal is 0 or OFF and when the counter value is greater than sensor output the PWM signal is 1 or ON. The total time period of PWM is 15 clock pulses.

Flowchart for PWM

Different modes of NE555In astable mode, the 555 timer puts out a continuous stream of rectangular pulses having a specified frequency. The astable configuration, with two resistors, cannot produce a 50% duty cycle.In the astable mode, the frequency of the pulse stream depends on the values of R1, R2and C:

Internal circuit of NE555

Working of NE555The 555 uses two comparators, comparing Voltage against 1/3 and 2/3 of Vcc to determine whether to flip the output state.It has two comparators which compare the voltage and sends the output value to flip flopAccording to the input of the flip flop the out put is givenPin no 3 i.e output gives us the pulsating signal (pwm).

Working contdWhen R=0 and S=1 output =1When R=1 and S=0 output=0

Implementation of Temperature Controller using NE555

Output Waveform acquired Theoretically For Different Values Of R2

Hardware Implementation

How is the concept used in the Temperature Controller?

The Resistance which on changing changes the output can be interchanged with any Temperature Sensors. Which will lead to our Temperature controlling.

Limitation of the Temperature Controller SystemWe just conceptually say that huge no. of peripheral devices must be connected through the two port, but at the time of implementation of the project we are not able to connect all possible devices with the microprocessor port.The sensibility of the system is 0.20C,so any change in temperature less than that cant be recognized by the system.

Thank You!!!

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