Temperature Controller using Atmega16

1. Temperature Controller Using
FPGA/Microcontroller and
NE555
Presented By:
Siddhant Jaiswal
Animesh Barik
Niraj Raj
Ankit Kumar Nath
In the Guidance of :
Prof. Arindam Biswas
Department of Electrical &
Electronics Engineering
Neotia Institute of Technology
Management And Science

2. Acknowledgement
The 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.

3. Working Model of Temperature Controller

4. Definition of Temperature Controller
Temperature 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.

5. Flow Chart for Temperature Controller
Temperature
Sensing
•The sensors senses
the temperature of
the device
ADC
•The analog
temperature output
signal is converted
to digital signal
•The digital signal is
passed on to
Microcontroller
PWM
•The microcontroller
on receiving the
signal generates the
PWM accordingly
•It also shows the
temperature on the
LCD module
Output
•The PWM output
signal is supplied to
the output devices
via relay switches

6. Block Diagram of Temperature Controller

7. Temperature Controller Using Atmega16
Microcontroller
A temperature Controller can be mainly divided into 3
parts:
The Temperature sensing unit
Processing Unit
Controlled output generating unit

8. The Main Hardware Required
An Atmega16 Microcontroller board (with inbuilt ADC)
LM35 Temperature Sensor
Relay
NE 555
FPGA Board

9. Temperature Sensor
 The LM35 series are precision integrated-circuit
temperature devices with an output voltage
linearly proportional to the Centigrade
temperature.
 Linear + 10-mV/°C Scale Factor
 Rated for Full −55°C to 150°C Range
 Calibrated Directly in Celsius (Centigrade)

10. Atmega16 Microcontroller
 The 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.

11. Analog to Digital Conversion
An 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.

12. ADC in Atmega16
The ADC in Atmega16 is a 10 bit ADC meaning it has
the ability to detect 1,024 (210) discrete analog levels
The ADC reports a ratio metric value. This means that
the ADC assumes 5V is 1023 and anything less than 5V
will be a ratio between 5V and 1023.

𝑅𝑒𝑠𝑜𝑙𝑢𝑡𝑖𝑜𝑛 𝑜𝑓𝐴𝐷𝐶
𝑅𝑒𝑓𝑒𝑟𝑒𝑛𝑐𝑒 𝑉𝑜𝑙𝑡𝑎𝑔𝑒
=
𝐴𝐷𝐶 𝑅𝑒𝑎𝑑𝑖𝑛𝑔
𝐴𝑛𝑎𝑙𝑜𝑔 𝐼𝑛𝑝𝑢𝑡 𝑉𝑜𝑙𝑡𝑎𝑔𝑒

13. LCD Display
 LCD stands for liquid crystal display.
 All the LCD's performs the same functions (display characters
numbers special characters ASCII characters etc.).
 ALL LCDs have
 Eight(8) Data pins
 VCC (Apply 5v here)
 GND (Ground this pin)
 RS (Register select)
 RW (read - write)
 EN (Enable)
 V0 (Set LCD contrast)

14. 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.

15. Duty Cycle
 The 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.

16. 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.

17. Generation of PWM using FPGA
 In 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.

18. Flowchart for PWM

19. Different modes of NE555
 In 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, R2 and C:

20. Internal circuit of NE555

21. Working of NE555
 The 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 flop
 According to the input of the flip flop the out put is given
 Pin no 3 i.e output gives us the pulsating signal (pwm).

22. Working contd…
 When R=0 and S=1 output =1
 When R=1 and S=0 output=0

23. Implementation of Temperature
Controller using NE555

24. Output Waveform acquired Theoretically
For Different Values Of R2

25. Hardware Implementation

26. 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.

27. Limitation of the Temperature Controller
System
We 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 can’t be recognized by the
system.

28. Thank You!!!