Smart Digital Thermometer

8/13/2019 Smart Digital Thermometer

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SUTEN NAIDU & PAV

ENGINEERING SYST

DESIGN

MR. MANICKAM

SMART

DIGITAL

THERMOME

MINI PROJECT REVIEW


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PROBLEM STATEMENT

The main intention of this project is to build and implementthermometer that will be able to measure the sur

temperature, for example the temperature of a room and to

user if the temperature is higher than the desired temperature


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WHAT IS DIGITAL THERMOMETER?

Digital thermometers are gadgets that are used for m

temperature. They are generally easier to read than the traditio

of thermometer, and they are more accurate too. Instead of

digital thermometers have built in sensors


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DIGITAL THERMOMETER VS MERCURYTHERMOMETER

When talking about delivering accurate readings (figuresthermometers are more accurate when compared against

thermometers, since the interpretation of digital thermometer

doesntrequire eye straining in an effort to focus on the ana

bars typically found on mercury thermometers.


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To show the accurate surrounding temperature on the LCD

Extra features:

Light indicator to show the temperature staGreen light-temperature normal, Yellow- m

Red-temperature high) Alarm to warn the surrounding people

temperature is higher than desired temperat

DESIGN DESCRIPTION


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MC

DISPLAYTEMPERATURE

SENSOR

BUZZERLIGHT

INDICATOR


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COMPONENTS PIC 16F877A microcontroller.

LM35 temperature sensor.

LM7805 5V voltage regulator.

16x2 LCD.

9V battery.

Resistors: 10K (Fixed and variable), 100 (3 units), 18 (1 unit).

Capacitors: 104F and 33pF (2 units).

8MHz crystal oscillator.

3 LEDs (Green, Yellow, Red)

Connecting wires.

Breadboard.

PIC Kit 2.


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PIC16F877A

Peripheral Interface Controller


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8MHZ CRYSTAL OSCILLATOR

Standard frequency crystals - use these crystals to provide a clock in

your microprocessor.

Since the PIC16F877A doesnt have build in oscillator the 8MHz crys

oscillator is used. Rated at 20pF capacitance and +/- 50ppm stability.

A crystal oscillator is an electronic oscillator circuit that uses the mech

resonance of a vibrating crystal of piezoelectric material to create an signal with a very precise frequency.

This frequency is commonly used to keep track of time, to provide a s

clock signal for digital integrated circuits


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WHY LM35 TEMPERATURE SENSOR

LM35 is a precision IC temperature sensor with its output pto the temperature (in C).

The sensor circuitry is sealed and not subject to oxidation, e

The LM35 generates a higher output voltage than thermocomay not require that the output voltage be amplified.

The operating temperature range is from -55C to 150C


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OTHER TEMPERATURE SENSORSAVAILABLE IN MARKET

LM335A - reading range from 40C to 100C.

- gives reading in kelvin

TMP36 - reading range from 50C to 125C.

LM34 - same as LM35, but the reading is in Fahrenhe


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SCHEMATIC


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Documents

Smart Digital Thermometer