HUMIDITY INDICATORHUMIDITY INDICATORAND AND

CONTROLLERCONTROLLER

GROUP MEMBERS : PRINCY ELSA PHILIP

RIA VARGHESE

RESHMA MOHANDAS

RIBIN

ARUN ISAAC

INTRODUCTIONINTRODUCTION

• HUMIDITY IS THE AMOUNT OF WATER CONTENT PRESENT IN THE ATMOSPHERE.

• HUMIDITY INDICATOR AND CONTROLLER IS USED TO DETECT AND CONTROL HUMIDITY MAINLY IN TEXTILE INDUSTRIES.

• IT IS ALSO USED IN CERTAIN FACTORIES TO PROTECT THE HIGHLY SENSITIVE HEAVY DUTY MACHINES FROM DAMAGE DUE TO INCREASED MOISTURE CONTENT IN ITS SURROUNDINGS.

• IT IS VERY SIMPLE TO CONSTRUCT AND USE.

ICIC

• LM3914 IS A MONOLITHIC

INTEGRATED CIRCUITS

THAT SENSES ANALOG VOLTAGE

LEVELS.

• IT DRIVES 10 LEDs ( LED 1

THROUGH LED 7 ) , PROVIDING

A LINEAR ANALOG DISPLAY

• THE IC CONTAINS ITS OWN

ADJUSTABLE REFERENCE AND

ACCURATE 10 STEP VOLTAGE

DIVIDER

• THE LM3914 IS RATED FOR OPERATION FROM 0◦C TO +70◦C.

LEDLED

• LIGHT EMMITTING DIODE.

• USED TO INDICATE THE HUMIDITY LEVELS FROM 30%RH TO 90%RH.

• 8 LEDS ARE USED IN THEIR CIRCUIT.

HUMIDITY SENSOR MODULEHUMIDITY SENSOR MODULE

• HUMIDITY SENSOR SY-HS-220 SENSES HUMIDITY LEVELS.

IT IS BASED ON CAPACITIVE TECHNOLOGY.

• IT CONVERTS THE RH DIRECTLY INTO EQUIVALENT MILLIVOLT

ANALOGUE OUTPUT.

• THE RATED VOLTAGE IS 5V.

• ITS OPERATING TEMPERATURE RANGE IS 0-60◦C AND

HUMIDITY IS 30-90% RH.

• ITS STANDARD OUTPUT AT 25◦C AND 60% RH IS 1980mV DC.

• THE OUTPUT OF THE MODULE IS CONNRCTED TO THE

ANALOGUE INPUT PIN 5 OF LM3914.

RELAYRELAY• A RELAY IS AN ELECTROMECHANICAL DEVICE THAT IS ACTUATED BY AN ELECTRICAL CURENT.

• THEY ARE LIKE REMOTE CONTROL SWITCHES.

• 5V , 1C/O RELAY IS USED.

• RELAY CAN BE TRIGGERED AT THE DESIRED HUMIDITY LEVEL BY CONNECTING THEIR BASES TO THE CORRESPONDING PINS OF IC1.

• RELAY CAN BE USED TO STOP THE CURRENT PROCESS WHEN PREDETERMINED HUMIDITY LEVEL IS REACHED.

CIRCUIT DIAGRAM

WORKINGWORKING• HUMIDITY SENSOR SY-HS-220 SENSES HUMIDITY LEVELS AND SENDS THE SIGNAL TO THE LM3914 IC .

• THE IC ACCEPTS ANALOGUE SIGNALS AT ITS INPUT PIN 5 AND DRIVES 10 LEDs PROVIDING A LINEAR ANALOGUE DISPLAY.

• AT ANY POINT OF TIME , IF ALL LEDs GLOW , IT INDICATES THE HUMIDITY LEVEL IS 90% RH AND IF ONLY LED1 GLOWS, IT INDICATES THATR HUMIDITY IS 30% RH.

• BEFORE USING THIS CIRCUIT HUMIDITY LEVEL IS FIRST CALIBRATED USING PRESET.

• PNP TRANSISTORS T1 AND T2 CONTROL TWO ELECTRICAL

DEVICES THROUGH RELAYS RL1 AND RL2.

• YOU CAN TRIGGER THESE RELAYS AT THE DESIRED HUMIDITY

LEVEL BY CONNECTING THEIR BASES TO THE

CORRESPONDING PINS OF IC1. ALL PINS ARE TERMINATED AT

CON3 FOR EASE OF CONNECTION.

• RL2 CAN BE USED TO STOP THE CURRENT PROCESS WHEN

PREDETERMINED HUMIDITY LEVEL IS REACHED.

THANK YOU