Humidity inicator and controller
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This document describes a humidity indicator and controller circuit that was designed by a group of students. The circuit uses a humidity sensor module to detect humidity levels from 30% to 90% RH. It sends the analog signal to an LM3914 integrated circuit that drives 8 LEDs to provide a visual indication of the humidity level. Relays can be triggered at certain humidity levels to control electrical devices, such as stopping a process when a predetermined humidity level is reached. The circuit provides a simple way to both detect and control humidity levels, especially in industrial applications.
Humidity inicator and controller
- 2. GROUP MEMBERS : PRINCY ELSA PHILIP RIA VARGHESE RESHMA MOHANDAS RIBIN ARUN ISAAC
- 3. 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.
- 4. ICIC
- 5. • 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.
- 6. LEDLED • LIGHT EMMITTING DIODE. • USED TO INDICATE THE HUMIDITY LEVELS FROM 30%RH TO 90%RH. • 8 LEDS ARE USED IN THEIR CIRCUIT.
- 7. HUMIDITY SENSOR MODULEHUMIDITY SENSOR MODULE
- 8. • 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.
- 9. 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.
- 11. CIRCUIT DIAGRAM
- 13. 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.
- 14. • 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.
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