An approach for the design of an automatic hand sanitizing machine using fog sanitizer

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 10 Issue: 03 | Mar 2023 www.irjet.net p-ISSN: 2395-0072
© 2023, IRJET | Impact Factor value: 8.226 | ISO 9001:2008 Certified Journal | Page 310
An approach for the design of an automatic hand sanitizing machine
using fog sanitizer
Hridhya AP1
1Department of Biomedical Engineering, EKNM Government polytechnic College, Thrikaripur, Kerala, India
---------------------------------------------------------------------***---------------------------------------------------------------------
Abstract - Since the onset of the COVID-19 pandemic, it is
recommended to wash or sanitize ther hands several times a
day. Also, there should not be much wastage of water or
sanitizer. The scarcity of water pose more problems and
excessive use of hand sanitizer can lead to dryness, cracks,
redness or discoloration on skin and its flaking. It dangerous
if it is ingested or gets into the eyes. To solve this problem, a
system can be developed that allows to sanitize the hands
without using more than 95% sanitizer. To disinfect with
disinfectant or sanitizer, it should reach every millimeter of
the hand. The machine designed is a fog-based system.
When the user inserts the hands inside the box, the mist
system activates automatically, converting the sanitizer into
fog. After exposing the user to sanitizer mist for 5-15
seconds, the hands will be clean.
Key Words: Pandemic, sanitization, fog, humidifier,
Arduino-uno, Covid-19
1. INTRODUCTION
The project is fighting the coronavirus pandemic by
regularly washing hands and keeping public areas clean,
considering the useless access to sanitizer caused by
regular hand washing and control measures. When the
user's hand is placed in the specified position on the
machine, the sensor is activated and the mist system is
automatically activated, turning the sanitizer in the
container into fog. The mist maker module works on the
principle of piezoelectric effect. When a voltage is given to
the crystal, it vibrates at high frequency and turns the
sanitizer into a thick cloud of fog. The system is based on
Arduino Uno R3 microcontroller board Dry Fogging is a
relatively new disinfection method that uses liquid
disinfectants. Since the droplets are in the form of ultra-
fine dry mist, it prevent the chamber from falling easily
onto the surface. Thus this provides a desirable quality for
a disinfection chamber. This fog hand sanitizer can be used
when widely. In densely populated cities and metropolitan
areas, there are several public spaces such as hospitals,
shopping malls, and theatre toilets in trains and airports.
This system ensures proper sanitation and effective
management of water consumption, while saving about
95%. Fog sanitizer can be used to wash your hands and
maintain a non-contact environment. It also helps prevent
the spread of the virus by allowing multiple people to have
access to these affected public sanitizer bottles.
1.1 EXISTING SYSTEM
In the present system, in addition to the manually
controllable sanitizer dispenser, the automatic sanitizer
dispensers are widespread. In a manually controlled
sanitizer dispenser, there will be a direct contact with the
dispenser which causes the spread of viruses or pathogens
from one person to another. In the automatic sanitizer
dispenser, the amount of sanitizer dispensed is over in
quantity, so there will be a wastage of sanitizer and the
over amount of sanitizer used several times will cause
irritation and dry, cracked skin as well as redness or
discoloration, and flaking.
1.2 PROPOSED SYSTEM
In the proposed system, the machine is integrated with a
tank below it. The tank is filled with sanitizer. When the
user inserts hands into the system, this automatically
triggers a fog maker system that converts water in the tank
to fog. The fog will reach all corners of the hand in less than
5 seconds as it is in gaseous state (water vapor). After 5- 15
seconds of sanitizer fog exposure the user's hand is free of
any pathogens. This requires less than 95% of sanitizer and
there is no direct contact with the system. The main
advantage of the system is it delivers only standardized
amounts of sanitizer which will reduce the wastage of
sanitizer. UV LEDs are also installed in the system that has
an ability to kill bacteria, viruses, mold, and fungi. It is a
completely automatic system.
2. HARDWARE
The main hardware includes
1. Fog maker/ultrasonic humidifier
2. Arduino uno R3
3. 5v relay modules
4. Buck converter
5. SD card module
6. Ultrasonic sensor
7. I2C LCD display
8. The PAM8403 amplifier
9. UV led
10. SMPS adaptor

2.1 Fog maker/ultrasonic humidifier
The ultrasonic humidifiers power circuit board with
Atomizing Chip Moisture Film Humidification atomization
machine is suitable for the atomization plate tablet with a
diameter of 20mm. The principle of working of the
ultrasonic Humidifier Piezoelectric Transmitter module is
cavitation produced by sound waves. By providing a DC of
3-12V it will turn into a mini ultrasonic atomizer. The
sound waves contain compression and rarefaction and due
to extremely rapid movement, water droplets cannot
sustain in their liquid state and get converted into vapor
immediately. This vibration is produced by a piezoelectric
filament. Piezoelectric transducer dipped in a water. When
powered it vibrates according to the high frequency,
electronic signal and produces mechanical oscillation.
When the oscillation speed is increased to a high level then
the water particles cannot follow the oscillating surface,
and a momentary vacuum and strong compression occur. It
results in the formation of explosive air bubbles
(cavitation). At cavitation, broken capillary waves are
generated. Tiny droplets of dimension 1-micron diameter
break on the surface tension of the water and are quickly
dissipated into the air. It then converted into vapor form
and absorbed is into the air stream
Fig-1: Ultrasonic Humidifier
2.2 Arduino uno R3
Arduino is an open-source hardware and software
company. Its hardware products are licensed under a CC-
BY-SA license and software is licensed under the GNU
Lesser General Public License (LGPL) or the GNU General
Public License (GPL).
The Arduino Uno R3 is a microcontroller board is a
removable, dual-inline-package IC from ATmega328 AVR
microcontroller. There are 20 digital IO pins (among which
6 can be used as PWM outputs and 6 pins can be used as
analog inputs). It is possible to load the programs onto it
from the easy-to-use Arduino computer program.
2.3 5v Relay modules
A power relay module can be considered as an electrical
switch that is operated by an electromagnet. The
electromagnet in the module is activated by a separate low-
power signal from a microcontroller. When the
electromagnet is activated, it will pull itself to either open
or close an electrical circuit.
Fig-2: 5v Relay Pin Configuration
2.4 Buck converter
A buck converter (step-down converter) is a DC-to-DC
power converter which steps down This module has
onboard constant voltage and constant current control
feature which is useful for general purpose power supply.
There are two multi turn trim pots to adjust the output
voltage and output current. Further, there are three LED
indicators – the first one near the input connector is the
constant-current (cc) indicator, while the next two LEDs
are intended mainly for battery charging applications. By
slowly turning the voltage adjustment trim pot clockwise
direction will raise the output voltage gradually, and a
counter clockwise rotation will lower it. Similarly for the
current.
Fig-3: Buck Converter

2.5 SD card module
An SD Card Module or a Micro SD Card Adapter is a device
which allows connection between a Micro SD card and a
Microcontroller like Arduino.
2.6 Ultrasonic sensor
Fig-4: Pins Of Ultrasonic Sensor
An ultrasonic sensor is an electronic device that can
measure the distance of a target object by emitting
ultrasonic sound waves. It will convert the reflected sound
into an electrical signal. There are two main components in
ultrasonic sensors They are the transmitter that emits the
sound using piezoelectric crystals and the receiver which
receives the sound after it has traveled to and from the
target.
2.7 I2C LCD display
The I2C 16x2 Arduino LCD Screen uses an I2C
communication interface. It can display 16×2 characters on
2 lines, white characters on a blue background. This display
overcomes the drawback of LCD 1602 Parallel LCD Display
in which there is a wastage about 8 Pins on the Arduino for
the display to get working.
Fig-6: I2c Lcd Display Pinout
2.8 The PAM8403 amplifier
It is a dual-channel stereo amplifier that can produces 6W
output. It has inbuilt short circuit protection. this IC itself
does not require any kind of heat sink. It can directly drive
4Ω or 8Ω speakers. A proper speaker with not more than a
3W output rating must be used. This is a stereo amplifier
board. The input section has two inputs L (Left) and R
(Right) and common ground in between them. It does not
require heatsink which also 25 saves additional board
space. Irrespective of the heatsink.
Fig-5: Pin description of Pam8403 amplifier
2.9 UV led
The germicidal effectiveness and use of UV rays is
influenced by organic matter, wavelength, type of
suspension, temperature, type of microorganism and UV
intensity. UV-C is germicidal ultraviolet light. It works by
deactivating the DNA inside bacteria, viruses, and other
pathogens thus effectively stopping their capability to
reproduce and spread disease. UV light in 200-280nm has
the ability to kill bacteria, viruses, mold, and fungi.
2.10 SMPS adaptor
The SMPS Power Adaptor - 12V/2A is a Switched mode
power supply SMPS. It is an advanced power supply. It
provides low losses and stable output. There is no need of a
rectifier. This high-quality Switching Power Adapter gives a
clean regulated 12VDC output at up to 2A. They work with
240VAC input.

3. BLOCK DIAGRAM
The shape of the box is rectangular and it is made of
plywood. The plywood is cut into several pieces and joined
together in the shape of a box. Two holes are made in the
front panel to insert our hands, and also a small
rectangular shaped cut is made to place the LCD display. A
speaker,dc switch and an smps adaptor plug is also fixed
at the right side of the box. The box is divided into two
chambers. The circuit part is placed in the lower chamber
and the upper chamber comprises two containers that
contain sanitizer. The fog maker floats on the sanitizer and
it functions at its time. The division of the chamber helps
to prevent falling the sanitizer droplets on the circuit and
avoid the short circuit. The back side is openable, this way
is used to stock the sanitizer into the container. A handle is
provided on the back panel to open.
Fig-7: Block diagram
3.1 Steps to operate
STEP 1: Insert your hands through the two holes provided
on the front panel.
STEP 2: check the input sensor for sensing
STEP 3: When the sensor senses the hands, the information
goes to the Arduino and checks for the activation of the Fog
Maker. At the same time, the UV light is also activated. The
LCD display placed over the front panel displays ``please
wait" to get our hand sanitized. The speaker functions with
the LCD display which speaks the sentences shown in the
display. If these are activated go to step 4 and step 5
otherwise repeat step 3.
STEP 4: The Disinfectant Solution is converted into the Fog.
STEP 5: We are ready to get our Hand Sanitized.
STEP 6: Check for the hand got sanitized by the machine.
The LCD display and speaker says "Thank you for using the
sanitizer dispenser". If the hand is sanitized, go to the next
step. Otherwise repeat step 2.
STEP 7: When the process is done, the machine will stop
and get ready for the next sensing.
4. CIRCUIT DIAGRAM
First the 230v ac coming from the line supply is given to
the SMPS adaptor which converts the voltage into 12v dc.
This 12v dc output coming from the SMPS is connected to
the dc in pins of the buck converter which converts the 12v
dc into 5v dc. This 5v is used to power all other
components in the system. This 5v is connected to the Vin
pin of the Arduino, and ground to ground pin. So the
Arduino is powered. The ultrasonic sensor is fully
connected with the Arduino such that the VCC pin is
connected to the 5V pin of the Arduino. TRIG pin to pin 5,
ECHO pin to pin 6 and ground to ground. The SDA pin of
the I2C LCD display is connected to A4 pin of the Arduino
and SCL pin to A5. The 5v is taken from the buck converter
and ground to ground.
CS pin of the SD card module is connected to pin 4 of
Arduino, CSK pin to pin 13, MOSI pin to pin 11, MISO pin to
pin 12, The 5v is taken from the buck converter and ground
to ground. amp in pin of the amplifier is connected to pin 9
of the Arduino. Speaker in pin is connected to the positive
of the speaker,and negative to negative pin, the 5v and
ground is connected to the buck converter.
Mist maker 1 is connected to the normally closed pin and
common contact pin of the relay module and the signal pin
of the relay module is connected to pin 7 of the Arduino.
Mist maker 2 is connected the same as mist maker 1 but
the difference is that the signal pin of the relay is connected
to pin 3 of the Arduino. 34 Another relay module is also
used for the UV LEDs. The normally closed pin is connected
to the 3.3v pin of Arduino, common contact pin to the
positive of the LED and negative to ground. The signal pin
is connected to pin 2 of Arduino
5. PROGRAMMING LANGUAGE
The program is written in the Arduino programming
language. Due to their simplicity, the programs written
using the Arduino IDE are called sketches. To save and
upload them to the Arduino board, we have to use the .ino
extension. Arduino programming language has three main
parts. First, functions that allow to control our board. Using
functions, it is possible to analyze characters, perform
mathematical operations, and perform various other tasks

– e.g., digitalRead() and digitalWrite() which help to read
or write a value to a certain pin. Another two are setUp()
and loop(). A sketch always starts with setUp(), which
executes once after the power-up or reset our board. After
creating it, use loop() to loop the program repeatedly until
power-off or reset the board. Next, the Arduino values that
represent constants and variables. Most of the data types
(array, bool, char, float, etc.) are similar to those of C++. It is
possible to perform type conversion as well. The structure,
the last part of the Arduino language contains small code
elements, such as operators.
Fig-8: Circuit diagram
6. RESULT AND CONCLUSION
The proposed work has many important advantages and
helps to kill viruses and bacteria in public places such as
train stations, airports and theatres. Its portable design
makes it easy to install and use in a variety of locations
depending on your needs. The technology used is still new
and very unstable. Using about 95% less sanitizer than
traditional sanitising, it solves one of the wastage
problems. The system is fully automated and avoids
manual mistakes and spreading of viruses from one
person to another. With this mechanism, people can
operate them comfortably, contactless, and very hygienic.
Fig-9: Open view and front view of the product
REFERENCES
[1] Pratibha RK, Kolhapure SA. Evaluation of the
antimicrobial ecacy and safety of pure Hands as a
hand sanitizer. Indian J Clin Pract 2005;15:19-27
[2] Weislander G, Norback D, Lindgren T.Experimental
exposure to propylene glycol mist in aviation
emergency training: acute ocular and respiratory
effects. Occupational and Environmental Medicine.
2001 Oct;58(10):649-55.
[3] Newman J, Hancock DD , Davis MA, Sheng H.
Comparison of a dry hand-hygiene research and soap
and water hand washing to lessen coli forms on hands
in animal exhibit settings. Epidemiol Infect.
2006;134:1024–1028.
[4] Health impact of handwashing. WELL fact sheet 2006.
at:
http://www.lboro.ac.uk/well/resources/factsheets/f
act-sheets htm/Handwashing.
BIOGRAPHIES
Hridhya AP, Lecturer in
Biomedical Engineering, EKNM
Government polytechnic College,
Thrikaripur, Kerala, holds B-tech
degree in Biomedical Engineering
from Calicut University and M-
Tech Degree in Ebedded system
from APJ Abdul kalam
Technological University.

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