Project Development
Our team's Chemical Device
Our chemical device is a door handle sanitizer. It aims to reduce the problem of high infection rates of Covid-19 through indirect contact by an infected person. This can be through everyday objects that have been contaminated such as the door handle. Its function is to detect the hand on the door handle and spray hand sanitizer onto the door handle after a person lets go of the door handle. By doing so, it kills any bacteria or viruses on the door handle which in turns reduces the risk and reduces the rate of Covid-19 infections through indirect contact.
Team Planning, allocation, and execution
Firmanshah (Chief Financial Officer)
Anthony (Chief Operating Officer)
Lionel (Chief Security Officer)
Project Title: | Automated Door sanitiser | ||||||
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Team members: | Anthony, Wei Xue, Firmanshah, Rufus, Lionel | ||||||
Created by: | Anthony, Wei Xue, Firmanshah, Rufus, Lionel | ||||||
Date created: | 16/12/2021 | ||||||
BILL OF MATERIALS (BOM) | |||||||
No | Description of item | Supplier | quantity | quantity unit | unit price | Total Cost | Available at W319 Lab or
FabLab? (Y/N) |
1 | Infrared sensor Module | 1 | - | $0.68 | $0.68 | N | |
2 | Maker UNO Edu Kit | https://robot-r-us.com.sg/p/maker-uno-edu-kit-arduino-compatible | 1 | - | $18.70 | $18.70 | Y |
4 | Clear Acrylic Sheet | A3 Size (297mm x 420mm x 3mm) | 1 | 374.22 cm3 | $7.90 | $7.90 | Y | |
5 | Spray Bottle | 1 | 150ml | $0.64 | $0.64 | N | |
6 | Acrylic Glue | https://artfriendonline.com/OnlineUsers/Product/PAP_PAD/PAINTING/ACRYLIC | 1 | 50ml | $3.85 | $3.85 | N |
7 | Acrylic Hinges | https://artfriendonline.com/OnlineUsers/Product/PAP_PAD/PAINTING/ACRYLIC | 1 | - | $3.90 | $3.90 | N |
Grand Total Cost: | $35.67 |
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Finalized Gantt Chart
Roles
Programming
and Setup of Arduino Circuit: Wei Xue and Lionel
Design
of Box: Anthony
Design
of Components in box: Everyone
3D Printing and Laser Cutting of Box and Components: Firman, Rufus
Design and Build Process
Part 1. Design and Build of Part A (done by Firmanshah): Firman's blog
This is the code that he used:
#include <Servo.h>
Servo myservo;
int pos;
int Signal = 8;
int LastState = LOW;
int SensorState;
void setup()
{
pinMode(Signal, INPUT);
//Sensor set as digital input
myservo.attach(9);
//Server set as output
}
void loop()
{
SensorState = digitalRead(Signal);
delay(1);
if
(SensorState != LastState) //if it changed and it's high
{
if
(SensorState == HIGH)
{
Spray();
//Sanitize the door handle
}
}
LastState = SensorState;
//save current sensor input value for next
comparison
}
void Spray() //spray operation function
{
delay(200);
for
(;pos >= 40; pos -= 1)
{
myservo.write(pos);
delay(15);
}
for (;pos <= 80; pos += 1)
{
myservo.write(pos);
delay(5);
}
}
//end program
So, based on his code, the Arduino board
will check the state of the IR sensor. If it’s in the high state (a hand is
detected), a signal is sent to the Servo Motor to run the Spray function, which
is defined at the bottom lines of the code. The Spray function includes the
delay for the hand to move away before the Servo Motor is in motion. The spray
function basically makes the servo motor swing the servo arm to press down on
the spray bottle and return to its original position.
We wanted the servo arm to have larger a range
of motion, therefore, we changed the start and stop angles of our servo arm,
and also the time taken for the servo arm to perform each action.
#include <Servo.h>
Servo myservo;
int pos;
int Signal = 8;
int LastState = LOW;
int SensorState;
void setup()
{
pinMode(Signal, INPUT);
//Sensor set as digital input
myservo.attach(9); //Server
set as output
}
void loop()
{
SensorState = digitalRead(Signal);
delay(1);
if
(SensorState != LastState) //if it changed and it's high
{
if
(SensorState == HIGH)
{
Spray();
//Sanitize the door handle
}
}
LastState = SensorState;
//save current sensor input value for next comparison
}
void Spray() //spray operation function
{
delay(1000);
for
(;pos >= 30; pos -= -10)
{
myservo.write(pos);
delay(10);
}
for
(;pos <= 120; pos += 1)
{
myservo.write(pos);
delay(5);
}
}
//end program
Arduino Setup:
For our Arduino Setup,
IR Sensor: pin 8
Servo motor: pin 13
Voltage wires would all be attached to a breadboard.
Arduino board will be secured in place by
the 3D printed Arduino holders.
Proposed Setup
Next, we attached the acrylic hinge onto the casing so that we can open and close our device.
Final Product
Problems and Solutions
Problem
1: When we were using our first bottle holder
design, we realized that if we were to put
the bottle into the holder and secure it into the container, we realized that
we were not able to remove the
bottle from the side.
Solution: Our solution was to cut the bottle holder that Firman made into a
semi-circle to allow users to replace the spray bottle as and when it was empty.
This would allow us to replace the bottle from the top instead of the sides.
Problem
2: Servo motor was not strong enough to push down
the spray bottle.
Solution: We decided to cut the spring inside the spray bottle to lower the
spray bottle resistance. Another solution we did was to increase the range of
the servo motor from 40-80 degrees to 30-120 degrees to give it more power to
press down the spray bottle.
Project Design Files as downloadable files
1
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