2B05 Group 1 Anthony's Blog: Project Development

1. Our team 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, where many different people touches it. The device’s 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.

2. Team Planning, allocation, and execution

Team members and their roles

Wei Xue (Team leader)

Firmanshah (Chief Financial Officer)

Anthony (Chief Operating Officer)

Lionel (Chief Security Officer)

Rufus (Chief Financial Officer)

Bill of Materials

Project Title:	Automated Door handle sanitiser
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 (Include hyperlink to the item in website of seller)	quantity	quantity unit		unit price		Total Cost	Available at W319 Lab or FabLab? (Y/N)
1	Infrared sensor Module	https://sg.cytron.io/p-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)	https://shopee.sg/Clear-Acrylic-Sheet-A3-Size-(297mm-x-420mm)-Thickness-2-3-4-5-6-8-10-12mm-i.438933164.2953999830?sp_atk=68a086bd-da2a-40e6-aaf2-7abbfbfe395b	1	374.22 cm3	$7.90	$7.90	Y
5	Spray Bottle	https://shopee.sg/Small-Spray-Split-Bottle-Hydration-Fine-Mist-Spray-Bottle-Empty-Bottle-Set-Bottle-i.195689654.5393375158?sp_atk=4d3313f9-f5af-4391-8598-581046304c37	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

Gantt chart and Task Allocation

People in charge of the following tasks:

Design Ideation: Everyone in the team

Programming and Setup of Arduino Circuit: Wei Xue and Lionel

Design of Box: Anthony

Design of Components in box: Everyone in the team

Purchasing of materials: Everyone in the team

3D Printing and Laser Cutting of Box and Components: Firman and Rufus

Assembly and Building of prototype: Everyone in the team

3. Design and Build Process

In this section, provide documentation of the design and build process.

Part 1. Design and Build of Bottle holder 1 (done by Firmanshah).

https://cp5070-2021-2b05-group1-firmanshah.blogspot.com/p/project-development-entry.html

Part 2. Design and Build of Bottle holder 2 (done by Rufus)

https://cp5070-2021-2b05-group1-rufus.blogspot.com/p/project-development-entry.html

Part 3. Design and Build of Arduino board holder and box (done by Me, Anthony).

So I will be showing how the Arduino holder was designed first. We measured the Arduino board, and it was 60mm x 69mm which is around 60mm x 70mm. We then drew out a ‘map’ of the board and split it into 10mm x 10mm squares to identify areas where there are no protrusions so that we can place supports.

After analysis we are then able to sketch out a design for the holder.

We then transferred it to Fusion 360 to be printed.

Here it is printed!

Now onto the box. We want to laser cut a press fit box so we needed dimensions for the box so that I can be a tight fit but still hold all the components. Firstly we measured the components so that we can get the general size of the box.

Then using the initial sketch we had and transferred it over to fusion 360 using the exact dimensions.

Then we boxed it in to achieve a tight fit.

We measured this box and using these values, we decided on the dimentions of 17.5cm x 15cm x 7.5cm. Since it was press fit we placed these values into this website, https://en.makercase.com/#/basicbox. We then got this DXF file.

Putting it into the laser cutter and we got our pieces.

Part 4. Coding of Arduino and circuit setup (done by Wei Xue).

https://cp5070-2021-2b05-group1-weixue.blogspot.com/2022/02/project-development.html

Part 5. Coding of Arduino and Circut setup (done by Lionel)

https://cp5070-2021-2b05-group1-lionelneo.blogspot.com/p/project-development.html

Integration/Assembling the prototype

During our assembly of prototype, it was a group effort conducted by all. On 11^th February, we met up in school to build our device.

So this is our planning stage where we determined where each part would be in the device.

Next, we assembled the acrylic casing using acrylic glue.

After gluing the acrylic case together, we started to assemble the interior pieces of the device using super glue and double-sided tape.

Next, we attached the acrylic hinge onto the casing so that we can open and close our device.

Afterwards, we attached our wires, Servo motor and infrared sensor into the case.

Lastly after the glue is dried, we place our spray bottle in and tested our device.

https://youtu.be/MsN0C-tHW1U

4. 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.