Project Development Entry

 

1. 1. Our team Chemical Device 

2. 
   

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 touch 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 turn reduces the risk and reduces the rate of Covid-19 infections through indirect contact.

2. Team Planning, allocation, and execution 

Team name: Dreamers

Team members:  

Wei Xue (Team leader) 

Firmanshah (Chief Financial Officer) 

Anthony (Chief Operating Officer) 

Lionel (Chief Security Officer) 

Rufus (Chief Financial Officer)

Before we are able to move forward with our project, we would need to make the Bill Of Materials first.

Next, our team made a Gantt chart as a schedule planner so that we would keep to our schedule and not waste any time. Here is the roughly planned Gantt Chart that we made:

 Here is our actual Gantt Chart that was used:

People in charge of the following tasks from Actual Gantt Chart: 

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

Firstly, we made some sketches of what our prototype should look like. Here are some sketches that our team made:

For our prototype, we first wanted to focus on the components that will be holding the spray bottle in place in a box. The design files can found at the bottom of the blog page.

Part 1. Design and build of bottle holder design 1 (done by Me, Firmanshah)

I was tasked with the bottle holder design. It should be able to hold our bottle in the box of the door handle sanitizer so that it ensures that our spray bottle stays in place and does not move around when the servo presses the atomizer downwards. We found that the diameter of the spray bottle was 2.3cm and I decided to make the bottle holder design based on that diameter. On fusion360, I made the bottle holder as shown with a diameter of 2.5cm. 

After designing it, I then went into the Cura app to 3D print the bottle holder. Here is how it looks in Cura: 

Hero shot for task 1. 

Part 2. Design and building of (link: spray holder v2) (done by Rufus, link to Rufus's work)

In this section, my groupmate Rufus, made another bottle holder design just in case the first design did not work. To know more about what and how this bottle design works, you make take a look at his blog through this link: https://cp5070-2021-2b05-group1-rufus.blogspot.com/p/project-development-entry.html

 Here is a hero shot of his work:

Part 3. Design and Build of the Arduino holder and box (done by Anthony, link to Anthony's blog)

In this section, my groupmate Anthony designed the Arduino holder and also made the box for the internal components. To know more about the process of his work. you may take a look at his blog page through this link: https://cp5070-2021-2b05-group1-anthony.blogspot.com/p/project-development.html

Here are some hero shots of his work:

Part 4. Design and Build of the Arduino coding and setup (done by Wei Xue and Lionel, link to Wei Xue and Lionel's work)

In this section, Wei Xue and Lionel made the coding to the Arduino and the wiring setup for it to work. They will be explaining more about how the code works on their blog page. Here are their blog links to their work:

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

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

Here are some pictures of their work:

Part 5. Assembling the prototype (done by Everyone)

During our assembly of the prototype, it was a group effort conducted by all. On 11th 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. 

Afterward, 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. 

And here is the final door handle sanitiser:

Here is an embedded design file of the prototype: 

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.

5. Project design files as downloadable files

For the files, we compiled them into a single google drive link where you access them through this link: https://drive.google.com/drive/folders/1IoNjm2DpI6_LEMhrlyfs-UZPBVXQFM2x?usp=sharing