Project Development
13 February 2022
Our Chemical Device
Our group decided to work on the Automatic Disinfection Chamber.
What is it?
It is used to Sterilize / Sanitize a human being autonomously, and our goal was to be able to disinfect a human being fully within the shortest amount of time possible.
Task Allocation, Execution of project and Planning
Our team made use of a Gantt Chart to organize our project schedule.
From Week 9 to 12 was more of the construction and technical side of the project where coding, laser cutting and 3D printing was done. The following weeks from Week 12 to 17 was where we got more hands on. Building our prototypes and fine tuning our designs, it was also the period where we took trial runs and tests to ensure that everything was working fine. The 2 weeks from week 17 to 18 was used to prepare our presentation slides.
Spray Mechanism
Allocation of Tasks
Alton (COO): Code + Fusion360 for 3D print
Leon (CSO): Sketching of chemical device and mechanism
Shou Chun (CFO): Fusion for structure
Sean (COO): Component Assembly
Ethan (CEO): Code
- Building of Chemical device was done by everyone-😁😁
Our Design Process
Our group first started off with the 3D printed design of our component housing and the CAD Design for our main chamber.
Component Housing: Used to house/store our Arduino Boards and wires.
Hero Shot of our component housing part
The above image and videos shows our Component housing being 3D printed in W3. We also started working on our CAD Design for our chamber using Fusion 360.
Hero Shot of our chamber structure
The images above shows our final CAD Design for our chamber, with one showing it being pieced together using the joint function in Fusion 360.
After completing the design of our main structure, we moved on to working on our mechanisms for our spray and rotating base.
This part of the project I believe took the longest among the other parts due to design failures and equipment malfunctions. This resulted to us changing the design multiple times and we shed a lot of blood, sweat and tears.😂
Servo mechanism
We made use of a servo to pull the spray handle back to spray out the "disinfectant".
Through a lot of Youtube videos and Googling, we were able to come up with a simple yet effective design to make our mechanism work!
Hero Shot of Spray
Rotating Base
The last part of our device was making the rotating base which will help rotate the user autonomously to be fully disinfected. We made use of laser cutting to cut out the base and a continuous servo mechanism to operate the base.
The above video shows how our rotating base will work when it is functioning.
This is Shou Chun fitting our rotating base platform into the component housing!
Hero Shot of Rotating Base
Design and Build Process
Alton (COO): Code + Fusion360 for 3D print
Shou Chun (CFO): Fusion for structure
Sean (COO): Component Assembly
Ethan (CEO): Code
My Individual Contribution (Sketching of chemical device and mechanisms)
For this project, I was in charge of sketching out our chemical device and thinking of the mechanisms we were going to use.
I started off with our initial idea sketch for our chemical device as shown below.
Our initial idea was really complex and involved many components as shown in the sketch which made it hard to establish. These components included: A pump, motor, sensor, nozzle, tank.
So we needed to come up with a new design which is more simplified but at the same time, maintaining its concept.
After a few weeks, we finalized our design and also started to work on our mechanisms for the rotating base and spray!
Our Finalized Design:
The two images above illustrates our simplified and final design. As you can see, the component housing acts as a base for our structure and the rotating base acts as a cover for the component housing! We got rid of the idea of using a pump and a separate nozzle and instead made use of a spray bottle mechanism which you will see later on!😁😁
Sketch of Mechanisms
For the mechanism of our rotating base, it was fairly simple to design and this was our design sketch of it.
The first image shows how the components will be placed in the component housing, this gave us a better understanding of our design and also made building the product a lot easier.
The second image shows how the rotating base was gonna look like. We used a continuous servo motor and a round servo blade, the blade of the servo motor will be glued to the bottom of the rotating base while the servo will be placed in the center of the component housing. The base will fit perfectly on top to cover our components.
Next up, we have the spray mechanism. This mechanism took the longest to build due to the design failures and equipment malfunctions like our servos not working properly. Our group actually had 2 different designs with one of the designs being unsuccessful.
Failed Design Spray V1
The above image was our initial spray mechanism design which did not work as the servo was too weak to press down the nozzle resulting in design failures.
We than decided to change our design by using a different bottle and design. It is also the design you will see in our final product.
Final Design Spray V2
Links to Team Members Blogs
Problems Faced
There were 2 main problems faced when we were building our chemical device. Firstly, our servo motors were too weak to pull the spray handle down, it would either get stuck or move only a little bit. This led to us swapping servos from a normal 0 to 180 servo we usually use to a MG90S servo which was much stronger and durable. However, since the servos were bought in bulk, there will tend to be faulty ones and that was the case for us. We were given 2 different MG90S servos and both of them were faulty!😡😡
So, we eventually had to stick with the normal servo we were using initially and had to change our design instead. This led up to the design sketch for the spray mechanism V2 as shown below.We also managed to get our hands on steel wires to aid in the mechanism.
Next, another main problem we faced was our Arduino. We had an Arduino board which had a loose USB connection. This led to the Arduino frequently disconnecting from our circuit and causing our mechanisms to stop working abruptly. To solve this issue, we had to find the perfect angle to hold the Arduino board and prevent it from disconnecting, so our group went ahead and made use of a plastic bracket to elevate the Arduino board slightly to prevent the USB connection from sliding out.
If you look closely at the image above, you will notice that our Arduino board is actually elevated by a plastic piece at the bottom. This actually helped solve our USB disconnecting issue and our device was able to run smoothly.
Our System Integration was not really done well as we did not take into account one of the important factors for our chemical device, which was ensuring that the wires and components were hidden and cannot be seen. This is to ensure that our chemical device look neat and nice on the outside and presentable to viewers. However, we were unable to hide our wires and components properly due to time constraints and because most of our pieces are transparent. In addition, our spray bottle was not "joint" with our main chamber, hence making it a "two-piece" chemical device. We would have made a bottle holder to hold the spray bottle to the chamber, making our chemical device one whole piece.
As you can see from this image. our wires and components are visible to viewers and not well hidden despite us covering it with the rotating base. Also, we tried our best to keep our wires neat by using duct tape.
And from the image above, our bottle and main chamber is separated from each other, which made our chemical device not a chemical device.. but chemical devices!!😂😂
Final Product and Project Files
Our Final Product
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