Template for Project Development Entry
Our team Chemical Device
So, our team came up with the idea to make an automatic tea maker that can make the perfect cup of tea. Our tea-maker will be able to adjust accordingly to the type of tea used to like Chinese tea, green tea, earl grey, etc. This is to ensure that the tea is made at its optimum temperature and steeping time.
Chemical device sketch:
Team Planning, allocation, and execution
Team members:
CEO - Miguel
COO - Jun Weng
CFO - Brayden
Planned Timeline:
Actual Timeline:
Task Allocation:
Design and Build Process
In this section, provide documentation of the design and build process.
Part 1. Design and Build of Housing (done by Jun Weng).
https://cp5070-2021-2b02-group2-junweng.blogspot.com/
Part 2. Design and Build of gear & rack (done by Brayden).
https://cp5070-2021-2b02-group2-brayden.blogspot.com/
The video below shows how the Prototype of a smaller gear and rack came about. To test out whether the dimensions for the final gear and rack are usable, I decided to make a miniature version of the final gear and rack to test it. After knowing that it works, I left the 3D printer to make the hour-long final print.
The photo below shows the miniature gear & linear rack
The video below shows the first gear and rack design for the final design. I left this video in as I wanted to explain how the gear came about and how in the future, other people can find out how to easily make a similar gear to shape it to however they want. There is a script in Fusion360 that allows one to be able to make gear and this is something that I highly recommend as it not only cut down time but allows users for easy editing of new gear.
The photo below is the printed gear
For the video below, this is how I made the linear rack for the gear. So first of all, I made one of the teeth for the rack. I tried to imitate the teeth from the gear so after getting a generic shape where I felt happy about it. I duplicate the teeth along with the rectangle with the parameters I choose. After communicating with my group members, I found out that I need to make 2 protruding tabs with holes in them so they can each hold the temperature sensor and strainer. There is a picture that shows 2 racks and the top rack was rejected as there was a defect hence there is a reprint that is shown at the bottom.
The photo below is the rack in the process of being printed
The photo below is the failed rack and final rack
This is the rack that was designed and printed. After the print, I realised that I did not increase the BackThickness from 5mm to 30mm. This has caused the overall structure to not be as long as expected and it caused some problems where the strainer did not have sufficient space to be used. I have only realised this issue after assembling the final product and we did not have sufficient time to do another print hence we just went with this rack.
Part 3. Design and Build of supports (done by Jun Weng).
https://cp5070-2021-2b02-group2-junweng.blogspot.com/
Part 4. Programming of Motor, LCD & Temperature Sensor (done by Miguel).
https://cp5070-2021-2b02-group2-miguel.blogspot.com/
Part 5. Integration of all parts and electronics (done by all members)
Embed the finalized fusion 360 design files.
<iframe src="https://ichat2238.autodesk360.com/shares/public/SH35dfcQT936092f0e435df148f296524d6a?mode=embed" width="800" height="600" allowfullscreen="true" webkitallowfullscreen="true" mozallowfullscreen="true" frameborder="0"></iframe>
Documentation for integration.
Once all materials were ready, we put the housing together first. With the slots, it was easy to secure. We then added the cubes onto the corners, and then finally secured the slots with hot glue. The hinge for the door was put together with adhesive tape.
Next, we put the components inside. We set up the breadboard externally first, with connections to the components done later. We put the breadboard in the center of the base, and components at their respective holes laser cut previously.
The Arduino board was then placed on the side so that there is less tension between the wiring of the components and the breadboard. The Arduino board would be powered by a power bank.
Once the wiring was complete, we put the support onto the rack and attach the rack’s teeth to the gear’s teeth. After testing there was too much force on the rack that it cannot move. Hence solid scraps had to be used to keep their shape and allow for movement.
Finally, as the rack could not fit the weight of the sensor, we placed it on the side of the housing. Here is our finalised design:
Problems and solutions
3D Printing
Problem:
It was difficult to visualise and come up with the dimensions of the teeth for the linear rack.
The rack overall took a long time to print and make as there was a lot of experimentation with the parameters to make the final print.
Solution:
Make a small sample prototype to experiment and see if the design will work
Make the final design smaller and thinner
Programming
Problem:
The temperature sensor was not working on one Arduino board
Temperature sensor had started overheating despite the correct arrangement
No data came out
Solution:
After a bit of counseling and tryouts we found that the issue stems from the Arduino board and not the sensor itself
Had to only use one Arduino board for our prototype
Integration
Problem:
The supports had too tight a gap to be used for intended use
Original idea was to secure the rack using just 1 support
After testing, there was little to no linear movement with just 1 small support
Solution:
As one support is too small, we had to use different sized supports (scrap from our testing) to clamp the rack
Able to enforce a very smooth linear movement while reusing material
The linear rack is also not inserted in the support as planned
Limitations
Design Flaws
Stepper motor too weak
Original idea was to use 1 stepper motor and attach the temperature sensor and strainer onto the linear rack
Motor was unable to lift the linear rack more than once
Solution:
Removing the temperature sensor and strainer from the linear rack to put less stress on the stepper motor
Replace the current stepper motor with a 12V stepper motor for more power
Time Management - Many last-minute calls
Although we had followed the timeline we overlooked a few details
Set us back a lot & stressed us out till the end
Solution:
Do team meetings about logistics before any physical creation
Update each other about their workload & fill in gaps
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