Final: Product Development
Our team Chemical Device
So, our team came up with the idea to make an automatic tea maker that is able to make the perfect cup of tea. Our tea-maker will be able to adjust accordingly to the type of tea used like chinese tea, green tea, earl grey etc. This is to ensure that the tea is made at it’s optimum temperature and steeping time.
Chemical device sketch:
Team lanning, allocation, and execution
Team members:
CEO - Miguel
COO - Jun Weng
CFO - Brayden
Planned Timeline:
Actual Timeline:
Task Allocation:
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/
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 me, Miguel).
Firstly, I had done research and tested code for each component first.
For the temperature sensor and motor, these were relatively simple as their codes could be found in their respective Cytron listings. I had taken from these sources for the temperature sensor and motor, respectively:
https://www.youtube.com/watch?v=avrdDZD7qEQ&feature=emb_title&ab_channel=NikodemBartnik
I then improvised it to create a more closer-to-actual-use prototype. The motor would be tested of its movement with the cog, while the sensor would show a reading in the system
I also looked through the components' recommended set up, and re-created it to the breadboard.
Once those were settled, I tested both. And well, they both worked! The sensor had shown an accurate value, while the motor was able to move the cog well. I then pushed it one side for a while.
Lastly, I had to take care of the LCD. There had been no way to find premade LCD code and hence a whole lot of it was made in scratch. I followed the directory shown here:
Using the directory, I visualised and made use of the code shown below:
The LCD would show "Testing..." on the first row of the LCD, then "1 2 3" sequentially on the second row of the LCD.
Finally, all 3 codes were working! Now to put it all together. I first adapted the LCD and sensor to work together, with the reading showing up on the LCD. Here is a showcase of that integration:
Now that everything's integrated, it's time to streamline all the wiring. This is how the set-up would look like as it is:
I then tested it with a prototype code, before creating my working code. Here's how it would look with the above set-up!
All code can be found under this link:
https://drive.google.com/drive/folders/1GSBfYs5NtsTbKUCJGHG9oQ7YE_nyhrw-?usp=sharing
Part 5. Integration of all parts and electronics (done by all members)
This is how we ideally wanted it to look on assembly:
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 centre 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:
This leads us to our final showcase: how the device would work. See the video below!
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 correct arrangement
No data came out
Solution:
After a bit of counselling 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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