Like most engineering students, I love coffee. In first year, I heavily relied on my Tim Horton's Double Double every morning, but of course, that was a very wasteful and costly habit. In second year, I decided to invest in a Keurig to make coffee at home for myself, which was definitely more budget-friendly but still not the best for the environment. Due to this, I started reusing old K-cups and replacing the single-use filters with some reusable filters I found online. This was great as it was cheaper to buy coffee in bulk and I could also re-use all the old cups I bought previously. The only problem now was that it was quite time-consuming to empty each little cup and wash them. This is why I decided to create the Kleaner, a K-cup cleaning system shown below. Though the design could be cleaned up and improved, the general idea is that a K-cup can be inserted into the holder which is angled down and spins. There is a water pump with a nozzle that sprays up at the grounds in the K-cup and rinses out all of the used coffee into a sieve or filter to later be disposed of.
The Kleaner has three main components:
K-cup Holder — The main assembly consisted of a stand, stepper motor housing and cup holder. The parts were modelled in OnShape and then 3D printed. There was a pin-joint connection between the stand and motor housing to allow for angle adjustment and there was also a force fit between the stepper motor shaft and cup holder. The cup holder was modelled with a slight curve in the wall so that the K-cup could be held firmly with a friction fit.
Water Jet — The water jet was made with a very simple DC pump, reservoir, tubing and a custom printed nozzle. For now, the reservoir was just a small jar I found lying around, but in a later version, the reservoir could be modelled and integrated with the K-cup holder to conserve more space. A stronger water pump would also be helpful in a later version as the compact coffee grounds are difficult to get at with the current pump**.**
Controller — An Arduino Nano controlled all of the moving parts of the system. To start the cleaning cycle, a small button was wired and programmed to start the stepper motor rotation pattern and water pump. This was achieved by wiring and soldering the Arduino, motor driver, transistors, resistors and button to a PCB. Once everything was connected properly, a small script was loaded onto the Arduino which told it to start the motor and water pump after a button push.
Prototyping PCB — All of my experiences with soldering PCBs have been quite straightforward before this point as they were designed by people with experience and specifically labelled where components should be soldered. Due to the fact that I used a prototyping PCB, the connections I made were much messier than I hoped for and wiring was quite difficult even though so few components were used. I think that this was a good experience because it has encouraged me to learn more about real PCB design in future projects.
Part Integration — As it was difficult to say exactly how far the water jet should be from the K-cup and what the optimal angle was before testing everything out, it was difficult to create well-integrated parts and a compact system.
Importance of Prototyping — After creating this first prototype it was easy to see all the places this design could be improved, so it has really shown me how some quick prototypes can really help the design process.
Improved Soldering — After multiple attempts at trying to solder the PCB for this project, I feel that my overall soldering skills have improved due to extra hours of practice.