Breaking New Grounds (An Engineering Exploration in Building a Coffee Machine, part III)
As I look at the many components of the prototype, I wonder when “the whole became greater than the sum of the parts.” The inflection point might have been after I made the first cup of coffee, or perhaps it was when the software brought the machine to life with a low hum, or when the European caffeinated air gave me the idea. Despite the question, the “Gauss Press Mark II” is real, sitting on my counter, waiting to make me a strong bold coffee with an Alexa® command.
As I developed the Gauss Press, I was constantly reminded that this machine does not exist to Google. Search results for things like “replacement valve for Gauss Press Mark II” simply aren’t available. Despite years of software development and innovation, somehow this is always new, different and surprising.
Note: The Mark II addition is an homage to Stan Lee’s Iron Man versioning scheme.
From concept and vision, through software development, refinement, caffeinated nights and weekends, I now had a fully working machine and platform to build on top of. The irony of coffee powering the engineering and the engineering powering the coffee was not lost on me.
A quick recap from Part I of this exploration includes building a machine to produce a great cup of coffee with deceptively simple goals such as:
- It needs to make coffee consistently, and repeatably.
- It needs to have an aesthetic that I would appreciate on my counter (I’m a big fan of Apple® design and engineering).
- It needs to be software, and hardware controllable for precision
- It needs to be operated via web/mobile and Alexa®
- It needs to be food grade, and easy to clean
- It needs to support multiple filters, and work for different grains/grounds
- It needs to be easily serviceable
“The sculpture is already complete within the marble block, before I start my work. It is already there, I just have to chisel away the superfluous material.”
― Michelangelo
On Design
At the core of the design is an open view of the brew process. The design is comprised of many custom hand-machined parts, several precisely machined CNC parts, as well as off the shelf parts to achieve the final design goals. The prototype is made largely of high quality stainless steel, borosilicate glass, and sealed black walnut with food grade contact parts.
Mechanical components and electronics are neatly hidden away under the steel shell. The design features an open view to see the brew process in motion. With zero physical buttons and minimal extrusions with cylindrical components the design is unique and symmetrical.
The design also includes consideration for different filter types and service-ability. Meticulous detail was put into the placement of every component and screw. Finding ways to neatly package the electronics out-of-view was a design challenge requiring the development of custom fabricated components.
On Function
At the heart of the Gauss Press Mark II is software and hardware operating as an IoT device. Since the machine has no physical buttons it is software driven via external API’s, UI and voice. The software running on the machine hardware is responsible for precision control over the components and timings, with high-level API’s for web/mobile/Alexa®.
In addition, the prototype supports many permutations to the brew process driven through the API’s. Calibration, cleaning and testing components was core to the function and development. Finding the right power supplies, motors, sensors, bearings, stepper drivers, and control boards with specifications that suited the application was key to developing the functionality. Smooth, quiet functionality was achieved through proper motor control.
The micro-controller logic and API’s, React UI, Alexa skill and cloud broker service all required a fair amount of planning, thought and development.
Did I achieve my goal to produce a great cup of coffee?
Yes (with bias). Through software tweaks, hardware upgrades, invention, modified brew methods, filters and process updates, the coffee tastes bold, and smooth. Importantly, the taste is repeatable and the prototype is configureable at the API level and on the UI. The permutations to do things such as: run with an open valve, modify the brew timings, run multiple passes, start the brew process early, late, agitate throughout the process, change the filter, can produce interestingly different and repeatable results. I personally like running the machine slowly, agitating the grounds with the valve closed, while using a fine filter. And I like to use the Alexa to drive it.
What is the brew method and process?
It’s a hybrid process, similar to a french press/pull. It’s automated for precision and repeatability with some elements from a vacuum and pour over. It uses precision stepper motors/drivers with a micro-controller for a slow and steady control. The UI, Alexa voice commands, and API’s allow me to control the process with repeatable precision and ease of use.
What are the things I would improve upon?
One of the most enjoyable parts of the process was also envisioning what a Mark III would look like and learning the skills required to build on top of the Mark II technology. I’ve kept a running list of possible upgrades and improvements along the way that span function, design and mechanics.
Could it make tea as well?
Yes
Does it do espresso?
No
Can I buy one?
No, it’s purely a prototype. This was an engineering and design exploration and personal challenge.
If you have not yet had a chance to check out Part I or Part II please check out those posts as well.
I hope you have enjoyed this three part series in the design and exploration of building a custom coffee machine. I learned an incredible amount designing, and developing this machine while inventing a new coffee brewing device.
If you’re interested in my work, or development, please contact me.
Feel free to reach out via email @ smithxlabs [at] gmail, and follow me on twitter @ smithxlabs
© 2020 Bryan Smith All Rights Reserved.
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