Pour Over Coffee Bot: Intro

What gets me out of bed in the morning? The thought of coffee. What feels like the most mindless 5 minutes of my morning routine? Making pour over coffee.

For those not familiar with pour over coffee, it’s a method of brewing coffee that involves meticulously pouring water over fresh coffee grounds at set time intervals, resulting in a cup of coffee with amazingly rich and complex flavors. Maybe I’m a sucker, but I believe the flavor is significantly better than anything from a traditional “drip” coffee maker.

pour_over_coffee.jpg

As a Mechanical Engineer frustrated with the time required to make pour over coffee at home, I’ve decided to build my own pour over coffee machine! I’m excited by the opportunity to improve my mechanical design, electronics, and software programming skills – and document the process.

Design Considerations

If there’s anything that derails my projects, it’s attempting to bite off more than I can chew. Because of this, I’ll be keeping the project as simple as possible. While I’m sure it’s possible to build a system that handles everything from boiling water to brewing, I’m just going to focus on the brewing process. I don’t mind boiling water, pouring it into the machine, and then being able to walk away. Let’s take a look at the requirements for this device:

Functional Requirements:

  • Hold ~ 16 fl oz of water
  • Process water at ~ 90 – 100 degrees Celsius
  • Dispense water in a spiral pattern
  • Control water flow (start / stop)
  • Adapt to any coffee mug + dripper setup

Manufacturing Requirements:

  • Manufacturable with accessible “Maker” tools (3D Printer + Laser Cutter)
  • Purchased parts should be < $50 USD

With these in mind, the biggest challenge seems to be the mechanical design of how to “draw” spirals with the water. After weighing a few different options, I think the best solution involves a two-axis gimbal controlled by two servo motors. Doing some quick research, I found a variety of two-axis gimbal designs used for controlling drone cameras that I should be able to draw inspiration from.

servo-2-axis-gimbal.jpg

Similar to the above design, I plan to use a Hobby Micro Servo ($3.35) for one axis of rotation, mounted to a chassis that’s rotated by a larger, Standard Servo ($12.50). Together, these two servos should be able to aim the water to any position with some simple trigonometry.

To avoid cantilevered loads, I’ll be incorporating  8mm bearings ($0.50 each) opposite of each servo motor. This should also result in a sturdier assembly, which never hurts. Below is a rough drawing from Fusion 360 of the components making up the 2-axis gimbal.

2-Axis Gimbal Diagram

That’s all for now!

Next Steps: Complete design of Dispenser.

2 thoughts on “Pour Over Coffee Bot: Intro

Add yours

    1. The slower brewing process gives the water more time to come in contact with the grounds, and results in a more flavorful brew. Additionally, the process starts by pouring a small amount of water over the grounds and waiting 30-45 seconds to allow the grounds to “bloom” – releasing any C02 still trapped in the ground.

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