Embedded Files
The Automated French Press
Final Product CAD Model
Aluminum Frame
A basic aluminum extrusion frame was assembled because of it's great versatility to change shape and mount components and assemblies. Cross sections of the aluminum extrusion are 20mm x 20mm squares.
Control Board
Acrylic was laser cut to organize and mount all of the power and logic electronics in the Automated French Press. The power/logic schematic details how all electrical connections and components were grouped and routed.
Plumbing
Water and Coffee were transported with water-tight and food-safe plumbing components, i.e. valves, pumps, tubing, and fittings. Teflon tape and C-Clamps were also integrated to make connections water-tight. The Flow Diagram on the right details how liquids are transferred.
Water Heating Module
The water heating module is essentially a COTS kettle with a bulk head fitting attached to pump out hot water and a temperature sensor to sense when to start pumping. The kettle, pump, and valve are all mounted on a slanted ramp (not shown) to provide enough head to prime the pump.
Grinding ModuleThe grinding module is made up of multiple components: a reverse-engineered COTS burr grinder, a custom laser cut mount, a Solid State Relay for Arduino control, and a push-in, 3D printed ramp to route grinds into the Brewing Canister. To ensure the proper coffee-to-water ratio, a linear relationship between grind time and output mass was found. The figure to the right depicts the input time required for 1, 2, and 4 cups (250, 500, and 1000mL respectively).
Hot coffee is served on the right side. A variable-height faucet was fabricated to allow a user to use different size containers, which would be necessary if the user is brewing 1 cup or 4 cups at a time.
Brewing and Serving Module
Coffee is brewed on the left side of the front of the Automated French Press. The Brewing Module consist of a Polycarbonate bottle, which is food-safe at water-boiling temperatures. A custom filter was designed, first out of acrylic and 3D printed parts and a final version from aluminum and sheet metal to ensure structural integrity and food safety.
To make it user friendly, the Automated French Press incorporates an LCD screen that allows users to select: 1 cup, 2 cups, 4 cups or cleaning with the press of a button. At the beginning of a coffee cycle, a small amount of water is flushed through the system to clean the lines of residual coffee from previous use. A separate bottle inside the machine contains the fluids emptied out by the cleaning cycle.
The French Press performs well. The main timing constraint is the amount of water in the reservoir when heating, but even when the reservoir is full, the French Press can produce coffee in under 15 minutes. The process is outlined in the Timing Diagram.
User Interface
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