Most coffee machines look similar because they use a bubble pump design to push hot water into the brew basket. This design is simple and efficient, but it only offers limited control over the temperature of the brew water. Because of this, most machines brew with water that is too hot and burn the coffee.
I wanted to design a machine that looks different than any other machine and allows me to have better control over the brew temperature to keep it closer to the ideal range 195-205 F.
Warning: This project involves electricity, high heat, and water/steam. I will not be held liable damages and/or injuries resulting from the use of this code or from copying this project.
The machine is controlled with an Arduino Mega. You can find the source code for the project here:
I sketched a mockup in Google Sketchup. I wanted to give the machine a chemistry experiment look. I planned to move the water using a vibration pump from an espresso machine.
To heat the water I used a Saeco J Boiler from an espresso machine. I wanted the machine to match my espresso machine (Quickmill Andreja Premium) so I ordered similar styled lights.
I originally planned to only use the pump to prime the system and use the pressure of the heated water to push the water to the brew basket, similar to a bubble pump. I planned to regulate the brew temperature using a pressure relief valve vented to the reservoir. I ended up have trouble keeping the system pressurized without blow outs. So I switched to a non-pressurized system using the pump for priming and brewing.
I used a commerical Bunn decanter, brew basket, and spray head.
Built the case using aluminum angle and brushed stainless sheet metal.
I welded stainless steel rods make a mount the brew basket.
Wired and testing.
Video of it brewing: