In Docker Containers and Coffee, I promised would talk about layering a digital control system on a purely analog device. But let me first give a little background about myself. My name is Alex Moyse, and I just finished my Electrical Engineering degree at BU, and while I undergo my job search, I want to take on other technical projects and challenges. One of those is to make an IOT espresso machine from a La Pavoni, an espresso machine originally made in 1905. So let me first provide a bit of background on the La Pavoni I am using:
Picture from Houzz.com: bit.ly/2vhV7rH
As you can see the system is very simple, there is not a high pressure pump, nor a modern control system. All there is a pressure stat: a device that is on when the pressure is below a certain value, and off when it is above it. It’s entirely mechanical, with no computer control. You can seem simple this mechanism is by this photo:
Picture from https://bit.ly/2M76MRD
VS a modern espresso machine with a pump and digital control.
From https://bit.ly/2vrHaI3
As you can see, there is so much more less circuitry in the La Pavoni. The main reason is that there is no pump to push the water through the coffee. Instead, you, the user, must pull on the lever in the front to generate enough force to brew Espresso (which by my calculation is ~15 lbs). This means that the muscles in your arm, determine everything about the shot of espresso you make, from the amount of crema, to the flavor of the shot. This means that you the user are a key component in this machine. I wanted to automate a La Pavoni as I’ve been able to make fantastic shots of espresso with it, but on the other hand, I’ve also made some terrible shots with it. A great example of puling espresso on a la pavoni can be found here:
Practically, starting with a La Pavoni enabled me to modify everything I wanted to, from the ground up, without forcing myself to recreate custom code and PCBs. The La Pavoni’s hardware naturally regulates its temperature, and while it does have some downsides, the simplicity of this system is unmatched. This is the end of the first portion of why I started with a La Pavoni as the basis for my IOT espresso machine. Soon, I will go into more details regarding the electronics and theory of digital control.