This is a great project. I would like to point out that it is possible to have an extremely good espresso machine with zero electronics if you don't mind some occasional exercise. It's called the Espresso Forge and it puts out excellent espresso. It will also never break because there just isn't much to it besides an o-ring that may need to be replaced every few thousand espressos. The rest of it is stainless steel.
There are many manual espresso machines out there, one of the most iconic in recent years being the Cafelat Robot http://www.cafelat.com/robot.html. There are lever/piston machines going back to the 1940s.
Indeed, the Robot is a wonderful piece of good old engineering, and it makes fantastic espresso without much fuss. Haven't had to do any maintenance since I got it, almost four years ago.
And best of all, shameless plug ahead: It's easy to hack, for example if you want to add much needed electronics, like I did with this scale here: https://youtu.be/awvB3pJCmEo (Oh the irony, but some things just need to be done.)
I have not tried the EVO. If you want to save a few dollars due to the lower cost of aluminum metal the EVO looks functionally identical to the fully stainless steel original. Aluminum is a neurotoxin so I have no problem paying more for stainless steel metal.
