Here's another portable espresso machine and grinder

#1: Post by **foreclosurecat** » March 12th, 2023, 6:33 pm

Before I jump into the central topic, I just wanna thank the HB community for the past several years as I've been an avid lurker soaking up all the info.

Especially during the time we were locked down as it inspired me to do something coffee related instead of watching the news. I'm only a hobby level maker type, so that explains all the terrible design flaws and excuses up front.

What you're seeing here is a homemade 3D printed portable espresso machine. It has obvious inspiration from the Decent Espresso DE1. When I started the project I had no idea of a portafilter, screen, dose, grind, etc. Lockdown offered a great opportunity to learn all that so I bought a DE1 because others raved about it... that's about as much logic to it. Also, I am the breakfast and coffee provider at camping time every year with up to 20 friends/family at the site. I wanted to make a machine that could make espresso while camping and it had to be able to do back-to-back-to-back shots. It also had to have a workflow similar to home (i.e no Robot, Flair, etc) and capable of real 9-bar pressures. What you're seeing in the photos is that device.

It runs on an RC lithium battery pack. It is capable of following a pre-defined pressure profile. There is no flow sensor so it's not trying to be a portable DE1. It is software limited to 9-bar pressure which scares the he11 out of me because it's my programming skill, or lack of.

The grinder next to it is also (obviously) battery powered for camping. It has flat 58mm Mazzer burrs. Motor is capable of 300W spinning at 4:1 reduction. At most it only consumes ~40W with light roast grind at Turkish setting. The grinder display shows the heartbeat so things don't burn out. None of the watts or temperature get anywhere near concern.

If there's more curiosity about this nightmare device, we can discuss more below if this is the correct forum.

#2: Post by **coyote-1** » March 12th, 2023, 6:39 pm

Amazing. Incredible work!

#3: Post by **Pflunz** » March 13th, 2023, 9:58 am

I like both, espresso machine and grinder.

Do you have any more insights? What electronics you are using, what pump etc.
I guess water has to be externally heated?

#4: Post by **old442** » March 13th, 2023, 7:28 pm

Shut up and take my money!

#5: Post by **bgnome** » March 13th, 2023, 7:42 pm

foreclosurecat wrote:There is no flow sensor so it's not trying to be a portable DE1. It is software limited to 9-bar pressure which scares the he11 out of me because it's my programming skill, or lack of. The grinder next to it is also (obviously) battery powered for camping. It has flat 58mm Mazzer burrs. Motor is capable of 300W spinning at 4:1 reduction. At most it only consumes ~40W with light roast grind at Turkish setting. The grinder display shows the heartbeat so things don't burn out. None of the watts or temperature get anywhere near concern.

The original Decents did have flowmeters, but they were not used. John determined that they were not accurate enough at the low flow rates that occur during a shot. They use software to calculate flow based on the pulses of the pump and the live pressure reading.

The grinder also looks interesting as it is clearly Kafatek inspired.

Are you planning on releasing your CAD files?

#6: Post by **TenLayers** » March 13th, 2023, 8:11 pm

Lovin' it! And the camping aspect is cool as hell....errr hot as.

March 13th, 2023, 10:36 pm

More insights... electronics in the espresso is an ESP32-S2 (overkill but it was given to me so had to use it), pump is a Modbar/LaMarzocco gear pump. Using an RC brushed motor controller which means the ESP32 pushes out a PWM signal from the Arduino RC library based on the pressure profile and PID software... pretty conceptually simple but was temperamental at the early stages.

And yer right - water has to be externally heated. But that plays into an acceptable workflow at camping where we can heat up a pot of water and keep pouring the boiling water into a Mason jar with the silicone intake tube. Keep in mind altitude is about 8,000 feet so any real calculations of heat, pressure, and all that has gone out the window. I don't want to think about all that stuff because it is a deep rabbit hole. Pragmatically as a side note, of the 20 campers, 90% all want milk and sugar which leaves only two hardcore coffee freaks that really care about bean origin and light roast level. So any dark roast with a decent pull will work fine - especially at camp where there's ZERO coffee shops.

March 13th, 2023, 10:47 pm

bgnome wrote:Are you planning on releasing your CAD files?

Wasn't planning on it, but would gladly share if it was easy to do. It's all in Fusion 360 and keep in mind this is hacker-level skill, not real talent. If I can figure out how to share it all really easily I'll make it happen.

March 14th, 2023, 1:32 am

Pflunz wrote:... and grinder.
Do you have any more insights? What electronics you are using...

Grinder was a bigger nightmare. Electronics inside you'll find a VESC controller and ESP82666 with GC9A01 display. There's an old video I posted here with a 3D printed hand grinder to see how much force was needed to grind with the Mazzer 182D burrs. Turns out not much torque was needed so I chose a brushless robotics NEO motor with 4:1 planetary reduction. Overkill for the task but easy to work with. Brushless motor is RPM PID'd via hall sensors and FOC. RPM is 0 to 1,400 with realistic RPM starting around 300. I sized the enclosure to be as small as possible which was a mistake that no one can see. The electronics are extremely tight inside that little 3D printed plastic case with wood veneer wrap. There is no breathing room which made assembly a nightmare... but enough complaining.

The top wood veneer grind scale is laser burned 0 to 10. Thread pitch on grind adjustment is 1.5mm per revolution which means 1/3 of a turn is .5mm or 500um. Therefore, each digit is 50um which is helpful when dialing in espresso. The kafatek has obvious influence.

Grind retention is a bear. Light roasts are ok, but dark roasts tend to remain hidden inside the chamber mostly on the burrs. Guess-timate retention is over a gram. Retention at camping isn't a big deal since the grinder is merely pumping out volumes into a cup and dosing is done at the portafilter on a scale.

Battery holds 44,000 milliwatt-hours. Each 15gm dose takes about 600milliwatt-hrs. (fun for those who like math). The display shows the energy consumption on each grind (sorry, I didn't realize the photos are too tiny).

I don't have many photos of the grinder build, but the body is made from marine HDPE and the sweeper is aluminum. Hidden under the burr is a 58mm bearing. Logic behind that choice was to allow the burr loads and pressures to sit directly on the bearing and not worry about shaft wobble. I knew this going in because my hobby CNC machining is not accurate enough. However, burr alignment is very decent and grinding with the 58mm Mazzer burrs makes for "great" espresso. SSP brew burrs are begging to be purchased to make a 2nd grinder just for pour over. Possibly not a wise move.

March 14th, 2023, 11:16 am

Why must you tease me like this!? I wish I had talents like yours. Very cool!