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YOU CAN REBUILD A CHEAP ESPRESSO MACHINE WITH THE CONTROL FEATURES OF HIGH-END ONES

Rebuild the Gaggia Classic into a machine with temperature control, pressure and flow profiling, live shot graphs and programmable profiles — features usually found on high-end machines.

by Zer0-bit and contributors

FULL CAD BOM FIRMWARE DOCS

HomeOpen-hardware

Built withSTM323D printing

difficulty
●●●●●
time
several weekends
license
CC-BY-NC-4.0
repo
repo ACTIVE2,674 stars

WHAT YOU’LL NEED

1
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COMPAREE VERDICT

Gaggiuino turns the Gaggia Classic, an entry-level single-boiler machine, into one with high-end control features. After the mod you get temperature control, pressure and flow profiling, programmable profiles, live graphs on a touchscreen or in a web interface, shot history and stop-on-weight with supported scales. It is a genuine engineering project, not a plug-in accessory. You open a mains appliance, install a control PCB (sold by approved suppliers, or built from components), mount a pressure transducer into the brew path, rewire the pump and boiler control, and flash firmware. The barrier most people hit is not the soldering — it is the confidence to work inside a pressurised, mains-powered device. Check your model first: the Gaggia Classic V2 from 2015-2018 is not supported. If you have never opened an espresso machine before, this is not the place to start. If you have, or you are willing to move carefully and ask questions, the documentation is thorough and the Discord help channels are active. The project is licensed CC BY-NC 4.0, so personal builds and modifications are fine but commercial use is not. The result is a machine you understand completely and can program shot by shot.

GOOD TO KNOW

  • —Step-by-step install guides, wiring diagrams and the bill of materials are on the official documentation site (gaggiuino.github.io); firmware is distributed as release binaries on GitHub.
  • —Licensed CC BY-NC 4.0: free to build, share and adapt for personal use, but commercial use is not permitted.
  • —This is a full rebuild of a mains-powered appliance. You solder, mount sensors into pressurised hydraulics, and rewire the machine's controls.
  • —The docs open with a warning that safe electrical practice is critical, and the licence disclaims all warranties and liability: you build and use it at your own risk.
  • —Active community on Discord, with dedicated install-help channels for the Gaggia Classic and Classic Pro.
  • —PCBs, kits and printed parts are available from the approved official suppliers listed in the documentation; the donor machine is sourced separately.

Parts to buy

8 items

From our check of the build. Exact quantities and part numbers are in the creator’s BOM.

  • Gaggia Classic donor machineFind
  • Gaggiuino PCB or kit from an approved supplierFind
  • STM32 microcontroller plus ST-Link programmerFind
  • K-type thermocoupleFind
  • SSR-40DA relayFind
  • 0–1.2 MPa pressure transducer and fittingsFind
  • Touchscreen or headless setupFind
  • Optional scalesFind

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Can I build this?

PrintCustom panels and board mounts — buy them from an approved supplier or print them from the design files linked in the documentation. The build works without them but the finish is better with.
BuyGaggia Classic donor machine (used is fine if the boiler and pump are sound), Gaggiuino PCB or kit from an approved supplier, STM32 microcontroller (STM32U585 for Gen 3 or BlackPill F411 for Gen 2) plus ST-Link programmer, K-type thermocouple, SSR-40DA relay, 0–1.2 MPa pressure transducer and fittings, touchscreen or headless setup, and optional scales. The official documentation has the full bill of materials with part links.
ToolsSoldering iron, multimeter, crimping tool for spade and fork terminals, screwdrivers and spanners for hydraulic fittings, and an ST-Link programmer with the flashing software from the docs.
SkillsIntermediate soldering, confidence working with mains voltage, and enough mechanical sense to mount a transducer into a pressurised brew path without creating a leak. If you have built a 3D printer from a kit or rewired a car stereo, the skills transfer. If you have never soldered or worked inside anything plugged into the wall, start somewhere with lower stakes.
TimeTwo to four weekends if you have soldered before and the PCB arrives assembled. Budget another weekend if you are learning to solder SMD components or troubleshooting a first build that does not boot.
CostHigh budget — dominated by the donor machine, the PCB or kit and the Gen 3 screen from an approved supplier, plus optional scales. The documentation does not publish prices.
SafetyMains voltage throughout. You are rewiring the boiler and pump circuits, both of which run at 230V (or 120V in North America). The pressure transducer mounts into the brew path, which runs at 9+ bar when the pump is on. A poor solder joint, a loose hydraulic fitting, or a failure to isolate the mains properly can cause electric shock, scalding, or a high-pressure water leak. The project explicitly states you do this at your own risk. If you are not confident working inside a mains appliance, do not start here.

This build involves mains voltage — for adults comfortable with electrical work only.

Build at your own risk. Projects involve tools, electronics and sometimes mains voltage — follow the creator’s safety notes.

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Gallery

Start here

Navigation into the creator’s own docs — we don’t rewrite the guide, we route you to the source.

  1. 1.Read the official documentation site(The repository links to gaggiuino.github.io. Start there, not in the code. It walks through the design, the wiring, and what you are actually changing inside the machine.)
  2. 2.Join the Discord or subreddit(The community is where you find current part numbers, board vendors, and real answers to 'will this transducer fit my machine'. Do not buy anything until you have asked.)
  3. 3.Decide on a board source(Order a PCB or kit from one of the approved official suppliers listed in the documentation, or source the components yourself from the BOM. Ask in the Discord which board revision suits your machine.)
  4. 4.Source a compatible donor Gaggia Classic or Classic Pro(Used machines are fine if the boiler and pump work. Check the model ID against the compatibility table first: the Gaggia Classic V2 (2015-2018, SIN035U RI9403) is not compatible, and Pro Eco, Evo Pro and E24 models need extra mods such as a power switch mod or a 10-12 bar OPV.)

Resources

Documentation, files and community threads for this build — we link straight to the original sources and never rehost the creator’s files.

KNOWN ISSUES

  • Buying the wrong pressure transducer. The most common mistake happens before the build starts: ordering a transducer with the wrong pressure range, thread size, or electrical connection. The community wiki lists known-good part numbers. Use those, or ask before you order. A transducer that does not fit will waste a week waiting for the replacement.
  • Assuming the build is plug-and-play. This is not a kit with numbered bags. You are sourcing components from the BOM, soldering a PCB, and integrating it into a machine that was never designed to be modified. If you have never done a project where the instructions say 'solder this to that', the learning curve is steep.
  • Underestimating the enclosure work. The boards and screen need to mount somewhere. The stock Gaggia case is not designed for a touchscreen. Most builders either 3D print custom panels or drill the existing case. Both take longer than the electronics.
  • Not isolating mains properly during testing. The single most dangerous moment is the first power-on after rewiring. If you have left a live wire exposed, forgotten to insulate a solder joint, or misread the wiring diagram, the fault will show up when you plug it in. Test continuity with a multimeter before you apply power, and do the first power-on with the machine on a wooden surface, not a metal bench.
  • Expecting the first flash to work. Firmware issues are common. The screen may not initialise, the temperature reading may be wrong, or the pressure graph may flatline. Budget time for debugging. Most problems are a loose connector or a flipped thermocouple polarity, but finding them takes patience.
  • Ignoring maintenance. The mod does not remove the need to descale and backflush; Gaggiuino even includes a descale program to help.

Does this void the warranty on the Gaggia?

Yes, completely. You are disassembling the machine, removing the stock thermostat and wiring, and installing custom electronics. Gaggia will not service a modified machine.

Can I do this if I have never soldered before?

Not recommended. The PCB has surface-mount components and the mains wiring has no margin for error. If you want to learn to solder, start with a kit that does not involve mains voltage or pressurised water. If you are determined to build Gaggiuino as your first project, buy a pre-assembled board from a community vendor and focus on the mechanical integration and wiring. That is still challenging but it removes the soldering risk.

How much does it actually cost?

The project does not publish a total. Your cost is the donor machine (used is fine if boiler and pump work), a PCB or kit and printed parts from an approved supplier or sourced yourself from the BOM, the screen or headless interface, and any optional scales. Price the BOM in your region before you start.

Is there a kit I can just buy?

Yes. The documentation lists approved official suppliers for PCBs, kits and 3D-printed parts. You still source the donor machine yourself, and you can alternatively order every component from the BOM and print the parts from the design files.

What is the one thing most likely to go wrong?

The docs do not single out one failure. The two places to be careful are mains wiring (the docs warn about shorts and ask you to keep electronics in their housings or on a non-conductive surface before power-up) and the pressure transducer connection, which uses the specific fittings and flat gasket listed for your machine. Check for leaks with the panels off before you close everything up.

Community builds

No community builds yet — be the first, we feature the best ones.

Discussion1

FROM THE COMPAREE TEAM

Pressure profiling and live telemetry are usually high-end features — and this mod brings both to the Gaggia Classic. What would you pull first once the build is done: a slow-rising profile for light roasts, or a declining-pressure shot to see what the hype is about?

CompareeTEAM1mo agoedited

Practical notes from our verification: the GitHub repository itself is small — README, licence and releases with firmware binaries — while the build documentation, wiring diagrams and parts list live on the project site, gaggiuino.github.io. The licence is CC BY-NC 4.0, so the project is free for personal use but not for commercial resale. The docs list approved official suppliers for PCBs, kits and printed parts, which is the safest place to start. There are no official build videos; community videos are collected on the docs' Community Media page. Check the compatibility table before you buy a donor machine: the Gaggia Classic V2 from 2015-2018 is not supported, and some newer Pro models need extra mods. Use the transducer fittings and gasket the BOM lists for your model, and leak-test with the panels off. The build is genuinely hard, but the result is a Gaggia Classic with pressure profiling and live telemetry. Correction (4 October 2026): we re-checked this page line by line against the project's own repository, documentation and videos, and fixed errors in earlier versions.

Zer0-bit and contributors

Gaggiuino started as a personal project to bring pressure profiling to the Gaggia Classic and grew into one of the most active open hardware communities in home espresso. The design is now maintained by multiple contributors, with active development on firmware, board revisions, and documentation.

GitHub

Star the project on GitHub

DISCLAIMER

  • Comparee is not the author of the projects featured here. All rights to each project belong to its creator — every page links to the original source, and we never host creators’ files.
  • Information is provided without warranty and may become outdated as projects evolve. Prices are indicative bands only — always check the creator’s parts list for current costs.
  • Building and operating any project is at your own responsibility. Protective equipment, safe workshop practice and compliance with local regulations are the builder’s responsibility.
GitHub repo