compareeHub

YOU CAN REBUILD A CHEAP ESPRESSO MACHINE INTO ONE THAT BEHAVES LIKE THE MULTI-THOUSAND-DOLLAR ONES

Rebuild the Gaggia Classic into a machine with PID control, pressure profiling, live shot telemetry and programmable profiles — the features that separate thousand-dollar machines from hundred-dollar ones.

by Zer0-bit and contributors

FULL CAD BOM FIRMWARE DOCS

HomeOpen-hardware

difficulty
●●●●●
time
several weekends
license
NOASSERTION
repo
repo ACTIVE2,641 stars

WHAT YOU’LL NEED

  • 3D printer + filament — printable parts — files are in the repo
  • Electronic parts — full list with part numbers in the repo BOM
  • Dev board / microcontroller — runs the project firmware

Partner

Reach your Pi from anywhere — Remote desktop to the machine running this build — no port forwarding, works right from the browser.Try Getscreen.me
1

COMPAREE VERDICT

Gaggiuino turns the Gaggia Classic — the entry-level machine that costs a few hundred dollars — into one with the control features of machines costing several thousand. After the mod you get PID temperature stability, pressure profiling across the shot, programmable brew recipes, live telemetry on a colour touchscreen, and shot weight tracking via connected scales. It is a genuine engineering project, not a plug-in accessory. You open a mains appliance, solder a custom PCB, mount a pressure transducer into the brew path, rewire the pump and boiler, and flash firmware onto a microcontroller. The project is honest about the risk: you do this without any safety certification and entirely at your own liability. The barrier most people hit is not the soldering — it is the confidence to work inside a pressurised, mains-powered device. 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 community is one of the most active in home espresso. The repository contains no licence file, so the legal status for commercial use or derivative work is unclear. For personal use, everything you need to build it is published. The result is a machine you understand completely, and one that pulls shots most people associate with equipment costing five times as much.

NOT IN THE REPO

  • —Complete PCB designs (Gerbers and KiCad files), firmware, step-by-step assembly guide, and wiring diagrams are all in the repository.
  • —No licence file is present in the repository. The code and designs are published but the legal status is unclear.
  • —This is a full rebuild of a mains-powered appliance. You solder, mount sensors into pressurised hydraulics, and rewire the machine's controls.
  • —The project states explicitly that you do this at your own risk. There is no safety certification and no liability is accepted.
  • —Active community on Discord and Reddit with hundreds of completed builds. Troubleshooting support is strong.
  • —No official kit exists. You source the donor machine, PCB, components and sensors separately. Several community vendors sell boards; the project does not endorse any of them.

Can I build this?

PrintCustom enclosure parts and board mounts (STLs in repository). The build works without them but the finish is better with.
BuyGaggia Classic donor machine (used machines work fine if the boiler and pump are sound), custom PCB (order Gerbers or buy from a community vendor), ESP32 microcontroller, pressure transducer, thermocouples, SSRs for pump and boiler control, Nextion or similar touchscreen, and either Acaia-compatible scales or a DIY load cell setup. No official BOM — the community wiki lists current part numbers.
ToolsSoldering iron, multimeter, screwdrivers, spanner set for hydraulic fittings, and ideally an oscilloscope for debugging if the first flash does not work. Firmware flashing needs PlatformIO or Arduino IDE.
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.
Cost$$$ — dominated by the donor machine (£200–400 used, £400–600 new), the PCB and components (£100–200 depending on whether you order bare boards or buy from a community vendor), and the scales if you go with Acaia-compatible models (£100–300). Total cost commonly runs £500–900, though a careful secondhand build can come in under £500.
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

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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(You can order bare PCBs from the Gerbers and solder the components yourself, or buy a pre-assembled board from a community vendor. The project does not endorse any vendor. Ask in the community which ones currently ship and which part revisions they are using.)
  4. 4.Source a donor Gaggia Classic(Used machines are fine if the boiler and pump work. The thermostat and stock wiring will be replaced anyway. Check which generation you have — the wiring differs slightly between the original, the 2015 refresh, and the 2018+ models. The docs cover all three but you need to know which you are working on.)

Resources

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

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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 the descale and backflush requirements. Once the mod is done, the machine still needs the same maintenance as before. The pressure profiling and PID control do not eliminate scale buildup or coffee oil in the group head. If you do not backflush regularly, the transducer will read incorrectly and the profiles will drift.

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?

Commonly £500–900 total, depending on whether you buy a used or new donor machine and whether you order bare boards or buy pre-assembled. The Gaggia itself is £200–600, the electronics are £100–200, and good scales add another £100–300. A careful build using a secondhand machine and basic scales can come in under £500. A new machine with Acaia Lunar scales will push past £900.

Is there a kit I can just buy?

No official kit exists. Several community members sell pre-assembled PCBs, but the project does not endorse any of them and the vendors change over time. You still source the donor machine, sensors, screen and scales separately. Ask in the Discord for current recommendations.

What is the one thing most likely to go wrong?

A leak at the pressure transducer fitting. If the thread sealant is not applied correctly, or the transducer is over-tightened and cracks the adapter, you will get a high-pressure water spray when the pump runs. It is not dangerous if you are watching, but it will soak the electronics and the counter. Test the hydraulics with the panels off and a towel ready 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 the features that separate thousand-dollar machines from hundred-dollar ones — 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?

CompareeTEAM11d ago

Practical notes from our verification: the repository contains complete PCB files, firmware, and wiring diagrams, but no licence file — the legal status is unclear, though everything is published. There is no official YouTube channel; the walkthroughs that exist are community-made. The single biggest trap is not the soldering or the firmware — it is the pressure transducer fitting. If you do not use thread sealant correctly or you order a transducer with the wrong thread pitch, you will get a high-pressure leak the first time the pump runs. Ask in the community which transducers currently fit before you order. The build is genuinely hard, but hundreds of people have done it, and the result is a machine that holds its own against equipment costing several thousand.

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