YOU CAN BUILD THE INSTRUMENT STERILIZER THAT RUNS OFF A CAR BATTERY
Clinic sterilizers need stable mains power; this dry-heat one runs on 12 volts, so a car's cigarette-lighter socket or a solar-charged battery will do.
HealthOpen-hardware
Built withArduino
- difficulty
- ●●●●○
- time
- a weekend-plus
- license
- license not specified
- repo
- repo STABLE5 stars
●●●●○ · a weekend-plus · license not specified · 5 stars · repo STABLE
WHAT YOU’LL NEED
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COMPAREE VERDICT
David Hartkop built this after reading a World Health Organization report that 3 billion people live in rural areas without reliable electricity, and that surgical care is often out of reach there because sterilizers are too expensive and draw too much power. The Open Autoclave is a dry-heat medical instrument sterilizer that runs on 12 volts DC, so it can work from a car's cigarette-lighter socket or a solar-charged battery. It is not a pressure cooker: it is an insulated oven made from a stainless stock pot wrapped in ceramic fibre insulation and foil, with aluminium pizza-screen shelves heated by 40-watt 3D-printer cartridge heaters, and an Arduino that holds the temperature, counts the exposure time and logs the data. The repository has the parts list, schematic, drill templates, Arduino code, log sheets and a book-length manual, and the author's two-hour companion video walks through the build. The author verified sterilization with mail-in biological indicator strips and tells you to do the same. The book is released under CC-BY. The hardest part is not the build, it is the responsibility: if you use it on real medical instruments, you own the validation.
IN THE REPO
GOOD TO KNOW
- —The repository carries a complete parts list as a spreadsheet, the Arduino source code, wiring schematic, drill templates for the electronics box, exposure-time chart, run logsheets and photos of the finished unit.
- —There is a book-length PDF (181226_OpenAutoclaveBookDownload.pdf) and a build video on the creator's channel.
- —The repo has no licence file, but the build book is released under CC-BY (free to share and adapt, even commercially, with credit).
- —This is a dry-heat oven that runs at around 140-170 °C. The book explains how to verify sterilization with mail-in biological indicator strips, but if you use it on real medical instruments you are responsible for validation.
- —No CAD files are needed: the oven is built from a stainless stock pot, ceramic fibre insulation, aluminium pizza screens and 3D-printer cartridge heaters, with drill templates for the electronics box.
- —The design is for off-grid surgical instrument sterilisation in areas without reliable mains power, not a general-purpose kitchen pressure cooker.
Parts to buy
9 itemsFrom our check of the build. Exact quantities and part numbers are in the creator’s BOM.
- 12-quart stainless stock potFind
- Ceramic fibre insulationFind
- High-temperature foil tapeFind
- Aluminium pizza screens and a cookie sheetFind
- 12 V 40 W 3D-printer cartridge heatersFind
- Arduino with MAX6675 thermocouple module and K-type probeFind
- LCDFind
- 12 V automotive relay with MOSFET driverFind
- 8 A fuse and an electronics boxFind
Can I build this?
Build at your own risk. Projects involve tools, electronics and sometimes mains voltage — follow the creator’s safety notes.
Videos
Build an open-source off-grid medical instrument sterilizer
The creator's two-hour companion video to the Open Autoclave book.
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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.Read the Open Autoclave book (181226_OpenAutoclaveBookDownload.pdf) in the repository(Book-length walkthrough with safety protocols, parts list, assembly instructions and testing procedures)
- 2.Watch the full build video (Step-by-step assembly on the creator's channel)
- 3.Review the parts list spreadsheet and source components (The BOM is in the repository as a spreadsheet)
- 4.Flash the Arduino code and test the control circuit before final assembly (Source code is in the repository; test the relay and temperature sensor operation before you commit to drilling the pot)
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
- The repository has no licence file, but the book is CC-BY (credit the author); the Arduino code has no separate licence, so ask the author before redistributing modified code.
- If you intend to use this for actual medical sterilisation, you are responsible for validation, calibration and safety testing — the documentation provides protocols but you own the liability.
- The oven is a 12-quart stainless stock pot with the handles cut off, wrapped in ceramic fibre insulation, heavy foil and aluminium furnace tape. Keep all tape on the outside: the book warns never to put any tape inside the chamber or around its bottom edge, because the adhesive burns and contaminates your instruments.
- This is a 12 V DC design drawing about 8 amps: use a car's cigarette-lighter socket (engine running), a 12 V bench supply, or a solar panel charging a 12 V battery through a charge controller.
- The inner shelves are aluminium pizza screens bolted on legs, with 3D-printer cartridge heaters in aluminium blocks. Wire the cartridges exactly as the schematic shows: wrong wiring burns them out.
- The Arduino holds temperature and counts time, but you are responsible for understanding the exposure-time charts and choosing the correct sterilisation cycle for your instruments.
Can I use this for actual medical sterilisation?
The documentation includes safety protocols, exposure-time charts and testing procedures, but if you intend to use this for medical sterilisation you are responsible for validation, calibration and compliance with local health regulations. You own the liability.
What power supply do I need?
12 volts DC at about 8 amps. A car's cigarette-lighter socket works (keep the engine running during long runs), and a 12-volt bench supply is handy for testing. For solar, the book recommends a panel and charge controller charging a 12-volt battery; wiring a panel straight to the heaters only works in the manual, no-Arduino mode.
Is there a licence?
The repository itself has no licence file, but the book that documents the whole build is released by the author under CC-BY: you may share and adapt it for any purpose, even commercially, as long as you credit David Hartkop. The Arduino code is not separately licensed, so ask the author if you plan to redistribute modified code.
How long does a sterilisation cycle take?
The software ships set to 160 °C for 120 minutes, about 170 minutes in total from a cold start. The book's dry-heat chart ranges from 170 °C for 60 minutes to 140 °C for 180 minutes, and you can change the settings in the Arduino code.
Community builds
No community builds yet — be the first, we feature the best ones.
Discussion1
FROM THE COMPAREE TEAM
The documentation includes exposure-time charts and run logsheet templates, but if you intend to use this for medical sterilisation you own the validation and the liability. Would you build this for a clinic, or is the responsibility too high without institutional backing?
David Hartkop
David Hartkop started the Open Autoclave after reading a World Health Organization report that three billion people live in rural areas without reliable electricity, and that surgical care is often out of reach there because sterilizers are too expensive and draw too much power. He published the complete design so that clinics without a grid can build one.
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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.
CompareeTEAM1mo agoedited
Practical notes from our verification: this is a dry-heat sterilizer, an insulated stainless stock pot with 3D-printer cartridge heaters, not a pressure cooker, and the software defaults to 160 °C for 120 minutes, roughly three hours per cycle from cold. The repository has no licence file, but the book that documents the build is released under CC-BY, so you can reuse and adapt it with credit to the author. The author's two-hour companion video and the PDF book are unusually thorough. The single biggest decision is not technical: it is whether you are prepared to own the validation, for example with biological indicator strips, if this is for actual medical use. 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.