YOU CAN BUILD THE €1,330 VACUUM GAUGE FOR €70
A vacuum gauge you can build for seventy euros instead of buying for thirteen hundred, and actually repair when it breaks.
by Julius Bernd Zimmermann and Marcus Herbig
ScienceOpen-hardware
Built withArduino3D printing
- difficulty
- ●●●●○
- time
- a weekend-plus
- license
- CC-BY-4.0
- repo
- repo FINISHED0 stars
●●●●○ · a weekend-plus · CC-BY-4.0 · 0 stars · repo FINISHED
WHAT YOU’LL NEED
Jump to section
COMPAREE VERDICT
OpenVac is the real thing: a peer-reviewed Pirani vacuum gauge for rough-to-fine vacuum that costs about seventy euros instead of over a thousand. The authors are chemists who needed a gauge they could fix for Schlenk-line work, and the validation data is in the paper, including a sealing test of the sensor connection (leak rate 9.2 × 10⁻³ mbar/min). The Pirani principle is elegant: heat a wire, measure how fast the remaining gas cools it — thinner air means less cooling. A Heimann HVS04 sensor sits in a Wheatstone bridge, an ADC digitises it, and an ATtiny84 sends the pressure to a small OLED; the whole thing runs on a 9 V battery. The build is approachable for anyone who has soldered a kit, and the firmware is an Arduino sketch flashed through the Arduino IDE. For the most accurate readings you calibrate against a reference gauge with the provided Python script, but the paper also gives a standard calibration that works when you cannot. If you run a vacuum pump, freeze dryer or Schlenk line and you are tired of paying repair quotes that exceed the instrument's value, this is worth the weekend.
IN THE REPO
GOOD TO KNOW
- —Complete design files, schematics and firmware are published on Zenodo under CC-BY 4.0; the bill of materials is in the HardwareX paper.
- —Peer-reviewed HardwareX paper includes validation data, leak rate measurements and calibration procedure against a reference sensor.
- —No GitHub repository — files are on Zenodo; the firmware is an Arduino sketch (source only) that you compile and flash with the Arduino IDE.
- —Two small boards (power/display and sensor) designed in KiCad and joined by pin headers so either can be replaced; the ATtiny84 is the through-hole -20P version, and the sensor connection is sealed with epoxy.
- —Calibration is manual and requires access to a reference vacuum gauge or controlled pressure points.
- —Commercial use is permitted under CC-BY 4.0 but you must attribute the authors.
Parts to buy
8 itemsFrom our check of the build. Exact quantities and part numbers are in the creator’s BOM.
Can I build this?
Build at your own risk. Projects involve tools, electronics and sometimes mains voltage — follow the creator’s safety notes.
More builds like this
All projectsGallery
Start here
Navigation into the creator’s own docs — we don’t rewrite the guide, we route you to the source.
- 1.Read the HardwareX paper (The methods section contains the calibration procedure and validation setup — read it before ordering parts)
- 2.Download design files from Zenodo(DOI 10.5281/zenodo.15728968 — includes the KiCad projects for both boards, the Arduino firmware source, the Python calibration script and the 3D-printable enclosure files; the bill of materials is in the paper.)
- 3.Order PCBs and components(BOM is in the supplementary material — verify Pirani sensor module availability and lead time first, it is the long-pole item)
- 4.Assemble and flash firmware(Solder the two boards, seal the sensor connector with epoxy, then flash the ATtiny84 using an Arduino Nano as programmer)
- 5.Calibrate against a reference or known pressure points(The paper describes calibration at atmosphere, rough vacuum and fine vacuum — skipping this step gives you a display that lights up but numbers you cannot trust)
KNOWN ISSUES
- The Pirani sensor module is the one component you cannot substitute without reworking the firmware — verify availability and exact part number before starting.
- The standard calibration gets you usable numbers, but deviation grows toward the top of the range; if you need accuracy there, do the individual calibration against a reference gauge.
- Sealing the gas connector to the sensor board is the critical step: the authors use two-component epoxy and let it cure for about 24 hours; a poor seal shows up as a leak, so leak-test the finished gauge as the paper does.
- The paper assumes you already have a vacuum system to measure. If you are building the gauge to learn about vacuum, you still need a pump, chamber and fittings.
- Leak rate validation (0.0092 mbar/min) was done on a specific test rig. Your system's leak rate will depend on your own seals and fittings, not the gauge.
- Flashing the ATtiny84 needs a programmer — the authors use an Arduino Nano as ISP with the ATTinyCore board package in the Arduino IDE; set that up before you solder the chip in.
How does this compare to a VACUUBRAND or WELCH gauge?
The paper compares OpenVac's readings against a commercial gauge: individually calibrated units track it closely, the standard calibration deviates more but is usable. The commercial units it lists cost about 800 to 1,330 euros and are hard or impossible to repair; OpenVac's two boards can be replaced separately when one breaks.
Can I skip calibration?
You can start with the paper's standard calibration, which the authors found reliable enough when an individual calibration is not possible. For the best accuracy, calibrate your unit against a reference gauge with the provided Python script.
What vacuum range does it cover?
It is a Pirani gauge for rough to fine vacuum: the authors target 1 mbar down to 0.0001 mbar, and verified the standard calibration mainly between 1 and 0.1 mbar, the range that matters for Schlenk lines. It is not an ultra-high vacuum gauge.
Can I use this commercially?
Yes — the CC-BY 4.0 licence permits commercial use as long as you credit the authors. Read the licence terms on the Zenodo page.
Is the firmware open source?
Yes — source code is in the Zenodo deposit. It is written for ATtiny84 and uses SPI for the sensor, I2C for the display.
Community builds
No community builds yet — be the first, we feature the best ones.
Discussion1
FROM THE COMPAREE TEAM
Commercial vacuum gauges listed in the paper cost roughly 800 to 1,300 euros, this one about 70 euros in parts, and the authors measured a leak rate of 0.0092 mbar per minute on their unit. If you have built a Pirani gauge before, what tripped you up during calibration?
Julius Bernd Zimmermann and Marcus Herbig
Zimmermann and Herbig are researchers at the Department of Inorganic Chemistry, Technische Universitat Bergakademie Freiberg, Germany. They built OpenVac for Schlenk-line work because commercial vacuum gauges cost 1,000 to 1,300 euros and are often hard or impossible to repair. The project was published in HardwareX, peer-reviewed and validated against a commercial gauge.
Keep building — related projects
Same category or platform, picked by how close they are to this build.
FULL CADYou can build the 10,000-dollar lab shaker for 169 dollars
ScienceFor intermediate builders
FULL CADYou can build the 5,000-dollar machine that counts cells, for 165 dollars
ScienceFor advanced builders
FULL CADYou can build the 30,000-dollar machine that separates whole chromosomes, for 850 dollars
ScienceFor expert builders
FULL CADLabs pay 18,000 dollars for a 96-channel pipette. He built one for 250 dollars
ScienceFor advanced builders
FULL CADYou can build a laser scanning microscope from a dead Blu-ray player
ScienceFor advanced builders
FULL CADPUMA: a 3D-printed benchtop microscope that takes professional optics up to 1000x oil immersion
ScienceFor advanced builders
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.
CompareeTEAM23d agoedited
Practical notes from our verification: the design files live on Zenodo (DOI 10.5281/zenodo.15728968), not GitHub, and the firmware is an Arduino sketch that you burn onto a through-hole ATtiny84 using the Arduino IDE with an Arduino Nano as programmer, so no surface-mount soldering is needed. The parts come to about 70 euros, and the device runs on a 9 V battery. The paper is unusually honest: its standard calibration deviates more from a commercial gauge than an individually calibrated unit, but the authors say it is precise enough when individual calibration is not possible, and the sensor is split into two parts so a broken one can be replaced cheaply. The single biggest decision is whether you have access to a reference gauge. With one, you can do the individual calibration for best accuracy; without one, start with the standard calibration and know its limits. 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.