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YOU CAN BUILD AN NMR MACHINE - AND IT NEEDS NO LIQUID HELIUM AT ALL

Nuclear magnetic resonance without a room-sized superconducting magnet or a drop of liquid helium.

by Janvrin, Martin, Hancock, Varillas, Downey, Pellechia, Satme, Won (University of South Carolina)

FULL CAD BOM FIRMWARE DOCS

ScienceOpen-hardware

Built with3D printing

difficulty
●●●●●
time
multiple weekends
license
CC BY-SA 4.0
repo
repo FINISHED0 stars

WHAT YOU’LL NEED

1
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COMPAREE VERDICT

This is a serious build for someone with electronics experience. The University of South Carolina team replaced the liquid-helium superconducting magnet with a 0.5 tesla permanent-magnet assembly in a 3D-printed housing with 1018 steel field guides, and handles the analogue signal path on three custom boards: a control board, an impedance matching board and a coil board. The system measures T2 relaxation with a CPMG pulse sequence and, in the paper's validation, tracked copper sulfate in water with sensitivity around 900 parts per billion. The documentation is complete and the hardware files are all there, but this is not a weekend project. The magnets need careful, slow handling, the control board needs surface-mount reflow soldering plus a calibration step for the duplexer, and the data acquisition system is a separate purchase: the authors used a National Instruments PXI chassis with signal-generator and digitiser cards, which is not in the 1,650-dollar figure. They note a custom data acquisition system could replace it and greatly reduce cost. This is for someone who wants a teaching tool or a field instrument and is prepared to treat it as a multi-weekend research build, not a kit.

GOOD TO KNOW

  • —All CAD, PCB designs, code, and bill of materials are published on OSF under CC BY-SA 4.0.
  • —The BOM totals 1,650 dollars plus a data acquisition system, which is not included in that figure and adds significant cost.
  • —This is a time-domain NMR system — it measures T2 relaxation (CPMG), not full high-resolution spectra like a research-grade spectrometer.
  • —The permanent-magnet assembly uses a 3D-printed casing and steel field guides, and needs careful alignment (checked with a gaussmeter) to reach about 0.5 tesla.
  • —The licence is CC BY-SA 4.0, which permits commercial use but requires derivative works to carry the same licence.
  • —Strong permanent magnets are a physical hazard and require safe handling procedures.

Parts to buy

7 items

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

  • Permanent magnets and 1018 steel bars for the magnet assemblyFind
  • PCB fabrication and components for three boardsFind
  • Data acquisition systemFind
  • Glass sample tubesFind
  • Copper wire for the coilFind
  • 24 V supplyFind
  • Mechanical hardwareFind

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Can I build this?

PrintMagnet casing, magnet aligners and the coil tray — STEP/FreeCAD files provided for 3D printing
Buypermanent magnets and 1018 steel bars for the magnet assembly, PCB fabrication and components for three boards (control, impedance matching, coil), a data acquisition system (two signal-generator channels and a digitiser), glass sample tubes, copper wire for the coil, a 24 V supply, mechanical hardware
ToolsSoldering iron, solder paste and a reflow oven (the paper warns against using a heat gun), a 3D printer for the magnet housing parts, a gaussmeter for magnet polarity and field strength, an oscilloscope for testing, and LabVIEW for the control software
Skillselectronics assembly and debugging, mechanical assembly, basic RF circuit understanding, and patience for calibration. Prior NMR experience is not required but helps enormously.
Timemultiple weekends — PCB assembly and testing alone is a weekend, magnet assembly and calibration another, integration and software setup a third. First-time builders should plan for a month of evenings.
CostThe paper lists 1,650 dollars plus a data acquisition system. The authors used a National Instruments PXI setup (a PXIe-1083 chassis with two PXI-5421 generator cards and a PXI-5124 digitiser), which is a substantial separate cost; they note a custom data acquisition system could replace it and greatly reduce the total.
SafetyStrong permanent magnets are a serious physical hazard — they can crush fingers, shatter if they collide, and damage electronics or medical implants nearby. Follow all handling and storage procedures. No mains voltage or chemical hazards beyond normal electronics care.

Very strong magnets — keep away from pacemakers, cards and fingers.

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

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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.Download all files from the OSF repository (Start with the HardwareX paper PDF in the repository — it contains the full system description, calibration procedures, and results.)
  2. 2.Review the bill of materials and identify the data acquisition system(The BOM is a PDF in the repository. The NI PXI data acquisition system is not included in the 1,650-dollar figure.)
  3. 3.Order PCBs and source components(The boards are published as KiCad projects; export Gerbers from KiCad and use a board house that supports the specified stack-up. Some RF components may have long lead times.)
  4. 4.Machine or print the magnet housing(The CAD files (FreeCAD/STEP) are for the 3D-printed magnet casing and tray; the housing combines these prints with 1018 steel bars as field guides.)

KNOWN ISSUES

  • The data acquisition system is not included in the 1,650-dollar figure and is a separate significant purchase. Confirm compatibility before ordering anything else.
  • Strong permanent magnets require safe handling — they can cause serious injury if they snap together or shatter. Read the safety notes in the paper before ordering magnets.
  • Getting the magnet polarities wrong. The paper uses a gaussmeter to check each magnet's polarity during assembly and to measure the field so you can calculate the Larmor frequency for probe tuning, so treat a gaussmeter as required.
  • This is a time-domain NMR system, not a high-resolution spectrometer. It measures relaxation times, not chemical shifts. If you need full spectral resolution, this is the wrong instrument.
  • PCB assembly includes RF sections that are sensitive to layout and grounding. Follow the board notes closely and test each board in isolation before integration.
  • The probe has to be tuned before use: measure the magnet's field with a gaussmeter, calculate the Larmor frequency, and tune the coil and impedance matching board to it before installing the duplexer. Budget time for this after assembly is complete.

Can this replace a research-grade NMR spectrometer?

No. This is a time-domain system built around a CPMG sequence for T2 relaxation measurements. It does not have the field strength or resolution for chemical shift spectroscopy. It is a teaching tool and a field instrument, not a replacement for a high-field spectrometer.

What data acquisition system do I need?

The paper uses a National Instruments PXI system: a PXIe-1083 chassis with two PXI-5421 signal-generator cards and a PXI-5124 digitiser, controlled from LabVIEW. It is not part of the 1,650-dollar figure; the authors note a custom DAQ could replace it to cut cost.

Can I use a different magnet arrangement?

The field strength and homogeneity are critical to the measurement. If you change the magnet design, you will need to recalibrate everything and the results may not match the paper.

Is the licence compatible with commercial use?

Yes, CC BY-SA 4.0 permits commercial use, but any derivative work must also be released under CC BY-SA 4.0. If you need proprietary modifications, this licence will not work.

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Discussion1

FROM THE COMPAREE TEAM

The magnet reaches about 0.5 tesla with permanent magnets instead of liquid helium, and the housing is 3D-printed with steel bars. Would you build the NMR itself first, or start by sourcing the data acquisition hardware?

CompareeTEAM1mo agoedited

Practical notes from our verification: the OSF repository has the CAD, the KiCad projects for the three custom boards (control, impedance matching and coil), a PDF bill of materials and the LabVIEW code, and the full HardwareX paper is open access. There are no ready-made Gerbers — you generate them from KiCad yourself. The paper lists the hardware at 1,650 US dollars plus a data acquisition system, and it names the one it used (an NI PXIe-1083 chassis with two PXI-5421 cards and a PXI-5124 card), so price that separately before you commit. The magnet housing is assembled from 3D-printed parts and 1018 steel bars, and the instructions use a gaussmeter to check magnet polarity during assembly, so treat one as required. The system measures T2 relaxation with a CPMG sequence and was validated with copper sulfate solutions. There is no build video, so you are working from the paper and the files. 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.

Janvrin, Martin, Hancock, Varillas, Downey, Pellechia, Satme, Won (University of South Carolina)

The team built this system to demonstrate that time-domain NMR could be made accessible for teaching and field deployment without the infrastructure of a research lab. The design was published in HardwareX as a complete open-hardware project.

Web

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  • 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.
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