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HOW PULSED BLUE LEDS LET A CAMERA SEE INSIDE A WELDING ARC

A welding arc is too bright to film through — this commercial system out-shines it with kilowatt pulses of blue LED light instead of filtering it down.

by Ben Krasnow

FULL CAD BOM FIRMWARE DOCS

WorkshopScience

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WHAT YOU’LL NEED

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COMPAREE VERDICT

This is not a build project — it is a principle worth understanding. In the video, Ben Krasnow of Applied Science demonstrates Kron Technologies' Helios welding visualization system, a commercial camera-and-lighting product the manufacturer sent him. The trick is to out-shine the arc rather than filter it down: an array of narrowband 450 nm royal-blue LEDs is pulsed to about a kilowatt only while the camera shutter is open, and a notch filter on the camera passes just that wavelength, so the broadband arc contributes very little. The result is footage where you see the molten pool, droplets and the bead in remarkable detail, and he also films burning magnesium and underwater laser cutting. What is not here: a parts list, wiring, firmware, filter specifications or a build guide, because the hardware is a commercial product. If you want to reproduce the idea yourself, the hard parts are high-current LED pulsing with cooling, a matching narrowband filter, and shutter-synchronised timing — and you would be designing all of that from scratch.

GOOD TO KNOW

  • —This is a filmed method, not a repository or design file.
  • —The video demonstrates Kron Technologies' commercial Helios system and explains the principle.
  • —No parts list, PCB files, firmware, CAD or wiring diagrams exist.
  • —A DIY version would need high-power pulsed LEDs with cooling, shutter synchronisation, a matching narrowband filter and a high-speed camera — all sourced and designed yourself.
  • —No licence — this is a demonstration of a technique, not distributed design files.
  • —The video shows a commercial welding-visualization system (Kron Technologies Helios), not a homemade reproduction.

Parts to buy

5 items

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

  • For a DIY attempt: a high-speed camera with external syncFind
  • High-power narrowband LED array with cooling and a pulse driverFind
  • Matching narrowband filterFind
  • Mounting hardwareFind
  • WelderFind

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Can I build this?

Printnothing required
BuyFor the demonstrated result: the commercial Helios system with a high-speed camera. For a DIY attempt: a high-speed camera with external sync, a high-power narrowband LED array with cooling and a pulse driver, a matching narrowband filter, mounting hardware, and a welder.
Toolsbench tools, soldering station, optical rail or rigid mount, multimeter, oscilloscope for sync verification
Skillshigh-speed imaging, camera/flash synchronisation, optical filter selection, electronics prototyping, welding — this is not a first project
Timeseveral weekends to source parts, build sync circuit, mount optics and verify timing
Cost$$$ — a high-speed camera and kilowatt-class pulsed lighting; the video gives no price.
SafetyWelding arc produces UV and intense visible light — normal welding PPE required. The pulsed LED array is intense enough to heat a sheet of black plastic in front of it, so do not look into it. Do not look at the arc or the lighting without proper protection.

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

Videos

Creator’s build video

Applied Science demonstrating Kron Technologies' Helios welding visualization system: how it works, then footage of welding, burning magnesium and underwater laser cutting.

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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.Watch the Applied Science video (The only documentation is what is shown on camera — components visible on the bench, filter in front of the lens, sync setup.)
  2. 2.Understand the high-power pulsed narrowband LED lighting(The demonstrated system uses an array of 450 nm royal-blue LEDs pulsed to about a kilowatt and water-cooled; peak brightness in the filter's passband must beat the arc.)
  3. 3.Select a narrow bandpass filter(The filter's centre wavelength and bandwidth determine what you pass from the flash and reject from the arc. This is the core of the method.)
  4. 4.Build or buy camera-to-flash sync(The LED pulses must line up with the camera's very short exposure; the commercial system does this for you, a DIY version would not.)

KNOWN ISSUES

  • Lighting without enough peak power in the filter's passband — if the pulsed light does not out-shine the arc while the shutter is open, the method fails.
  • Choosing a filter with the wrong centre wavelength or bandwidth — the arc has a broad spectrum and the flash must dominate in the region you pass.
  • Camera sync failure — if the flash fires outside the shutter window, you record darkness or a dim frame.
  • No parts list or schematic exists — the video demonstrates a commercial product, so any DIY version starts from the principle alone.
  • Underestimating the difficulty — this requires high-speed imaging knowledge, optical filter selection and electronics prototyping, not assembly from a kit.
  • Looking at the welding arc without proper welding eye protection — it emits intense UV and visible light. The pulsed blue LEDs are a different case: in the video they run at a very low duty cycle, but a home-built driver with longer pulses could make them far brighter, so do not stare into them.

Is there a repository with design files?

No. The video demonstrates a commercial product (Kron Technologies' Helios), so there are no design files. It explains the principle only.

What filter specifications do I need?

The system in the video uses 450 nm royal-blue LEDs and a matching narrowband filter on the camera, so the camera mainly sees the LED light and only a thin slice of the arc's broadband light. The video gives no filter part number.

Could a camera flash do the same job?

The system in the video uses LEDs, not a camera flash: an array of narrowband LEDs pulsed to about a kilowatt only while the shutter is open, with water cooling. Kron also supplies white LEDs for colour footage, but without the narrowband filter they do much less to suppress the arc.

How fast does the flash need to be?

In the video the camera runs at about 1,000 frames per second with a very short exposure, and the LEDs fire only during that exposure — a duty cycle of roughly one percent — which lets each pulse reach about a kilowatt.

Is this cheaper than an industrial welding-process camera?

Unknown — the video shows the commercial Helios system and gives no price. A DIY version would need a high-speed camera, high-power pulsed LEDs with cooling, a matching narrowband filter and shutter sync, none of which is documented.

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Discussion1

FROM THE COMPAREE TEAM

Industrial welding-process cameras are laboratory equipment, and this one beats the arc with pulsed narrowband LEDs and a matching filter. What would you film first with a setup like this — welding, plasma cutting, or something else?

CompareeTEAM1mo agoedited

Practical notes from our verification: the source video is Applied Science demonstrating Kron Technologies' Helios welding visualization system — a commercial camera-and-lighting product the manufacturer sent for review, not a homemade rig — so there is no repository, parts list or build guide. What the video does explain is the principle, and that is the part worth learning: an array of narrowband 450 nm royal-blue LEDs, a notch filter on the camera that passes only that wavelength, and LED pulses of roughly a kilowatt synchronised with very short exposures (around 10 microseconds at about 1,000 frames per second), so the lighting outshines the broadband arc only while the shutter is open. The LEDs in the demo are water-cooled. If you wanted to reproduce the idea yourself, the hard parts would be high-current LED pulsing, a matching narrowband filter and shutter-synchronised timing — none of which the video documents as a build. 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.

Ben Krasnow

Ben Krasnow runs Applied Science, a YouTube channel about bench science, instruments and process visualisation. In this video he demonstrates Kron Technologies' Helios welding visualization system, which the manufacturer sent him, and uses it to film welding, burning magnesium and underwater laser cutting.

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