[cowsaymoo]

The prototype came with a power supply that is set at 24V, 5A and consumes 90W when running. Not sure how the control circuits work but its pretty simply operated with a 3P2T switch for 650nm/Off/850nm. Each module contains a fan cooled array of LEDs behind a plastic lens. I think it has some thermal shut off protection circuit as well.

I just dug out the spec sheet for the other device and you're right. It says "LED Power Class 1800W", but lists power consumption as 350W.

I really like it's potential to improve the right kind of symptoms when applied correctly and I'm also wary of people with bottom line incentives filling in any scientific uncertainty with miracle cures. But I agree, it's definitely worth using. It's a one time purchase with no side effects, so the worst case risk is just disappointment.

[throwway120385]

It would probably be 1800W continuously but is pulsed and the duty cycle probably limits the power to 350W.

[b112]

Can light penetrate the skull bones though?

[lukeinator42]

yes, and you can even use infrared spectroscopy to infer brain activity via the bold signal: https://en.wikipedia.org/wiki/Functional_near-infrared_spect...

[ankitml]

infrared, yes. Although depends on skin colour wrapping the skull. Melanin absorbs everything under the sun. It has very high absorption of UV but somewhat absorbs infrared too in this range of frequencies. Darker the color of skin, higher the melanin and higher the absorption by skin.

[energy123]

Yes

[CyberDildonics]

Light is anything in the spectrum visible to people, with the exception of infrared being called light. What evidence do you have that this is true?

[kjs3]

Not wanting to violate the "don't tell people to google the obvious, no matter how condescending they're being", I googled the obvious for you.

https://link.springer.com/article/10.1007/s10103-024-04024-z

To achieve a neuroprotective effect, PBM must overcome several barriers, including bone tissue, a complex structure with variable optical properties

https://www.spiedigitallibrary.org/journals/neurophotonics/v...

Photobiomodulation (PBM) is a near-infrared (NIR) light-based therapy technique and has shown therapeutic effectiveness for various neuropsychiatric disorders, including MDD. The transcranial PBM (t-PBM) technique delivers NIR light through the scalp and skull.

https://www.frontiersin.org/journals/neuroscience/articles/1...

Near-infrared spectroscopy in the brain is made possible by the relative transparency of biological tissues (including bone) to light for infrared wavelengths ranging from 650 to 925 nm.

[CyberDildonics]

https://www.frontiersin.org/journals/neuroscience/articles/1...

Penetration of light from an 820 nm gallium-aluminum-arsenium laser diode through a sample of fresh human skin. Data extrapolated from data presented in Kolari (25) and shown in the blue columns. A line of regression is shown by the black dotted line. The regression line indicates that light from a low-power laser diode can penetrate less than 2.2 mm into human skin.

This says that a 820nm laser penetrate 2.2mm into human skin. That is 0.08 inches. That is about the width of a groove on the top of your finger. How does that square with saying that it could go through skull bone that is 3.5x as thick while being more dense than tissue?

[kjs3]

I assume you had a cut-n-paste failure with that link. I think you meant https://www.frontiersin.org/journals/neurology/articles/10.3..., which I assume you picked because the title. It is an interesting article, should you ever decide to read it beyond cherry picking the caption from 'Figure 2'. But TL;DR: It doesn't say what you apparently think it says. The author is questioning the therapeutic value of low power infrared light therapy, and demonstrating what is required for medical effect. He is not questioning whether or not infrared light can penetrate skin and bone, because it does. For example:

We have demonstrated that our multi-watt NIR data delivers an estimated 1.65–3.7 J/cm2 to a depth of 30 mm. As shown above, this is within the biologically meaningful fluence range (1, 2, 4, 6, 47) and is more than 100-fold greater than the fluence delivered by an LED system or by a low-power infrared light system according to the findings of the authors cited above (7, 18, 21, 37, 38, 48).

and

Patients receiving 10–20 treatments of multi-watt infrared light, each lasting approximately 20–30 min, have experienced significant, and often, dramatic improvements (47, 48). The fluence of combined 810 and 980 nm light delivered during each of these treatments was, on average, 81 J/cm2/treatment. Correcting for forehead skin, skull, and 1 cm of brain tissue, this delivered a fluence of fluence of 0.41 J/cm2 to the neurons 1 cm below the cortical surface.

The authors paper listed as citation #4 (https://www.tandfonline.com/doi/full/10.2147/NDT.S78182#medi...) has more detail on his methods, and the abstract sums it up pretty well:

NIR in the power range of 10–15 W at 810 and 980 nm can provide fluence within the range shown to be biologically beneficial at 3 cm depth. You can't ELI5 more than that.

Understanding does take work, and given your posting history of mostly low effort negative snark, I probably spent more time than I should have. But it was an interesting diversion into something I otherwise wouldn't have known.

[Filligree]

Radio waves do with no trouble. Blue does not at all. Everything between is on a sliding scale; there are no qualitative changes until you get to ionising radiation.

Though there’s a bit in the middle where it matches the resonant frequency of water molecules, yes.