The image on the right shows one of the medical loupes with LED light. They are very useful for detailed work with precision optical instruments for surgery. The price is also tens of thousands of yen.

I thought I would imitate this. I don't need a loupe, but an LED would help with precision work.

It should be detachable from glasses and lightweight.
Batteries should be separate, of course. Cables may be cumbersome, but lightweight should be a priority in this regard.



The right image shows the attachment part of the sunglasses that can be attached to and detached from the glasses. The lenses of the sunglasses were thrown away. I found such a thing for 100 yen. There is no way not to use it.

Since we are using a PowerLED, we would like to have a constant-current circuit if possible, but it would be too heavy to put on an attachment with a LED. A semiconductor is a very small thing.

PowerLED is sufficient for 100lumen/1W, so I decided to drive it with a single resistor, assuming 5.0V, which is likely to be the standard power supply.

The reflector was added because the light distribution was too wide for the purpose when using only LED. Perhaps a collimator that can narrow down the light distribution would have been better.

Heavy heat sink cannot be used. No matter if it is a lightweight small heat sink, it is too heavy.
A sheet of perforated metal was added to the back side of the clamping bolt to release the heat transmitted from the bolt. It's not much, but it makes a big difference.

I didn't weigh it, but it turned out to be pretty lightweight.



It is an exaggeration to say modularization, but each of these attachments and power supplies can be used as a general-purpose item.
Or, actually, there are several power supplies that can be used universally, so use those.

The two power supplies used in the left image; they are 5 V, so an extra portable AC adapter can be used, but the battery type is more convenient, as the power supply can be placed in a pocket.
The two AA type on the left has a circuit to boost the voltage to 5.0V. It was made as an emergency power supply in the era of mobile phones, and can also output USB.
The four AA type power supply on the right side is a stabilized power supply with variable output voltage. It was made as a power supply for a vaporizer and is also useful as a power supply for experiments in electronic construction.

One might say that if we are talking about modularization, we should use general-purpose USB for connectors, but we have been using JIS-standard plugs as connectors for this type of equipment since before USB became widespread, and we cannot change that now.
The point is to avoid specializing the power supply by adding circuits for LED.

Since we have a lightweight, compact, general-purpose power supply, it would be nice to have a lamp that can be used with it.
The power supply has an output of 5.0 V and a variable stabilized power supply, so it can be used universally with LED lamps that incorporate a constant-current circuit.


However, if a voltage exceeding Vf is applied, the excess will be used to generate heat in the transistor.



I've been using them uniformly for a long time now, so the plugs can't be changed now.

If the power supply and lamp are not connected by a cable, but the lamp is supported by a plug, it becomes an integrated lamp simply by plugging it in. In short, I can hold it with one hand.



One with 100 lumen and one with 200 lumen were made.
I've used it when the light bulb in the bathroom went out, for example, and it has more than enough light.

A one-coin shop product. I don't know why, but it seems to be a popular product there.
It is a large structure for this level of light output, and the system is designed to be lit by stretching it further.
It is powered by three AAA batteries, which are directly fed into the LEDs. As is common with Chinese products, there is not even a resistor. I did not measure the run time, but I guess it only lasts for about an hour.

For the record, it's a terrible product.

I modified it step by step, but when I used it with the AC adapter, not realizing that there was not even a resistor in it, the 6 LEDs broke one after another.
Finally, I made all the circuits myself, including the LED.



In the end, only the case was diverted. The excessively large case was discarded, however, and only the part that allows light to pass through was used. The battery box is a nice side of the case.
A jack for AC adapter is installed to allow switching between dry cell batteries and AC adapter.
We were able to finish it much smaller than the original frame.

Circuit is the same as that of general-purpose LED lamp.

An one-coin shop product. Lights up when a person approaches. Cost-effective, even if only parts are used.

Since functionally similar products are sold at home centers for around 2,000 yen, there is no doubt that they offer excellent cost performance. I have actually used this product for more than a year, and it is very well made in terms of functionality. I would even use it as a trigger for a security camera.

Of course, it does not light up when it is bright. It does not light up even if it is only dimly bright. The adjustment in that area is also well done.



Unfortunately, it is battery-powered with three AAA batteries.
Of course, use with AC adapter



The body is unnecessarily large. It's not surprising that it's bigger because of the battery box in it.

Since it is used with an AC adapter, only the necessary parts were taken out and those were rearranged on the board.
It is quite small and lightweight, and can be fixed to walls and other surfaces with double-sided tape.



Some are waterproofed and mounted outdoors by the front door. When it rains, it may detect it as a temperature change, or malfunctions frequently, so we added eaves.



I suppose it would look better if it were re-fitted in a smaller case.

First, please see the following site, which shows the results of a clinical experiment that LED light can restore vision.
Optically Improved Mitochondrial Function Redeems Aged Human Visual Decline | The Journals of Gerontology: Series A | Oxford Academic

In summary,
The function of mitochondria in eye cells declines with aging, and this can be restored with LED light at a wavelength of 670nm. Mitochondria are like power plants, supplying energy for cellular functions.
It is the light at 670nm wavelength that activates the mitochondria. Subjects are exposed to this light for 3 minutes every morning. The output is 40 mW/cm2.

Researchers say that vision can be restored in people over the age of 40. Younger people don't have much loss of function, so it's unnecessary.



If I could do electronics, this is what I would want to build.
LEDs with a wavelength of 670 nm are available. It is possible to adjust the output power of 40 mW/cm2 at the ocular surface, but it is a hurdle to adjust it exactly.
Besides, irradiating for 3 minutes every morning is also a hurdle for a lazy person (lol).


Researchers have also suggested that this item could be marketed (right image).
It has even been spotted being used in first class on international flights. Is it a one-off a piece?



Being a sloppy person, I decided to make this a part of my life.
I used it as a bedtime reading light.

The eye will be exposed to the light reflected from the paper. Although the light source is powerful enough, the output of light that the eye receives is much weaker than "40 mW/cm2". By using it over a long period of time, we could try to restore vision within a safe range of output.


I don't know if it restores eyesight as the researchers boldly claim, but when I started using it, my eye strain was clearly gone. I can feel that it is quite effective without any special tests.


The circuit is the same as that of general-purpose LED lamps and is operated with an AC adapter. 2 lamps are placed side by side with a switch attached to each, each having a high output of 200 lumens of illumination. A collimator with a half angle of 10 degrees is attached to the lamps. Of course, it is not for direct viewing.
Simply mounted on the pillow side wall of the bed.


In the left image, the leaked light only stains the surroundings, but the collimator's irradiated area is illuminated by strong light.



The wavelength of the above LEDs is 680-700 nm, which is slightly longer than 670 nm. Although we were still able to confirm the effect, there is nothing better than using a more precise 670nm LED. It was created with LEDs for plant growth, which have a wavelength of 670 nm.
The circuit is also driven by a constant-current circuit using an OP amplifier and MOSFETs, which facilitates higher efficiency and output.



The current to the LEDs should be controlled individually, but here two lights are connected in series.
Since the Vf of a single LED is 2.0 to 3.0V, if the supply voltage is greatly exceeded, the excess heat generated by the mosfet will result in a large loss.

As shown in the circuit diagram, the constant current circuit is controlled in two modes by a SW. The current can also be increased or decreased by fine-tuning the Vref of the OP amplifier using VR.
This Vref should also be as small as possible to minimize losses at R5 and R6.

Since it is not battery powered, losses are not a major concern, but I want to reduce heat generation by minimizing losses in each part.

As a side note, when soldering PowerLED to a special board, put a thin layer of solder on the board side beforehand. If you try to solder it suddenly, it may not adhere well. Solder in a short time because heat can easily escape.


I simply clipped it to the wall and used it as a reading light.
I did not notice much difference compared to the previous one. Slightly different color tones when compared in the image.

The previous one had a maximum of 400 lumens, this one has a maximum of 800 lumens. I use about 600 lumens. the TIR (collimator) is 10 degrees and is required for reading.

It is interesting that LED light for plant growth activates mitochondria in eye cells, and clinical trials on vision restoration have proven its effectiveness. 670nm wavelength light is a wonder.
As a side note, for plant growth, the 670nm wavelength light is used as the main light source in combination with blue LED light. Only 670nm wavelength light is used to restore eyesight.