Introduction: DIY High Powered Red Light Therapy 660nm Flashlight Torch for Pain

About: Online Retailers of Red Light Therapy, Red Nightlights and Reading Lights, and Education

Can you make a high-powered DIY 660nm red light therapy flashlight torch for only $80? Some companies will say they have some special sauce or high-powered device, but even they are fudging their numbers to make them sound impressive.

A reasonably designed 660nm LED red light therapy flashlight can be great for targeted areas, skin health, pain or soreness, and possibly even inflammation. I use it for soreness around my thumb and wrist if I work on the computer and phone for too long. And often it is helpful for my sore knees and feet.

Unfortunately, due to improper measurement methods many companies are selling glorified flashlights with massively false advertised power outputs. Some high power flashlights and torches claim to deliver anywhere from 300 to 800mW/cm^2. This would actually deliver a therapeutic dose in literally seconds, and using it for too long would lead to negative effects or even burns. Obviously this is not the case. If the device or skin doesn't overheat quickly, then the power draw from these devices would defy the laws physics to get that much output.

Then there are light panels and COB lights that claim to emit over 100 or 200 mW/cm^2 at 10 cm away. Obviously this is a massive eye hazard if true, and if used inches away from the skin will reflect up to 95% of the light. That is why the best way to deliver light therapy is with skin contact to reduce reflection losses.

All of these layers of deceptions leads to not only a disappointing customer experience, but customers who actually rely on these devices for medical reasons won't get the results that they desire. This causes people to lose faith in red light therapy brands and effectiveness of this technology.

I wanted to see the highest-possible output possible from a flashlight-type photobiomodulation product. Which turned out to be a very easy to assemble a basic high-powered torch with an option to build it entirely with no soldering required!

Later, we will measure the optical output and power consumption of this light to see how powerful it really is.


LED Supply 5-Watt Module Kit:

- Cree 3-UP XP-E

- Deep Red 660nm

- Spot Optic

- Pre-Assembled

2.1mm Female Barrel Plug Adapter

12 Volt Adapter

(I use this one because I have tested it to be low EMF)


Small Philips Head Screwdriver

Step 1: Order the LED Module Kit and Tools

Ordering the LED Module Kit from LEDSupply is more than half the work!

LEDSupply has a 5-Watt kit and 10-Watt kit.

  • The 10-Watt kit they will supply you with a much larger and thicker aluminum enclosure, and a higher power constant-current driver for the LED.
  • The 5-Watt kit has a smaller aluminum enclosure and a lower powered driver for the LED.

Since I knew I would be getting a very high-powered light anyway, I did the 5-Watt Kit for this tutorial. You can see the comparison of sizes in the pictures. The larger 10-Watt aluminum enclosure has more thickness to absorb more heat from the LED and diffuse the heat it produces. So it might be better if you plan on continuously running it.

Select the 1-Up or the 3-Up 660nm Cree XP-E

  • The 3-Up LED has 3 individual LEDs on a single starboard!
  • The 1-Up LED only has 1 LED on the starboard.

We want POWER in this tutorial, so we are doing the 3-Up LED. For a lower power, safer, and still effective light then it is perfectly fine to do the 1-Up LED. In fact, I personally prefer the 1-Up led because I don't like too much heat on my skin.

Select the Spot Optic - gives you a narrow lens angle that focuses the light as tight as possible.

Select the pre-assembled or non-assembled.

  • Select pre-assembled if you don't want to do any soldering or assembly! It is only $10 to get this kit pre-assembled and soldered together.
  • Select non-assembled to practice your LED assembly and soldering skills. It could be useful skills for you to make more DIY Red Light Therapy in the future.

Step 2: Assemble and Attach

If you chose the non-assembled, then go ahead and put together the light!

If you chose assembled, then all you have to do is attach the 2.1mm barrel plug adapter. Just line up the red wire with the (+), and the black wire with the (-). Then tighten it down snug with the Philips head screwdriver.

That's it!

Step 3: Power It Up!

Now just plug in the power adapter and you have the most powerful red light therapy flashlight in the industry!

Remember to NOT aim this light at your eyes, ever. Consider wearing appropriate safety glasses when using this high powered light.

Step 4: Testing the Output.

This time I have to test with the LaserBee Hobbyist Laser Power meter, because it is too high to read with my SANWA laser power meter. You will know that a company is falsifying their intensity if they use a cheap solar power meter like Tenmars TM-206 or TES-1333.

There is some power output variation across the face of the optics, because of how the spot optics are outputting. But it is putting out impressively high numbers between 40 to 100 mW. Which when we divide by the surface area of the sensor of 0.09 cm^2, we get between 444 to 1,111mW/cm^2. This is incredibly high, which it seems the average output is around 666 mW/cm^2.

This type of output can feel HOT, especially when aiming at dark areas of the skin or areas that have dark hair on it. The hair heats up quickly and gives me a burning sensation within about 30 seconds.

Step 5: Testing the Power Consumption.

Another way to test the relative power of a red light therapy device is the watts consumed. This is the result of people knowing that companies lie about intensity, so measuring actual watts with a Kill-A-Watt or Multi-meter is a good way to compare the power between devices.

Amps: 0.46 Amps

Voltage: 12.23 Volts

Watts (Amps * Volts) = 5.6 W

That is 5.6 Watts being consumed by this light! Most individual LEDs on light panels are barely reaching 1 Watt, even though they claim to be 5 Watt LEDs. But there is a DC-DC driver inside that also consumes some wattage in this unit, and then the LEDs. So this is consuming likely 3 to 5 times more than the power consumption of individual LEDs in red light therapy panels.This tells us that relatively this is MUCH more powerful than most LEDs on the market even from the highest-class brands.

Step 6: Check the Penetration of the Light

One of the key features of Red and NIR light therapy is it's unique ability to penetrate the skin compared to other colors of the spectrum. Some people are skeptical about the penetration of red light into the body, lets clear that up with a quick check.

If you hold your pinkie finger over the white "flashlight" on your smartphone, then you will see the tip of the finger glow red. That is because all the other colors are blocked and only the red is penetrating through.

Well some companies will show you how their high-powered flashlight can penetrate through the palm to the other side of the knuckles. It does look impressive, but can be done with any generic red tactical flashlight in my experience.

Shining light through the knuckles is child's-play with this super high powered red light therapy flashlight. I can get fantastic penetration even through the "palm" of my foot! This is much thicker than the hand and even has tougher skin to get through!

This is the real deal for targeted penetrating treatments. I doubt any light panels that you have to stand 6 inches away get this kind of penetration because most of the light will reflect off of the skin.

Step 7: Disclaimer

This light can be very high powered. Extra caution should be exhibited for eye safety, as well as all the normal safety considerations of electrical safety and thermal safety with electronics projects.

All information in this article is intended for educational purposes only. It is not intended to treat, diagnose, or cure any ailment. Please consult with your doctor or trusted wellness practitioner before starting any new health activity including Red Light Therapy.