[cowanrg]

I made an LED ring light for my mill because lighting in my ship isn't so good and every time I bent down to look at a part on the mill, it would create a shadow and I couldn't see what I was doing. I used 12 3W LEDs, a power supply, PCB, and some aluminum. Here's a video of the process:



And here's an image gallery, that's largely screen caps from the video.

To give you an idea about the brightness, a 60W light bulb is around 800 lumens. This produces 3 times that on full, so it's like having 3 60W bulbs on the head. PLENTY of light.

[dracozny]

Nice job. I have contemplated this project for quite some time although I will probably opt for a more white color spectrum around 4500K.
Odd quirk about the video, I had to grab the link and watch it on youtube instead of embedded here on the forum. For some reason I can only see half the screen. Could just be my computer I did switch distros recently.

[cowanrg]

Yeah, it depends on if you want a yellowish or blueish tint. Really, the ~6k is pretty neutral. I use CFLs in the shop and they are pretty yellow, so the cooler LEDs are balanced pretty well. But ultimately, you can choose any color temp you want, the LED seller had just about every color temp available.

[dracozny]

I ran 6000k led lights on my mill for the last year, they are blue to me. According to any lighting chart you will ever find 4300K is as white as it can get before going blue (although I am still confused why they try calling 5000-6000k "daylight" it looks nothing like daylight). 4500K is just easier to find. interesting thing to note, many people think the higher kelvin color is brighter, but it actually outputs less lumens in comparison. I have dealt with lighting and the kelvin scale quite a bit over the last few years especially in the auto industry. A friend of mine is a retired lighting technician, he can pretty much talk your ear off about the subject. The main issue I have with the higher Kelvin is it bothers my eyes more than the 4300k and lower. Blue lighting is actually very fatiguing to the eye compared to yellow or red.

[cowanrg]

Strange that the bluer lights are actually used for applications where reading is involved....

But to each their own. I know from photography when I adjust my white balance, 4k is VERY yellow, and these lights don't screw up my white balance.

[CROSSHATCH]

Very nice LED ring.

Can you please provide details on which LED controller you used as well as the variable resistor? I don't have volume at the moment so I don't know if you mentioned it in the video.

I'd like to purchase the hardware less the LED's.


Thanks,

-Jason

[jalessi]

Robert,

Please post a link for the Aluminum PCB / Heatsink.

Jeff...

[dracozny]

Robert,

Please post a link for the Aluminum PCB / Heatsink.

Jeff...

I believe it is this one or similar

[jalessi]

I believe it is this one or similar

Dracozny,

Thanks you for taking the time to post the link however the part Robert used is much larger in diameter and has space for twelve led's versus nine.

Unfortunately the vendors store does not have the correct part either.

Jeff...

[dracozny]

Dracozny,

Thanks you for taking the time to post the link however the part Robert used is much larger in diameter and has space for twelve led's versus nine.

Unfortunately the vendors store does not have the correct part either.

Jeff...

Unfortunately that was the only ring I could find on ebay that remotely looked like the one Robert has. there are some others if you use "led PCB aluminum" you will come across a number of different shapes and sizes. only other option I can think of is aliexpress to search.

[jalessi]

Dracozny,

Hopefully Robert will chime in and provide more information.

Thanks again for the effort and taking the time to help.

Jeff...

[cowanrg]

Sorry for the delay, check the comments on the video. The store I got the PCB from is on chinese new year and has removed all their stock until they get back. This is their store on eBay.

[kawazuki]

For information - Natural Daylight on a clear day has a colour temp of 5600K and your eye's colour sensors are more acute at this and higher numbers. Obviously
once you go much above 6500 odd K its registering as blue and acuity starts tailing off. Working in sub 5000K light really screws with your eyesight!

[dracozny]

For information - Natural Daylight on a clear day has a colour temp of 5600K and your eye's colour sensors are more acute at this and higher numbers. Obviously
once you go much above 6500 odd K its registering as blue and acuity starts tailing off. Working in sub 5000K light really screws with your eyesight!

I can show you HID lights running at 4300k and you would swear it was white as white can be. If you actually find the blue tinted lights comfortable to your eyes more power to ya. people like me get headaches easily from such lighting, there are several studies about blue lighting and it's effects on the eye. here is some other reading material about the subject. Daniel Stern Lighting Consultancy and Supply

[minimum]

Hi,

Nice ring light. Couple of notes and thoughts (I hope you don't mind, maybe it helps someone who's about to attempt the same).

Color temperature: In general, below 3200K is warm white, over 5000K cold white and around 4000K is called either natural or pure white.
I would suggest 4000K as it's easier for eyes (less blue light) as has been already noted here.
Instead of thermal tape, thermal epoxy could also be used - in some cases it's easier to handle and is more reliable.
The case of the LED is not water- or moisture proof. Over time in high humidity environment, water seeps into the LED and damages it. Protective lacquers for electronics or waterproof case around helps.
Opal or "frosted" plexiglas helps to diffuse light if (many) sharp shadows are disturbing vision (lesser number of LED's, for example). Easier with reflective surfaces, like metal, too.

In current case, looking at the power supply parameters, I'm a bit confused - for this type of LED's, forward voltage drop is around ~3,4V (3,3-3,5V), so 12pcs in series should be about 40-41V. PSU is marked for 36V max, which would be around 3,0V for each LED. I guess the PSU works a bit outside its parameters, so it might misbehave if long wire between LED's and PSU is introduced (more voltage drop in wire). In full power (in theory about ~35W) and long working time, light may heat up considerably. High temperatures for LED's are not good. Rule of thumb is, when you're able to hold your hand on lamp's body, it's OK. If LED's start to emit much bluer light, it's indicating bad thermal connection between LED thermal pad and lamp body. In general, such LED's should be replaced as it's damaged and prone to fail quicker. LED's from decent manufacturers (Cree, Lumileds, Osram, etc) are more robust in many ways.


Regards,
Mait

PS: I make/manufacture LED lights for living and have done it for last 9 years.