Marketplace cheap LED ringlight as illuminator ?

rictsuk · Post by **rictsuk** » Mon Oct 13, 2014 12:39 pm

Dear colleagues,

LED ringlights commonly sold as automobile "Angel Eye Headlight" might be used as a light source for reflected (or epi-) and darkfield illumination of macro and micro specimens, both with a camera mount or a stereomicroscope.

Such LED product is available in a wide range of diameters (60-140mm), various colors, and comprises a high number (even >150) of LEDs mounted on a circular solid aluminum plate (Chip-On-Board = COB), light beam 180-degrees and power even >10W / ringlight. Some models are waterproof.

Input voltage is commonly 12/24Vdc or pre-regulated within a wide range, and the assembly already comes with a constant current driver. Current may also be varied with different dimmers (simple or more sofisticated, but still cheap).

A commercial website with technical info on those ringlights, dimmers and accessories:
https://www.superbrightleds.com/moreinf ... ifications

Examples of cheaper suppliers from China/Hong Kong:

http://www.ebay.com/itm/2x-80mm-93LED-C ... 43cbdecc36

http://www.aliexpress.com/item/2pcs-120 ... 50592.html

Does anyone have experience on using this kind of ring LED assembly ?

Thanks and regards,

Ricardo Y. Tsukamoto

Stevie · Post by **Stevie** » Tue Oct 14, 2014 11:00 am

I made one a few years back but haven't done much with it yet .
Here's a humble try out with a eos 5DII and a MP-E65 at 1x and 5x .
https://vimeo.com/24350985

rictsuk · Post by **rictsuk** » Tue Oct 14, 2014 11:49 am

Hi Stevie,

Many thanks for sharing your video on testing the Angel Eye headlight !

Subject illumination was quite intense in your video, even though you were using the 60 and 72 mm rings - which are the smallest ones available in power and COB LED number. Hence, any such COB LED size should provide enough light for macro specimens.

I am intrigued that large heat sinks are essential when using standard power LEDs, while heat dissipation is not mentioned for Angel Eye Lights of even 10W. Does it really operate without an extra heat sink ?

Cheers,
Ricardo

Stevie · Post by **Stevie** » Wed Oct 15, 2014 8:53 am

Mine are not cooled .
Also a correction , the video was shot with a Pentax macro and not the MP-E65 .

GemBro · Post by **GemBro** » Wed Oct 15, 2014 4:00 pm

Stevie ... they look like the bog standard (3528) Angel LEDs? ... if so the whole current consumption of the unit (in the above photo) would only be 225mA max ... very small and not requiring heat sinks at all ... you could actually get away with a 500mA driver (but always leave some head room) ...

Standard Angel LEDs cost £2 for a pair (China) ... COBs are a lot more expensive to buy due to their efficiency ... £14 for a pair ...

LED drivers are very easy to build and if they're 'pulse-width' driven they can retain their colour temp pretty well ... as opposed to just limiting (dimming) the current via a simple potentiometer ...

But a good call Stevie/Ricardo regarding the use of 'Angel Lights' for illumination ...

Gem