How To Build A Varying Power LED Ring Light

In today’s tutorials Matus Zošák explains how to build a varying power LED Ring light.

While the concept of using LED angel lights to make a ring flash is not new. This design adds a few important tweaks to this hack – power control, on/off switch and a clever way to mount the ring to a lens.

The Ring

The round base plate is made from a 3mm plastic sheet, similar to the one I used for my pinhole project. It is the material ad agencies use to make plastic signs. It is perfect for DIY projects – it is cheap, durable and easy to work with.

On this base plate I glued 3 LED angel eyes rings, with different diameters: 120mm, 140mm and 160mm for a total of 132 LEDs. (If you are seeking a cheaper source, try eBay)

I made a small case from the same material and extended cables from the three rings all the way to the case. The hack here was to use SATA cables. I soldered a female sate on the back of the plate. The cables hold 6 pins and can carry small amount of current.

To diffuse the lights coming from the LEDs, I used a lid from a gammy bears package. It was sanded with a fine paper and partially painted black.

My solution for placing the ring on the lens may not be optimal price wise, but I have a broken Cokin P holder so I glued it on the back side on the ring, making it a snap to mount it on any lens holding a Cokin adapter. Another solution may be using a broken (or cheap UV) filter just for the threading.

Power & Control

The control box is a small electric project box. There are many of those on eBay. The brightness control system is based on 3 linear potentiometers so there is no complex electronics, everything is wired in serial.

Next to the potenciometers, there are 3 miniature on/off switches.

On the side there are 3 female 3.5mm mono sockets for connecting the power supply.

On front side is another SATA connector, this time a male connector. This entire “control box” is mounted on camera by using a hot shoe cover, which is glued on the bottom of the case.

With the Cokin adapter, mounting of the ring is done by pushing the ring onto the lens. and connecting the SATA cable.

Power Box

To supply power for the rings, I used three modified AA battery holders with an on/off switch.

I fitted each one with a 3.5 mm jack to connect with control box

One LED ring is powered by 12V, so therefore 3 holders and 12AA batteries overall. They are connected to control box by using 3 short coiled cables, which each has 2 3.5mm jack connectors on the sides

Building of this was quite fun, I only cut my finger once, so kids, wear protection ;)

Here are two shots taken with and without the ring: