IDEA: DIY Ringlight for video shoots.

[Jackster]

Hi all.

I am thinking about making a ring light to add to my camera when making videos at conventions.

WTF is a ring light?

Here are some photos,





The idea is that the light is evenly spread from the camera at what you are shooting.




So what I need is a load of LEDs and to be able to dim them. Also going to need to run off a 12v Li-Ion battery pack.


Just wondering what would be the best way to do this, the dimming part.
Think we are looking at about 200 LEDs.

Thanks guys!

[EEVblog]

Why not just buy a commercial one?
I know it's not as fun, but...

Take a look at the Elector ring light project I reflow soldered a while back. It's micro based, but you don't have to do that. Just look at datasheets for various LED driver chips and they'll have app circuits.

Dave.

[Jackster]

Why not just buy a commercial one?
I know it's not as fun, but...

Dave.

Love making things.

[smashedProton]

Just use a quad opamp to make a square wave, take the integral, compare it to a threshold (brightness setting), and current amplify it to drive the leds array.  Easy peasy

[c4757p]

So PWM? You can do that with a 555 as well - see Dave's video on that - and the circuit is easier to design, lay out, and build.

[bustedcap]

How would you get the colour balance correct? Some of the white LEDs give out a bluish tinge.

[KuchateK]

Some commercial units have mixed matrix of cool and warm white LEDs. They have independent control to set brightness for them separately. Better units have separate brightness and color knobs.