Home made DIY LED baby light

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Re: Home made DIY LED baby light

[quote author=Jarred Land link=board=Links;num=1071261354;start=90#99 date=06/25/04 at 08:10:38]24leds wont light up a snowboarder in the sun..[/quote]

I've been playing around with my HID bike light which has a very bright spot. Might work fine for this application. It would also be easy to keep it aimed at the subject.
 
Re: Home made DIY LED baby light

"my HID bike light"

Yeah.. those things have about the same power as 1000 of these LED's.. if not more.
 
Re: Home made DIY LED baby light

For those of you who are thinking of building your own bank of LEDs, you may want to consider mounting them on a PCB.  For prototypes, I use www.expresspcb.com.  Their software is free, and if you use their standard board size (which you can cut down), you can get three PCBs for about $50.  This may sound like a lot, but consider how much time you'll spend hand-wiring everything ... and how much more stable a PCB will be when you're on a run-and-gun shoot.
 
Re: Home made DIY LED baby light

I'm sure the readers of this thread are already familar with "Lite Panels" on board LED lite. My question is how are they able to dim their lights from 100% to 0% without any color change. From what I understand LED's are like Halogen lights in that as you decrease voltage/dim light you also warm up the color temp. So how do they get around this?

I played with the Lite Panels at NAB and I can tell you that they ARE NOT dimming the lights by simply turning a few off at a time. Instead they are all dimming the same amount, together. Perhaps the dimmer is electronic and is turning the LED's on and off at a high frequency. Change the frequency of how often they turn on and off and perhaps you can change the apparent light output. Thats just my idea...Does anyone know how they actually do it?

Brett Erskine
www.CinematographerReels.com
 
Re: Home made DIY LED baby light

[quote author=Brett Erskine link=board=Links;num=1071261354;start=90#103 date=06/26/04 at 22:25:04]I'm sure the readers of this thread are already familar with "Lite Panels" on board LED lite. My question is how are they able to dim their lights from 100% to 0% without any color change. From what I understand LED's are like Halogen lights in that as you decrease voltage/dim light you also warm up the color temp. So how do they get around this?

I played with the Lite Panels at NAB and I can tell you that they ARE NOT dimming the lights by simply turning a few off at a time. Instead they are all dimming the same amount, together. Perhaps the dimmer is electronic and is turning the LED's on and off at a high frequency. Change the frequency of how often they turn on and off and perhaps you can change the apparent light output. Thats just my idea...Does anyone know how they actually do it?

Brett Erskine
www.CinematographerReels.com[/quote]

Interesting... I would imagine that pulse modulation would involve temperature fluctuations and resulting color fluctuation too... but I'm pretty clueless.

I'm building mine with multiple switches to turn some off...

-Barry
 
Re: Home made DIY LED baby light

Those HID lights sound very interesting. If they are many times brighter than LEDS I wonder why we havent seen them used in on camera lights.

Are they....? (1)full spectrum daylight balanced? (2)low heat? (3)dimmable? without color temp change?

What are the reasons why we shouldnt be making HID lights instead of LED lights for our cameras.
 
Re: Home made DIY LED baby light

I think those HID lights for bikes are rather new to that industry, I could be wrong though.
 
Re: Home made DIY LED baby light

Rather than describe what an HID looks like on a DVX, I found a shot where I used one with it a few months back. In my opinion the pattern is to tight, but the is planty of light output. And 4 hours of use from a 4x5x1.5 is not bad either.

Oh yea, the color temp does go up as the battery runs down, but it is not noticable until the last 15-30 mins. I believe that it is regulated.

dolby

HID.jpg
 
Re: Home made DIY LED baby light

yeah looks a tad blue. You could probally put some opal or put a fresnel lens on there to spread it out a bit. do you remember what power the light was?
 
Re: Home made DIY LED baby light

You're right Jarred, low wattage HID bulbs are are a fairly recent development. There are some different types of HIDs, but they're primarily metal halide or high pressure sodium or mercury. The bike lights are metal halide lights that work by discharging an arc through a mixture of xenon gas with some metal halides (i.e., sodium iodine and scandium iodine), and a little bit of mercury. The arc heats the metals and produces a glowing ball of vapor. The cool thing about metal halide lights is that they're much more efficient than incandescent or halogen lamps and they output light in the 5000-7000K range (close to daylight). Like fluorescents, they need a ballast to start them by producing a series of very short, very high voltage pulses to strike the arc.

If this sounds a bit familiar, it's because HMI's are metal halide bulbs. However, there's a growing number of low wattage bulbs that have some potential applications as battery-powered on-camera lights.
 
Re: Home made DIY LED baby light

Yeah they sound like they have even more potential that LEDS. Sounds like mini HMIs but cheaper. Are they dimmable? I've used 10K+ xenon movie lights and those were daylight balanced and bright as hell. The only thing about them was it takes about 30-60 seconds for them to come up to about full power. I really think we should look more into these. I've seen HID xenon bulbs and as I remember they are dirt cheap v.s. HMI bulbs which are real expensive. Imagine what you could do with the extra power of these lights. Some traditional on camera lights are up to about 100watts. You could get eight of these 12watt HID bulbs and get the output of 400watts, maybe more - and that not taking into acount that they are already daylight balanced and dont have the light loss problems of having a CTB gel. Perhaps it could still run off a second camera battery. It would sure be nice to have a on camera light thats strong enough to properly fill the face of someone that is back light outside. Anyone have more info on these bulbs? I read earlier that Lith-Ion batteries (camera batteries) dont handle high current that well. Anyone know how much they can handle? What other small/light weight battery technology can we use that can?

Well I think thats enough questions for now.

-Brett Erskine
 
Re: Home made DIY LED baby light


ok i don't know much about building electronic things but i have a friend who can build just about anything electronic...

can someone give me a summary of what it would take to build a light using these white led's that would be sufficent for inteviewing people at night in very low light?

i have situations where i want to interiew 1 or 2 people at fairly close range, say 6-8 feet and i don't want to drag around my lowel lights and light up the entire area.

often it is in an area where it would ruin the entire event/atmosphere to light up too large an area.

matthew
 
Re: Home made DIY LED baby light

bumping this back to the top...hoping for updated info from all you fabricators...
 
Re: Home made DIY LED baby light

well i just ordered a bag of 16,000 mcd white led's and a friend who is an electronics person is going to build me a light.

so other than having a dvx compatible battery charger to canibalize for the battery connector, and a dvx battery, what else do i need to have?

i mean a pc board and some wiring and a kit case of course, but anything else that would help me get started in the right direction?

matthew
 
Re: Home made DIY LED baby light

Well, I just built one using 30 "RL5-W10015 White LED"s (10,000 MCD, 15 degrees) from superbrightleds.com.

It's nice, but pretty blue - luckily I built it in a pattern that works well with gel sample books.  I also think 15 degree spread is a tad narrow... I'd suggest going wider if possible.  Of course, there's diffusors in them there gel sample books...

Anyway, I'm happy, but will probably build another (both because I was in a hurry and did an ugly soldering job, and to address the previous two issues).

For those interested in building, here's what I used:

1) 30 "RL5-W10015 White LED"s (10,000 MCD, 15 degrees) from superbrightleds.com
2) PC Board from radioshack, all independent pads
3) A Project box from radioshack that looked like it would hold he PC board (more on this later)
4) A Lenmar PP120 charger plate


I made 6 rows of 5 LEDs, as follows:

Code: 
123456789ABCDEFGHIJ
+-  +-  +-  +-  +-
 |   |   |   |   |   
 +-  +-  +-  +-  +-

+-  +-  +-  +-  +-             (each "+-" represents the 2 leads of an LED)
 |   |   |   |   |   
 +-  +-  +-  +-  +-

+-  +-  +-  +-  +-
 |   |   |   |   |   
 +-  +-  +-  +-  +-

where all pins in columns 1,5,9,D, and H are tied together, to positive
        all pins in columns 3,7,B,F, and J are tied together, to negative  
        proximate pairs of pins in columns 2,6,A,E, and I are tied together as indicated

I believe there are two empty board holes in each direction between LED leads.

This seemed the simplest way to accomplish this on the Radio Shack PC board. It can be extended by adding either rows (in pairs) or columns.

Note that Radio Shack sells PC boards and project enclosures right next to each other, and the PC boards seem to fit the enclosures. They don't. RS DOES sell an enclosure that comes with a PC board in the package... that's what I'll use next time..., to simplify assembly.  For this, I had to shave the PC board and use a glue gun...

-Barry
 
Re: Home made DIY LED baby light

ping
anything new on building LED light panels? Success stories?
 
Re: Home made DIY LED baby light

The good news: I put a prototype together a couple of weeks ago. I used a 3.6V (about 4.2V fully charged, actually) LiIon from a junked laptop battery, and an 'amazing' IC from Maxim, the MAX757 DC-DC converter. This IC allows me to control the output voltage, while the batteries are getting discharged. The IC should be good to drive 10-15 LEDs at 20mA each, so if you need more, it's possible to build 2-3 identical modules, to control 2-3 banks of LEDs. There are newer and better ICs available from Maxim, but those are surface-mount, and are too hard to solder (for my old shaking hands, anyway).

The bad news: I've tried 6000, 8000, and 12000mcd LEDs (from the same supplier, mind you), and they're all producing ghostly blue light! Certainly NOT the effect I was looking for...

Has anyone found inexpensive LEDs that are trully 'Warm white"?

http://www.maxim-ic.com/quick_view2.cfm/qv_pk/1167/ln/en
 
Re: Home made DIY LED baby light

"What do you personally feel is a fair price for this light?"

Hi everyone. I'm building a prototype on camera LED light system and want to put the specs out there and if the interest is high enough I'll sell them commercially shortly. First of all they look very much like these:

www.litepanels.com ($975 basic light with battery)

But mine are slightly brighter and come in both TRUE color daylight balance and tungsten balance color temps. They will also run off of the standard DVX100 camera battery (other models work with PD150, XL1-2 and VX2100 batteries). The battery mounts right to the back of the light itself. These lights create beautiful soft light just like you would expect out of a mini Chimera but do it much smaller, lighter and easier than the traditional halogen lighting currently available. Here are the specs of my LED camera light.

Size: 8.5"Wide X 2.5"Tall X 1.5"Long
LEDS: 200 count in either tungsten or daylight balance
Total Wattage Used: 12watts
Light Output: 350fc @ 1 ft
Light Beam Angle: 60 degrees
Run Time: Aprox. TBD (aprox. 1 hr on standard CGR-D16)
Operating Temp: 102 degrees physical bulb temp after 1 hr
Battery: Your extremely small and light weight camera battery
Cost: ???

A traditional halogen light with the same light output and soft quality of light would most like need to be:

1)50 to 100 watt light plus the cost of a mini Chimera soft box.
2)The operating temp would be more than several times hotter.
3)Battery life would be several times shorter.
4)You would likely be required to wear large 6-8lbs battery belts.
5)Requires its own charger system.
6)Often requires you to be teather to the battery belt so long shoots are difficult and steadicam isnt possible.

So what do you think? Give me some honest feed back so I can determine if its cost effective to produce these things for you guys. Sooo...

"What do you personally feel is a fair price for this light?"

Please everyone give a quick number.
 
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