Home made DIY LED baby light

  • Thread starter Thread starter Zoomforce
  • Start date Start date
Re: Home made DIY LED baby light

Hey.. to make a 12volt light you would just need to wire 4 LED's together in each group possibly requiring a small resistor.. so 3x however many rows you want.  3 in a chain may actually work as well without a resistor but not to sure..

The pattern is pretty center focused, so a diffuser would be great to use. My soldiering job kinda sucked since I wasnt really thinking too much about it so some of my LED's are a little crooked. I think if you put them in a circular pattern each row angled out a little you could make a pretty consistent flood.


You can see how strong the light is by looking at that setup photo I took.. the LED light is lighting the flowers about 3' away, and there are 2x100watt inc. as a hair light and front right... plus all the extra ambient around the room.
 
Re: Home made DIY LED baby light

Oh.. I didn't see the pics from page 2. Hmmm it looks like those LED banks are almost equal to a 20watt light? perhaps a llittle bit lower? can you confirm? Surely this would be a great replacement for my 50watt Bescor+Heavyass belt battery. But That 50 watter is BRIGHT!!! I wonder how many LEDs would I need to get somewhere close to that light level.
 
Re: Home made DIY LED baby light

It has the same output center spot to center spot as a 60watt light at about 5 feet but a much tighter pattern.. with a better aligned array you could do much better. To use the light I have as an on camera light in total darkness, you would need to have the talent pretty close (few feet).  Your bescor would probally have a much longer throw and a much wider beam. but....

the board I put the 24 LED's on has room for at least another 24, so you could effectively put 50 LED's on the same size light then your talking... from my battery tests last night you should get about 8 hours of constant use off one dvx battery for 50 led's.

I would put each LED equal to somewhere between 1-2watts of light.
 
Re: Home made DIY LED baby light

[quote author=Zoomforce link=board=Links;num=1071261354;start=50#61 date=12/14/03 at 19:15:41]Hey.. to make a 12volt light you would just need to wire 4 LED's together in each group possibly requiring a small resistor.. so 3x however many rows you want.  3 in a chain may actually work as well without a resistor but not to sure..[/quote]

We should stick to two LEDs per row and 7.2v. In my opinion you found the right arrangement.

The question, that many people not too familiar with electronics know, is this: when you make a series of parts, if you one piece fails the whole chain doesn't work.

As we don't know yet how long these LEDs will last, we have to consider that a LED may fail on us. If we use a 4-part row, then the chance of it failing would be greater then if the parts used were 2. It's the law of probabilities. More important than that: that 4-part row would be a larger % of our whole light than a 2-part row.

The combination you picked is a perfect starting point, both in the arrangement and the voltage used. 7.2 batteries are getting cheaper and cheaper, and they are quite reliable.

We just have to be careful on one thing: Li-Ion batteries do not like high currents, so there's a limit to how much we should demand from them. If we want to go higher in current we may have to use two batteries in parallel.

Six-volt gel batteries may be an option too, if we find a way to measure color temp when using them. This may not work, though, as these LEDs need from 3.2v to 3.6v to work. If underpowered they may warm the color temp but also lower the output.


Carlos
 
Re: Home made DIY LED baby light

Yes I agree, 2 are perfect.. the failure thing isnt that big of a deal on LED's because they should last 10,000 hours.. unless something goes wrong of course.

As for the color temp, when the battery finally did die I didnt notice any color shifts.. just a luminance shift.
 
Re: Home made DIY LED baby light

[quote author=Zoomforce link=board=Links;num=1071261354;start=50#65 date=12/15/03 at 07:10:30]Yes I agree, 2 are perfect.. the failure thing isnt that big of a deal on LED's because they should last 10,000 hours.. unless something goes wrong of course. [/quote]

LEDs are usually quite rugged, a lot more than a lamp. So they shouldn't be a problem. The only thing that can go wrong is one LED failing as time goes by. It would be wise to always carry a solder pen and some spares when on location.

Soldering basics and polarity are essential on LEDs. They are not like lamp bulbs. They are polzarized and are destroyed if inverted.

As I said on another Forum: if you want to go serious in video, it's a good idea to know something about electronics. Particularly on what you can do when something fails.

[quote author=Zoomforce link=board=Links;num=1071261354;start=50#65 date=12/15/03 at 07:10:30]
As for the color temp, when the battery finally did die I didnt notice any color shifts.. just a luminance shift. [/quote]

Can you be a bit more specific on that luminance shift? Did they die a sudden death or stayed low for some time?

Same care is necessary when using lights and batteries, because the latter shouldn't be totally exhausted. Electronic equipment turns off when it gets to a certain minimum voltage, but lights do not. As I am not too familiar with these LEDs, I am not too sure if they also cut off when they reach say 3v.


Carlos
 
Re: Home made DIY LED baby light

on the luminance shift I meant output dropped... it was gradual, meaning at the last hour it seemed to go from full to about 1/4 output.. that is when I stopped. When I get around to make V2.0, I will use my light meter to do some true measurements.

LED's do shut off when the voltage drops, I think your 3 volts is dead on. I believe red and yellow LED's can do the drop, but White and Blue LED's just turn off. Remember a white LED is just a movie trick.. its a blue LED with basically a CTO filter in front of the element.
 
Re: Home made DIY LED baby light

[quote author=Zoomforce link=board=Links;num=1071261354;start=25#46 date=12/14/03 at 08:54:11]ah ha... I knew somebody would make them.. they seem to good to not of been. I wonder how much.[/quote]

88 Euro, but the production type has only one LED. Don't know how much light that produce...

It would be nice to build a soft LED, like a big circle of LED's or a big size adjustable rectangle.
 
Re: Home made DIY LED baby light

just noodling this around a bit...would a small 'project box' from radio shack be a good initial housing for this? my mental hurdle is what to use for the batt mount that has the proper channels and electrical contacts for the panny batts.

the easy part is getting a hot shoe mount on the bottom.
 
Re: Home made DIY LED baby light

the front box is actually a Radio shack project box. The back where the battery attatches to has the proper channels and contacts.. Its taken right off a Panasonic Battery charger.
 
Re: Home made DIY LED baby light

Hello Everyone, This is my first post here and just registered so I can reply on this thread. I am a full time electronics technician and a part time wedding videographer. After seeing this thread, I got interested in building one. I saw the spec of this LED on the site given by Jared. Thanks Jared. According to the spec., 1 LED will draw a 20mA current to a 3.2 volts battery. Using Ohm's Law E=IxR, where E is the voltage, I is the current and R is the resistance. Since the voltage is given at 3.2 volts and current at 20mA, you can easily determine the resistance of the LED by using ohm's law formula: R=E/I, therefore the resistance of the LED is R=3.2V/.02A (1000mA=1A) = 160 ohms. Since we are using a 7.2 volts battery connecting to LED's, 2 LED's connected in series gives you a 320 ohms resistance. Now you can easily calculate the current drawn on a 7.2 volts battery using the ohm's law again. I=E/R, then 7.2v/320 = .0225A. We now conclude that a 7.2 volt source with 2 LED's connected in series will draw a current of 22.5mA. Then a 24 LED's will draw a current of I=12x22.5mA = 270mA. To determine the Power consumption, just simply multiply the current to the voltage which is P=0.27Ax7.2 = 1.944Watts. A 7.2V battery with a 1600mAH has a power of 11.5WH and will power the 24 LED's for about 6 hours, or simply 1600mAH/270mA = 5.92H.
Hope this clarifies all.

Jun
 
Re: Home made DIY LED baby light

Hey pro star.. that sounds pretty close.. I used one of my 3100mah cells and it last for about 16 hours.
 
Re: Home made DIY LED baby light

Yes Jarred, you will get 16 hours since one LED has a standard voltage of 3.2 volts and 7.2 volts battery with 2 LEDs in series has 3.6 volts each and the LED still illuminates really good even it reaches 6.4 volts drain on your battery.  I will be building one using my Ultralight-2 as a base.  I will be putting 32 LEDs in round and 4 LEDs connected in series with 8 groups.  My power supply is an Anton Bauer 14.4 volts.  This connection will draw a power of 2.6 Watts compared to my 20-Watt bulb with same or brighter illumination.  The UL-2 has very nice diffuser.

Jun
 
Re: Home made DIY LED baby light

Just an update, I have ordered an LED from this site:
http://www.superbrightleds.com/leds.htm
The part number is RL5-W10015, 10000 mcd with 3.4 volts standard @20mA and a maximum of 4.0 volts continous and 7.0 volts pulsating with 15 degrees angle of view. This gonna be a good match for the 7.2 volts with 2 LEDs in series.

Jun
 
Re: Home made DIY LED baby light

cool keep us posted how it turns out. those should put out a crap load of light.
 
Re: Home made DIY LED baby light

now THOSE are cool... especially the rings. And those floods, it says they can be used for Traffic lights and beacons?! Must be really strong...
 
You must log in or register to reply here.
Back
Top