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Topic: Help to build a LED PAD for films makers ; I will make a video tutorial ! (Read 1 time) previous topic - next topic

lebigmac

Hello,
Like many Film Makers, the problem number 1 is the Light.
If you have (a lot of) money, you can buy that stuff ;
http://www.favnet.fr/IMG/jpg/Lite_Panels_1x1.jpg
http://www.favnet.fr/spip.php?article10158
But It Worths... 3 000$.

Since i'm working on Arduino, I think there may be a way to build that by myself.
If you can help me building It, I will make a video tutorial to help all the other Films Makers !

I'm not very good at electronic, So I devided into 2 parts ;

1) Power :
IHow many LED can I control with An arduino ? (100 ? 300 ? 500?)
How Can I use a "cine-like" battery on the Arduino ?

2)Dimmer and Color
As you see on the Back, there are two Knobs
One to dim the LED.
One to change the color of the LED (From 3200k(blue) to 5600k(orange). We Use It in Video, But is it meaningful to you?).
How Can I make It ?

I hope you can help me,
Or link me pre-existing tutorials ?
thank you very Much !



Chagrin

To control this many LEDs efficiently you need a more complex control. The datasheet for the Allegro A8512 shows how this could be done. It's not a novice project, but guessing from my armchair position I think you could manage this functionality in an amateurish version for under $200 in parts.

To answer your question as to how they control the color between 3200K and 5600K, they do this by having two major groups of LEDs. One group naturally emits 3200K and the other 5600K, and to get the range between is just a matter of blending them. Take a look at the LED selection on a site like Newark, Mouser, or Digikey and you'll find just about any shape/size/color/brightness of LED you can imagine.

lebigmac

So The Arduino can not manage that many LEDS ?

I Want to make a big One like this, and a smaller one.
Will the Arduino be OK for a Small pad with a dimmer ?

I'm trying to translate the "datasheet" (I'm French, with no background in electronic..)

OK for the Color. That's what I was thinking, There are 2kinds of LEDS.
I dims the blue and lights the Orange to get orange.

robtillaart

Quote
IHow many LED can I control with An arduino ? (100 ? 300 ? 500?)


It all depends on the addressing scheme you use, (assuming you use an UNO, and single color LEDS, full color divide by 3 ;)

A directly controlled LED's  => ~the number of pins (about 20)
B matrix config => 9x9 => 81
C matrix config with two - http://docs.macetech.com/doku.php/centipede_shield ==> 64 x 64 = 4096  [I2C based]

D:  use (B) and keep the I2C pins free you can address 127 slave I2C arduino's with 81 leds each => 127 x 81 > 10.000

So I think almost any amount of LEDS can be handled. The real problem will be the interface how to make it clear for the user how to control all those individual LEDS. The user probably wants to group them, that means quite some RAM for administration.

Furthermore to send 10K LEDS an on/off signal takes time so using an optimized protocol makes sense.

Finally it will be difficult for an Arduino to hold the state of all LEDS in memory in the controll unit.

Conclusio: consider using a PC (tablet) as master control and arduino's as slaves






Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
(Please do not PM for private consultancy)

lebigmac

Ok,

The C Solutions seems perfect To me ;
I need between 200 and 1 000 Leds (maximum) on the Pad.

So, as I don't use the "D" Solution,
Do you think I can still use an Arduino, with 2knobs (Dim and Color) ?

Thanks

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