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Author Topic: 4 LED 'bars' with fade in, on for 20 secs, f/out?  (Read 366 times)
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Hi there Arduino Addicts!

Hardware & Programming/code question RE: LEDs

I've a sculpture that currently lights up using 4 pre-made LED boards. Each board has 16 LEDs with resistors inbuilt and runs off 12 VDC and approx 250-300 mA of current. I power all 4 boards using a regulated 12 VDC, 1.66 Amp power adapter/transformer.

My question is, using the Arduino Diecimila, how might the hardware and code be set up such that 2 of the 4 LED boards (red) do this cycle:
a). a 5 sec fade-in followed by,
b). remaining on for 20 sec,
c). fade-out in 5 sec,
d). remain off for 20 sec,
e). loop to a).

And then the other 2 boards (blue) do the same cycle but start with a 10 second delay after the red boards...

I'm thinking that maybe using PWM trigger from a pin and some arrangement of resistors and transistor(s) (perhaps a TIP 120 transistor to handle the high current aspect from the PSU?)

If anyone has any ideas/code/circuit schematics to help, that would be truely awesome  ;D - I have a basic knowledge of circuits, but not enough to figure this puppy out  smiley-wink

Many thanx!

Cheers,

Rich.
« Last Edit: November 15, 2007, 06:09:35 pm by Rich » Logged

Vita per Artem :: Life by Art

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Hi there Arduino Addicts!
I dont have a problem. I can stop any time I want.  ;D

PWM and high current transistors should work fine.
Cant help with transistor advice though. Never used high current stuff before.
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Classic !
Thanks Cheater - it's good to know that I might be on the right track with PWM & transistors (I only discovered what PWM was yesterday)..
Rich
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Vita per Artem :: Life by Art

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