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Topic: 4 LED 'bars' with fade in, on for 20 secs, f/out? (Read 853 times) previous topic - next topic


Nov 16, 2007, 12:06 am Last Edit: Nov 16, 2007, 12:09 am by Rich Reason: 1
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  ;)

Many thanx!




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.


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)..

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