Long LED fade

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james13
 
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Joined: Tue Apr 05, 2011 3:24 am

Long LED fade

Post by james13 »

Hi...

I am new to the arduino and have been trying to pick up on the programming language and also modify code that is already written to make it conform to what i am looking to do.

What i am needing to do is turn the LED on at its dimmest for 5 hours then fade over the period of 3 hours, turn off for approx 6 hours and then a reverse fade over approx the same 3 hours then hold dim for an additional 5 hours then off for 2 hours.

Or something similar simulating moonlight to sunrise and then sunset back to moonlight.


any pointers or someone that has a similar program that i could tweak to fit what i am looking for would be great!

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adafruit_support_bill
 
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Re: Long LED fade

Post by adafruit_support_bill »

I have some code that does more-or-less the reverse of that for controlling aquarium lights. With minor tweaks it could do what you want. You would need a real-time clock module such as the ChronoDot or the DS1307.

james13
 
Posts: 2
Joined: Tue Apr 05, 2011 3:24 am

Re: Long LED fade

Post by james13 »

thats exactly what i would be doing with it....

and im guessing i could include an LCD read out (http://www.adafruit.com/index.php?main_ ... cts_id=181) to monitor time and date?

StacyD
 
Posts: 9
Joined: Tue Apr 05, 2011 1:06 pm

Re: Long LED fade

Post by StacyD »

Yep, a LCD would work fine! The character LCDs (16x2, 20x4, etc.) are the easiest to work with and since you really only need 6 pins for it that would give you plenty of space to expand on in the future (which you will!).

Also if you are doing aquarium lighting, may I suggest that you use a Mosfet driver controlled by one of the PWM pins (even motor driver chips will drive some of these lights pretty well as long as it takes DC). I did something similar for a friend with a turtle (using a pic as this was a few years back - yay high school!) and used an NPN simple driver to actuate a motor controlled potentiometer so he could use the lamp of his choice to run on US standard voltage. You could also use a SPI/i2C digitally controlled one that was AC tolerant for ease.

Good news is that Motor controlled potentiometers are very common on old audio junk and eBay. You could even use a logarithmic pot because of the way that the sun setting and rising emulates a logarithmic function.

If your box is going to be anywhere near the tank, use a plastic enclosure and seal it with silicone caulk (moist air and chemicals can wreck havoc on these boards).

Cheers!

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