LED moonlights that dim to the 29.5 day lunar cycle

wetWolger

wetWolger

New member
I posted a topic in the general discussion area but it soon became apprent that I need the expertise of the DIY forum. If you want to look at the original thread here it is:
http://www.reefcentral.com/forums/showthread.php?s=&threadid=753363

Here is where I am at and what I want to do. I want to DIY some LED lights that dim based on the 29.5 day lunar cycle. The easiest/cheapest way I can think of doing this is by using a Microcrontroller. I think a AVM or PIC controller is the way to go, inparticular I think the PIC would be ideal. A couple links I got for getting the controller are these:
http://cgi.ebay.com/ATMEL-ATMEGA103...ryZ50915QQssPageNameZWD1VQQrdZ1QQcmdZViewItem
http://www.microchip.com/ParamChartSearch/chart.aspx?branchID=1031&mid=10&lang=en&pageId=74

I have very little experince working with these, but there seems to be quite a bit of documentation for compiling. So any help on telling me what would unit best suite my needs would be excellent. Also I am not sure what else I would need to do this. If you look at my first post you see that I thought LM555 to dim the LED's since obviously you can't just change the power to them. But with more thought and research I think that if I get the right microcontroller it will be up to the task.

So I am mostly looking for input as to what microcontroller I should get, and what other equitment I will need. If anyone has done this PLEASE post, I would much rather learn from you than reinvent the wheel. As for me when/if I get this project done I will post a detailed how to thread to share the wealth :-)
 
Have you done embedded programming before?
If your asking for what chip you should use I think you may be a little over your head, please take no offence.

I would suggest you buy one of the many little pre made project kits or an eval board. That way all the supporting parts are done for you. Then you just need to do the drive and software.

How where you planing on driving the LED's? Analog? PWM?
 
post on one and get directed to another and then forwarded to another.....lol.....thanks for the link, I will post the same thing here in a sec
 
I posted it on the R3CA forum here:
http://reefcentral.com/forums/showthread.php?s=&threadid=753755

fppf: I did not take any offence, this is new terrority for me. I have never done any embedded programming before, but I have done lots of other programing. I am a computer science major and love to get my nails dirty in new tech stuff. I am mostly using this project as a way to learn. It may be too hard, I don't know, but I wont know till I figure out exactly what it will take to do.

Thank you all for looking :-)
 
Haven't done any embedded programming...but I've dabbled with a PLC before and think you could probably do it with one of them...but the cheapest PLC will run you around $100 (ezautomation.net for one).
 
$100 or u can take the easy way and just buy it from fishinnovation or was it fishbowl? i forgot where I saw it..
 
You can buy the LunarTracker from Here for $49.95 without the lights. I looked into making one but I do not think that you could do it for this price.
 
I don't see where they get off charging $50 for that. I mean come on there most likely is not even a micro inside it, just a 29.5 day sin wave generator circuit.
 
I was kind of thinking that maybe they varied the power output of the LED by means of pulse width modulation, although maybe they just change the voltage to a bare minimun.

I don't know if I could put it all together for $50 is kind of my problem.
 
Since no one was posting in the R3CA forum I figured I would post an update here.....A coworker at work loaned me a stamp to test out. So I got it today and have been messing around with it. I was able to get it so the LED's brigten and dim based on 59 diffrent intensitys (so it would adjust twice in a 24hour period) All that seems to work down to a tee. Right now I have it doing the whole cycle in under 30 seconds for testing. But I have hit a snag, one I do not think I can get beyond. Inorder for the LED to dim it has to be on for .0001 seconds and off for .00035 seconds....And in the brightest setting it is just on for .0001 seconds and off for 0 seconds....Well each time it makes a loop through to keep the LED's flashing it takes a diffrent amount of time based on how bright the led is. So the dim days would last forever and the full moon days would go by very quickly. I can not find a way to get around this without some sorta outside clock to tell it how long it has been running. So it pretty much died there. If anyone wants to see my very VERY ruff code here it is:
http://pastebin.com/514051

this post is more of a documentation of how it all ended, than looking for help. I personaly can not see anyway to get around this with the limitations of the hardware. The only thoughts I had are maybe a PIC would be able to do this (i have no idea what they are capable of).....or maybe I would be able to do this with an LM555.....I am just not sure....so any input would be nice, but I don't expect any :-)
 
Hey jent46bow, I have tried the same thing with the stamp. I had mine running for a few days using a simple light timer to switch a 5vdc input to signal the stamp to change the LED's brightness. I have one of these ordered Pocket Watch to give a try. at $30 plus the stamp it makes the lunar tracker for $50 seem more attractive.
 
I did some seaching and came across this discussion and was going to do some more reading and see if I could program a PIC to do what I wanded.

Tou are going to have a loop counter that will have to be changed depending on the brightness of the LED so on the brighter days the counter will have to be longer than on the dimmer days.
 
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