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Discussion Starter #1 (Edited)
Ok, so I decided to do a bit of tinkering and hack an off-the-shelf dimmer into my Finnex planted+ fixture. It works great so far but I just completed the task. I'll post updates later to confirm it keeps working for me.

In part I was inspired by this post:
http://www.plantedtank.net/forums/showpost.php?p=6584722&postcount=16

And after some study and dissection/reassembly of the fixture, I came up with a plan.

Some warnings up front:

1) Do not attempt this unless you are good at soldering. In particular you should know a cold joint from a hot joint, and how to insulate connections properly with heat shrink, etc. While unlikely, if you do this horribly wrong the connections could short, heat up, and do bad things like catch fire. Don't burn your house down please.

2) I have professional experience in electronic circuits, soldering, etc. I'm not really qualified to judge how easy this is for an average hobbyist. For me, this was easy. I think an electronic hobbyist with reasonable soldering skills should also find this fairly easy. There's nothing terribly exotic going on here. Soldering the connectors is slightly tricky, as they tend to act as heatsinks, but if you crank the iron up too much they melt.

3) This WILL void your warranty. (btw Lowe, I consider my warranty void!)

4) This ONLY applies to Finnex lights using an external power brick that provides DC voltage under 24v and that draw less than 2 amps (I'd not trust cheap coax connectors above this without specs proving otherwise). In theory you can get decent quality coaxial power connectors that are rated to 5 amps, or even more, but I used cheap ones. The specific fixture I did was a Planted+ 30", which has a supply rated for 21w at 15v, which works out to 1.4 amps.

Some general notes on my choices:

I could have done a lot more elaborate design here, pairing a FET in with an arduino and done some nice programmable fade-in sunrise effects, etc. Some day I may expand this project and do something like that. However, I chose the simple approach here as my goal was really to get my light level down a bit. I also wanted to keep it cheap and simple as a proof-of-concept, I strongly believed it would work, but had no solid proof and a lot of mumblings on the forum of folks that were not sure it was possible.

So, what you need:

5.5mm x2.1mm male coaxial power connector, in-line type
5.5x2.1mm female coaxial power connector, bulkhead mount
4-amp 5-24v dimmer (I got mine at Amazon, but many similar products will work).



Opening up the Finnex (2 screws on the end), pulling the strain relief out with a pliers, and cutting the cord:


Hooking the power-brick end up to confirm which wire is positive vs negative. Note that on mine, one wire as a ribbed edge, the other is rounded. Make a note of which is which.



Soldering on the in-line connector (make sure to slide the jacket on first! Also, flux is your friend.) My dimmer wants the center-pin positive, I made sure to wire it that way (see above). Also, be sure to insulate these before putting the cover back on, otherwise it may press the wires together and short. (again, experienced solderers only please!)



After twisting the wires onto the bulkhead connector for the fixture, I did a test-run to make sure it works (I did not use the dimmer, just wanted to make sure the light would turn on):



The bulkhead connector, after soldering, insulating and screwing it into the hole that held the strain relief (near perfect fit!)



The fixture finished with the dimmer on high (pardon the camera lens flare):


and just barely on:
 

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Wow, that's so simple and awesome. Thanks for this walkthrough. I'm a fairly good solderer, so I may attempt this with mine.(same light)
 

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Discussion Starter #4 (Edited)
Don't give me too much credit yet, this hasn't been tested for more than a 10 minutes of on time yet..

We'll see how it does with tomorrow's light cycle... :)

edit: this was working fine this morning before I left for work, it was running for about and hour. We'll see how it is doing when I get home tonight.
 

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As a side note.. I pretty sure you could do the same w/ these program dimmers (using only one channel of course)

Good up to 5A.. ONLY catch I ever found is apparently some "buzz" or hum or make some such odd noise (may have to do w/ switching circuit harmonics or other voodoo) at odd voltages , like 15..

some are listed 12v some 12-24V..
 

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Discussion Starter #6 (Edited)
Yes, there are a lot of different ways you could go with this...

I really made a lot of my choices based entirely on cost and ease of hookup. Not being 100% sure this was going to work, I was willing to risk $10 in parts and an hour-or-so of my time. I wasn't willing to spend more on a nicer dimmer for what could turn out to be an experiment in failure.

I was also considering some 8amp 12-24v dimmers that use screw terminals, but I decided I wanted something that I could easily just bypass the dimmer if it wasn't working..

http://www.amazon.com/LEDJump-Dimming-Controller-Lights-Ribbon/dp/B00AM9H47Q/
 

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I just on a lark cut up one of my finnex lights and was able to hook it up to a current ramp timer without even taking it apart.. I just used one of those DC plug adapters with screw terminals (I have a bunch laying around already - and I did check the polarity of the light's wiring before hooking it up). Not quite as elegant solution as adding a jack to the housing, but it was quick and easy and I didn't have to source any parts to make it happen :)

I'm actually happy it was so simple... that means I may put some of my other finnex lights bakc into service rather than having them collect dust.
 

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Discussion Starter #8
Nice, glad to hear someone else has done similar tricks to this...

And you're right, I didn't really need to dismantle the fixture to do it, that was more a "touch of elegance" bit.

I also figured if the dimmer failed, I'd at least have given myself a removable/replaceable power cord. Since my fixture sits on a glass top, this will make it easier to remove the fixture so I can pull the top off for cleaning.
 

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Discussion Starter #9
Ok, so it has been running for several hours today. It is still working, and no signs of anything heating up at the connections or dimmer.

I think it actually works!
 

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mattinmd, your post inspired me to add a socket to my Finnex Planted+ 12 and add Current USA Single Ramp Timer. It worked out OK but I had little trouble fitting the socket - the one I have found has a bigger butt ;-). So I had to bend the aluminum case below the clear shield a little so the back of the socket would fit. It worked out OK and now the fish enjoy smooth sunrises and sunsets ;-)
 

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Discussion Starter #12
Yeah, I got a bit lucky on the fit... Going into it I suspected I might have to re-drill the cord mount, but as it turned out the fit was absolutely perfect.

For reference, these are the connectors I used:

http://www.amazon.com/gp/product/B00CQMGWIO/

Not that I think this particular ones are of any great quality, but they do have the advantage of being somewhat narrow in the back...
 

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Discussion Starter #13

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This is really interesting. What size light do you have? Just wondering if the parts used would be the same for a 36".
 

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Discussion Starter #15
I did it on a 30" planted+...

In general it should work for the 36", but I would suggest looking at the power supply, make sure it is 24v or less... it's probably a 15v like the 30" model.

And be careful with your insulating, there's been at least one report of a Finnex power brick catching fire (not related to this mod, but presumably due to a short). Make sure your mods don't short anything.
 

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Update:

This past weekend I swapped out the dial dimmer for an IR remote controlled one..

http://www.amazon.com/gp/product/B00KS20W7Q/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1

Prior to doing that I used my kill-a-watt meter to measure the power consumption, and I'd been running the dimmer at 90%.
Cool.. I've tried to get some that did the same to a Beamswork to "fess up".
http://www.plantedtank.net/forums/showthread.php?t=834218
Probably should have started it in the DIY area..

now all you have to do is add some color bars.. ;)

Have you spooked your fish w/ the "stoboflash feature".. LOL
 

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Discussion Starter #17
Cool.. I've tried to get some that did the same to a Beamswork to "fess up".
http://www.plantedtank.net/forums/showthread.php?t=834218
Yeah, I know and participated in your thread a bit.. I like the idea.


now all you have to do is add some color bars.. ;)
To be honest, my current plans are to get a second fixture that has color adjustment (probably a 24/7 when I can get my hands on one), and to control both dimmers with an ardiuno using IR. Hence, the switch to an IR controlled dimmer for the Planted+.

The main reason for a second fixture is to try and fix some of my light spread issues.. The 36bow gets pretty shadowy in some parts of the tank. Rather than run one fixture at 90%, I'll start off running 2 at about 50-40%.

Have you spooked your fish w/ the "stoboflash feature".. LOL
Lol, no... I haven't even tried it at all... maybe some evening I'll pull the fixture off the tank and try it out while I'm playing with the arduino control.
 

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Discussion Starter #18
So, I've done a bit of work starting to figure out the Supernight dimmer's IR protocol...

Using an IR receiver and some code from:
http://playground.arduino.cc/Code/InfraredReceivers

I went and captured and graphed the keys..

The protcol is interesting in that it starts with a 4.456ms high, followed by a very short .616ms low. It also appears to be encoded using pulses of variable high-time periods.. all the lows appear to be the same .616ms low. Highs are either .616 or something around 2.5x that long (1.6ms)...

This doesn't really fit with any protocols I've seen graphed out, but it isn't too far off from the sony protocol, other than the start being about twice as long..

Fun things to figure out....
 

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I just on a lark cut up one of my finnex lights and was able to hook it up to a current ramp timer without even taking it apart.. I just used one of those DC plug adapters with screw terminals (I have a bunch laying around already - and I did check the polarity of the light's wiring before hooking it up). Not quite as elegant solution as adding a jack to the housing, but it was quick and easy and I didn't have to source any parts to make it happen :)

I'm actually happy it was so simple... that means I may put some of my other finnex lights bakc into service rather than having them collect dust.
I am glad to here that the pairing of a finnex planted plus light and a current usa ramp timer worked for you. I am planning on doing the same thing.
 
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