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Misplaced_Canuck 08-08-2011 02:12 PM

EBay fish tank controller build using Wal-mart parts
When I first saw/read about those eBay aquarium controllers, I thought they were great and I immediately bought 5. I built my first one out of a gray junction box (the sealed type) and it took me a good 2.5 hours to build one. I built a second one out of a 2-gang electric box, but it's a bit hokey (no fit and finish).

So yesterday I was at Wally World and decided to get a few parts to build my 3rd one. The first thing that came to mind was that those "square" electrical face plates look darn close to the size of the controller. May be it would work... So I got the parts to make it happen.

The build time was about 1h20m, including fetching tools, taking pictures, answering text's, answering calls, and flipping through TV channels. :D

Parts needed


1x 2-gang electric box
1x 10-ft 13A electrical cord (some folks have used spare computer power cords)
1x square electrical outlet
1x square 2-gang electric box face plate
1x pack of wire nuts (only 2 are needed).

Total cost was around $15, the electrical cord being the most expensive part ($8 I think - Darn copper prices!)

Tools required


Continuity tester (volt-meter) (optional, really)
Wire strippers
Razor blade cutter
Small flat screwdrivers (for the controller's posts)
Small Phillips screwdriver
Dremel tool with de-burring drum attachment (not pictured).

Fitting the controller to the faceplate

The face plate looks like it would hold a controller nicely...I verified to see that the controller would fit in the face plate.


And... It doesn't. It's actually a touch wider (may be 1/8"?) than the hole. Bummer. No despair, I took it outside (I didn't want plastic dust in the kitchen) and gently enlarged it with the Dremel tool. The de-burring drum really doesn't sand it down, it really melts the plastic from friction/heat. I did a little bit at a time, until the controller fit snugly (but not tightly).



After the work with the Dremel tool, I mounted the controller into the faceplate, and latched the holding clips snugly to lock the controller in place.

Fitting the controller into the 2-gang electrical box.


The gang box has a number of spots that can be made into openings for running wires. They also protrude INSIDE the box and this prevents the controller from fitting properly inside it. I punched out the top-right hole, and the 2 on one level lower (from the inside out).


Then I used the Dremel tool to grind away any protrusions from the holes that I opened up. The idea is to make the bottom as flat as possible where the controller will go. It really didn't take that much time, may be 5-10 minutes. Just go slow and remove a little bit at a time and do not "punch thru" the back of the box.

Misplaced_Canuck 08-08-2011 02:13 PM



I wrote a crude schematics on a post-it note (the next best thing would be a paper napkin of course). I wrote Black, Red and Green thinking it the cord had a red wire, but it was in fact white. (I'm no electrical engineer).

I counted the number of wires I would need, and figured out I needed a total of 8 wires. I figured that I'd need about 4" per wire for the connections.


I cut the end of the extension cord, leaving a few inches on the head in case I wanted to use it to build a 3-way dongle.

I checked that the green wire is the ground by checking the continuity of the ground leg on the cord to each of the wires. Green = ground, check.


I cut an extra 12" of the cord to get the 8 wires I need for the connection, and cut that piece into 4" pieces.


I removed the outside insulation on the last 4" of the main cord, and removed all of the outside insulation on the 3x 4" pieces.


I stripped and tightened the ends of each 4" wire to be used. I left about 1/4" for the ends that go into the controller, 1/2" for the ends that get wire-nut'ted, and about 3/4" for the ends that go on the outlet posts.


I ran the main cord through the bottom opening of the box (a new one I punched out), and made a simple loop to prevent the cord from being yanked out the back.

Misplaced_Canuck 08-08-2011 02:14 PM



In the above picture I screwed in the ground (green) wire of the main cord to the ground leg of the outlet. I've also attached one 4" wire to the "left" leg of the outlet.


I'm continuing the wiring job by attaching the 1/4" ends of the 4" wires to the controller. I tightened each one snugly into the controller but did not overtighten.


I intentionally broke the "right" side connector between the upper and lower portions of the outlet, so that one will operate for hot, and the other for cold.


That's the final wiring.

Putting it all together


I've wired the 2 wires for the sensor, and routed them through the same hole as the main cord. I also made a loop around the main cord to prevent it from being yanked out.

Here, I've screwed down the electrical outlet to the box, but not tight to leave a little bit of wiggle room.

I then gently tucked the wires behind the electrical outlet, and put the controller and faceplate on top of the box to try it out.

I adjusted the outlet, tightened it down, and put the faceplate on top of the box, and used 2 of the screws to hold down the face plate. Since the faceplate screws into the inserts (and NOT the box), there's nothing for the top screws to go into, so I just left them out. For looks, you could glue the remaining 2 screws into the outlet, but I'm all about functionality over looks.


That's the final product. Looks decent, works great.


The back of the box can be left as is, as there are no wires that show metal.


Or, you can put electrical tape to cover the holes.... Or whatever other material you so choose.


KuntyBrew 08-08-2011 02:28 PM

looks good im gonna have to try that but maybe an outdoor 2 gang box instead

Misplaced_Canuck 08-08-2011 03:19 PM

And the schematics...


The blue wires are the sensor wires.


Forddog 08-08-2011 05:04 PM

awsum cheap build im a contractor and i never thought about using 2 gang box i got a good 20 laying around. Totally stealing this idea..thanks


Misplaced_Canuck 08-08-2011 05:31 PM


Originally Posted by Forddog (Post 3152918)
awsum cheap build im a contractor and i never thought about using 2 gang box i got a good 20 laying around. Totally stealing this idea..thanks


Glad I could help!


shortyjacobs 08-08-2011 05:32 PM

That's nice. I used a open end junction box, cut a hole in the side, and screwed the "open" part into the wood countertop it's mounted under....doesn't look NEARLY as nice , or as neat, as yours. Well done.

sasky7777 08-08-2011 05:55 PM


Misplaced_Canuck 08-09-2011 08:13 PM

For good measure... a visual schematics:



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