AlanM

OK. I think I know how the little circuit board with the pot works. Or at least I think I do. It actually uses a change in current to dim the driver. I was measuring a 0-10V difference across the pinouts when dimming to 0 or to max power, but that was an Ohm's Law effect of what was happening with the current. Took me a while to figure out why they needed a little transistor on that board (the tiny square black thing in the middle with V+ on top of it). So it's not as easy as just supplying 0-10V on those two pins. I'd have to supply a fixed current along there, which isn't so easy. I'll pull the pot off the board, see what the rating is, and see if I can't drive it from a ditigal pot like I'd originally planned. DaveS, I could be wrong, but I think it's easy to do number 1 above. I snipped the two wires that control the dimming, the bottom two on the far right in my picture, and the light was happily on full bright and the fans were running. Replacing an a physical pot with a digital one won't necessarily work. Sometimes the digital pot gets pissed if the loads connected to the output resistance pins are referenced to a way different voltage than the signal and control inputs to the digital pot chip. That FET is probably a better way to do it than with a digital pot and arduino board etc. Could do it on one chip if you got one that would give you the right input and output ranges.

That channel still sort of works. And I've got one from the other channel to be more careful with. I'm pretty confident that I can figure it out, and once I figure it out I won't need this pot, so it should be fine.

haha, well I let the magic smoke out of the little circuit board pictured above doing some testing with a battery. Hmm. I should be more careful. Still playing with it.

I believe you'd do both. Silicone along the edge, smoosh the pieces together, and then put a cover bead in the corner after assembly to protect the edge silicone. At least that's how glass tanks are built. I'm not in any way a tank builder, so maybe Jeff the PimpedOut Naga can answer. 8)

Ok. Will try some stuff tomorrow. Will just twist in some wires for now and if it works will make a cleaner solution. That can be put back to factory config easier.

OK. So here is the pic of the potentiometer board: The pot is a 5-pin one which has an on off switch which are the two pins under the AMC and the 3 pins just over the surface mount resistors on the bottom vary the resistance. I'd planned to replace that pot with a digital one. It seems to be a 500k Ohm one. But then I saw the VDIM+ and the VDIM- which I've labeled Pin1 and Pin2. When the lights are on all the way dim I get 0.5V across those, when they're on all the way bright I get 9.8V across those. There are 4 wires coming out of this little board going into the driver which I think are vdim+, vdim-, fan, and ground. I think if I just put a 0-10V signal on the first two pins from the Apex or ReefKeeper I could dim these things and leave the pot alone. No arduino or digital pot needed. Marco, was there a place where people were trying to hack these things and ran into fan problems? I could see a problem if it was actually running some current through these vdim+ and vdim- pins, but at least on mine the fan speed doesn't seem to vary with the dimmer knob. I can at least put a little pot on a 9V battery to see if I can dim them that way so I don't risk drawing too much current from my Apex.

right. I have it open now, and I can see that the board the pot is connected to is a bit more complicated than just providing a dimming voltage.

If the ReefKeeper Lite Plus has analog outputs it seems like it should work just fine. This would just be replacing the knobs with a digital one that's addressable from an Arduino. I'm going to do a little bit of teardown of my D120 to make sure the forum guys talking about attempting this know what they're talking about. I think it would involve de-soldering the pots from the D120, but maybe I could just put the ditigal pot in parallel with the knob and add a little socket to connect a controller. Then you'd just turn on the knobs to minimum brightness and leave it there while the controller did the rest. If you wanted it all the way off you'd have to switch off the socket it was connected to.

Well, the 5206 has 6 pots, 12 D120's have a total of 24 pots, so you'd need 4 of em and 4 arduino boards. Wouldn't need that many channels on the apex though because those supply a voltage rather than a resistance. Actually, maybe I'll take apart my D120 and see what voltage is across that pot to see if a voltage would just work.

I'm working on a circuit to use an Arduino Uno and a digital potentiometer to allow an Apex to do dimming on a D120. Is this something folks would be interested in? Would cost about $40-50 for parts to control 6 channels of D120's, so 3 D120 units total. Edit: Would do this: http://arduino.cc/en/Tutorial/SPIDigitalPot with the chip shown in that article. Apparently the D120's use a 10k potentiometer to do the dimming, so the AD5206 has 6 channels of 10k resistors.

Beyond the concern for fish welfare, I couldn't take the choreographed ignorance of the main characters in that show. If those dummies on either Tanked or Fish Tank Kings actually ran a successful business without the TV show I'd be really surprised. I hope "dumb" is just a character they play on TV, not in real life. Also, I can't watch any of the current crop of over-produced and edited reality shows that only give you 5 minutes of content in 30 minutes and fill the rest with commercials and repetitions of zoom/pan shots or recaps of what you just saw before the commercial break.

I kind of can't wait to see this thing. With the discussion about the Tanked goombas doing it wrong, it will be fun to see it really done right.

Last July I was putting ice into my freshwater tank double-bagged in ziploc to try to keep the fish cool during the week of no power after the derecho. It was a pain. Maybe I should make some RO icecubes in case it happens again.

We have used Big Green movers twice in the past 6 years and they were great both times. No big tanks were moved, but they charge by the hour and showed up with three guys that RAN with our boxes the whole time so as not to waste time. They were really good. Also brought lots of boxes and paper delivered in advance and only charged us for the ones we used. And then gave credit for any used boxes we returned a week later in good shape so they didnt end up in the trash.

those things are so big they're going to compete with the fish for blackworms!

Tom, weren't you saying something about how you had to put extra extra screen over the outside part of the air intake to keep out the spiders and such?

Your tank is a beauty. It's amazing to see the difference from page 1 where you're asking about the goo growing on the sandbed to now.

We have buried power but somehow lose power frequently. No idea what that's about. I do enjoy the no power lines thing in our neighborhood, but don't seem to be getting the benefit of no outages.

Sounds like VA got the hammer and MD and DC were spared.

tornado supposedly confirmed in Rockville near Colesville. We had to go to our shelter-in-place at work until 1615.

Yep. We just got the black cloud and pouring from nothing to buckets instantly. Looks like it'll go by fast, though. Already lessening.

We just got a severe thunderstorm warning until 3:45 for Montgomery County. Supposed to roll in any minute with 60mph winds. I remain skeptical.

Sunny in Gaithersburg. Just saying. I do have 3 battery powered air pumps and a drawer of D batteries if someone around here ends up needing one, though.

I thought they were supposed to build 2 tanks in that mall.

I second what others have said. If you don't have definite desires for which tank you want and equipment you want, just hang around the forums here and subscribe to the WTB forum so you get emails when there are posts and probably within the month you'll see some really nice things you can put together into a system for way less than retail.