artooman Posted March 31, 2004 Posted March 31, 2004 Here is the deal. I am going to build a 5ga refugium underneath my tank for three reasons: 1) increased water capacity 2) some degree of filtration (flame wars?) 3) could always use another project. previous threads have discussed similar setups, but I am mostly trying to build what DeskJockey created as shown here: http://www.nano-reef.com/forums/showthread...=&threadid=9838 Needless to say, his setup is sweet. There is one thing that concerns me, and that is the wiring of the float switch. The way he (and many others) have it setup is extremely dangerous because there is 120V AC power going through the switch! I don't want that anywhere near water in my house. Using a simple relay, you can run less current with a DC source through the float-switch, and the relay will control the pump safely away from the water. Doing this requires a relay and a transformer (120V AC-> 12V DC) for powering the float switch. A simple transformer would be to splice an everday 12V DC wall adapter from an old portable CD player or something like that. I would like to build something a bit more elegant which does not require too many plugs. Furthermore, I will use the transformer as a general pupose 12V power source that can be used to power LED moonlights, cooling fans, and any other 12V DC device I need in the system. I plan on housing all of this in a basic plastic wall outlet housing from menards. Hopefully, this will consolidate a bunch of things into a single housing and a single wall plug which can be safely kept away from the water. The interface will consist of a computer power cord to plug the unit into the wall, a 120V socket (or two) for plugging in the float-controlled pump, a miniplug socket for the float switch, and 3 or so miniplug sockets for plugging in system fans and LED moonlights that will be constantly powered with 12 V DC. I have attached the plan (or tried to, anyway). What do you guys think? Am I mad?
CU_Reefer Posted April 1, 2004 Posted April 1, 2004 I have been plaining almost the same thing. I, alas, am one of the many with the 120volt death trap float switch. I have been meaning to change it to a safer system with a relay but have not found the time. I was plaining the system that is shown here; Aquarium Electrical Systems so I don't have to use a dc converter. I'm not sure that it would be any cheaper though. If you are tight for space in the wall outlet housing you might want to try a pc power supply case. You can get a dead power supply at almost any pc repair place for free. It is a great source for wires and a 12 volt cooling fan. You might even see if they have any other dead parts that you can strip the molex connectors off of. It sure beats buying them. Keep us posted on how it turns out.
Chamkeeper Posted April 1, 2004 Posted April 1, 2004 A couple suggestions... Hook the relay coil and LED up in parallel, and add a test button if needed... Either use a solid state relay, or incorporate an MOV to ease the arcing on the relay contacts. Inductive loads (motors and the like) are notorious for frying relays.
artooman Posted April 1, 2004 Author Posted April 1, 2004 These are all great suggestions. I should definitely put the LED in parallel... not sure what I was thinking there because it will drop the voltage over the regulator coil. I will definitely consider adding some switches for various modes like "test", "always on", "always off", and "normal". What is the advantage of a solid state relay over a DPDT relay? Has anyone had problems with the pumping constantly turning on and off? I am worried about this. Given that water level and pump status are circularly related (like a chicken and egg), unless you match the input and output flow perfectly, the float switch will turn off and on. Perhaps the solid state relay will help with this? I was thinking that it might be better to have a "tolerance" where the water level can be between two points, but this would require two float switches and a circuit that could interpret the value of the switches. The idea here is that when both switches are "on" then the pump turns on, when both switches are "off" then the pump turn "off", and when one switch is "off" and the other "on", then the pump continues in the same state it was before (either off or on). Anyone have ideas or experiences on this? Perhaps there is a handy way to incorporate a time-delayed relay or the solid sate relay.
artooman Posted April 1, 2004 Author Posted April 1, 2004 Also, using an old power supply is a great idea. It is also a great source of giant capacitors and such. I will definitely keep everyone posted. I got a few people at work involved, and they also have some interesting suggestions for converting 120VAC -> 12VDC by using a transformer, a full bridge rectifier, and a nice sized capacitor. This shouldnt be a secret to Electrical guys out there, but I need brushing up on this stuff! I might just take a 12VDC power adapter apart and bite the bullet instead, but what fun would that be? Thanks!
CU_Reefer Posted April 2, 2004 Posted April 2, 2004 The float switch I purchased from http://www.floatswitches.net/ works great. They have a 1/16" difference between on and off. I have not had any problems with the switch. The pump only turns on ad off if I am messing around in the tank. It is a good idea to have on and off switch. I'm not sure if it would be worth it to add a test switch, you can always push down on the float to see if it is working. Your water level is also a good indicator. If the water level is constant you know it is working. It wouldn’t be a bad idea to have two float switches in series. If your float sticks you won't have to worry about dumping 5gal of top off water into your tank.
artooman Posted April 2, 2004 Author Posted April 2, 2004 I just ordered that switch! I am glad you recommend it. I am also very happy to hear you say that the switch does not toggle to quickly. I think I might go with a simple circuit afterall. Thanks!
Chamkeeper Posted April 2, 2004 Posted April 2, 2004 A solid State Relay has no moving mechanical parts. They use Triacs and some isolation electronics. The real advantage is the lack of make and break relay contacts that will not appreciate a motor load over time.
artooman Posted April 20, 2004 Author Posted April 20, 2004 I appreciate the curiosity! However, I am afraid that I have been temporarily stalled in my refugium plans. Well, there are few things that have stalled my plans. The first, is that my stand is exactly 1/4 inch too skinny to hold a standard 5 gallon under the display tank. I am currently looking for a comparable option that doesnt cost $60 (like these 5 gallon-ish stylish bowfront tanks), although I might just spend the damn money and get it over with. Second, I have a fish with parasites, so I have been spending my aquarium energy dealing with this. And third, I just havent had the time. I'll definitely give an update as things progress. I would like to continue the plan in the near future, and I have even picked out all the key components for the circuit. I may add some additional circuitry for a wavemaker option on my powerheads, and I am also considering the addition of some temperature probes and other warning mechanisms (power outage, etc). I was thinking that I could use my iPAQ handheld (which is currently being used as a 24-hour music server) as the monitor, and the circuit above could be modified to hook up to it. It would be cool to have my fish tank email and text message my cell phone whenever something stupid happens (like the lights being left on or the temperature going nutty). This, of course, is a big project, and I would like to merely think it out so that I can leave room for it in my design. Anyway, I'm babbling. Once I have finalized the refugium design with all the component part numbers, I'll post that.
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