neanderthalman Posted January 23, 2009 Share Posted January 23, 2009 A major update to V5, along with the PCB order can be found at post 63 Original post: ================================================================================ Allrighty, This has been a long time coming, and I'm proud to finally release the completed, fully functional DIY Automatic Water Changer. It's been through many revisions and testing of various designs, and finally have found what I believe to be an optimal solution. The design basis I set out for the project was to emulate a standard 10% water change, rather than the peristaltic "continuous change" systems. The reasons were based on efficiency, control, and space considerations. I have used three MJ1200's for each function of drain, fill, and ATO, but any other powerhead will work. I don't want to bash the continuous change folks, but my reasoning for this design is as follows. A continous change system needs to change out more water to remove the same amount of nitrates from the water column. 10% water changes do not introduce enough system instability to warrant the added operating cost in both water and salt. In addition, they require both a drain and supply reservoir to be connected to the tank at all times, consuming valuable real estate. Also, depending on the pump used, if the supply reservoir empties, the drain may continue to empty the tank without replenishment. Lastly, such a system cannot be accelerated to perform larger than normal water changes if and when necessary to avoid crashes and livestock losses. The other primary design considerations were inclusion of an ATO, cost, and ease of replication. I wanted this to be easily reproduced by others within the community. The design should also be robust enough to be adaptable to varying tank setups, though the demonstration will be on a tank with a sump. The current version, V4.2.1, uses only four DPDT 12V relays, and the associated diodes for kickback suppression. I have also included a V 4.2.1 PCB design that can be milled/etched, and is compatible with a standard 0.1" perforated prototyping board. EAGLE files are included below for those wishing to mill a board, rather than use a perforated board. Circuit: Board, top view - each square corresponds to a hole/pad on a standard 0.1" perforated board. Green octagons are wire connections, green ovals are the relay pins. Board, bottom view. Blue lines mark traces, for those unfamiliar with EAGLE schematics. Note this has been mirrored from the EAGLE file, so as to match exactly how it would "look" from the underside. EAGLE files: AWC.zip EAGLE can be downloaded as freeware from cadsoftusa.com The board is designed to use a relay such as the sanyou DSY2Y-S-212L or any similar DPDT relay with a DIP 2C pin layout. The circuit, however, will work with any DPDT relay - but you'll have to redesign this board yourself to accomodate it. I'll try to briefly explain the circuit. Three float switches are located in the tank. One marks the normal water level, another marks the lowest water level during a 10% change, and the third is an emergency backup, located above the normal water line. When the AWC is not active, the emergency float switch is closed, and there are no outputs. As evaporation occurs, the water level drops, the high level switch also closes. This activates the ATO pump to add water to the system from the ATO reservoir. This is not any different from a typical floatswitch ATO. If the high level floatswitch fails, the emergency float switch will be opened by the rising water. This disables the ATO pump and triggers the audible alarm. To perform a water change, the hose from the drain pump is fed into an empty bucket. A second bucket of freshly mixed saltwater and the refill pump, with a hose fed to the tank, completes the setup. All that remains is to hold the start button for a few seconds. This activates the drain pump and disables the ATO pump. After enough water is pumped out of the aquarium for the high level switch to close, the Master Control Relay will latch, and the system will complete the cycle automatically. This is a safety feature, so that the start function cannot be inadvertently triggered. When the bottom float switch closes, it will close and latch the Low Level Latch Relay. This disables the drain pump and activates the fill pump. As the water level rises, the high level switch will eventually open. This unlatches the MCR, which shuts down the fill pump and resets the system. The ATO is now re-enabled. If the high level float switch fails during a water change, the emergency float switch will also disable the system, as well as trigger the audible alarm. And there you have it. Clear as mud, I am sure. If you don't understand how relays operate, I'd recommend this as a primer. Here's a few pics of the demo prototype I tossed together. You will have to forgive the physical crudeness, as this was merely a prototype. I will be incorporating the circuit into the electrical panel of my stand. Please also note that the circuit board is a V4.2, while the board layout above is V4.2.1. Electrically, they are identical, however. Top: Bottom: For diode orientation - The stripe faces up: The enclosure is a trio of surface-mount electrical boxes bolted together. Two duplex receptacles are each split on the hot side. One receptacle is always on, and powers the 12V AC adapter. The remaining three are controlled by the respective 120V outputs from the AWC circuit, and serve as connections for the unmodified powerheads. The float switches were just twisted together with the correct few wires - again, I would expect better for something other than a temporary demonstration. There are separate toggle switches for 12V and 120V power to the circuit board, as well as three black momentary push buttons for manual bypass control of the powerheads. These are not shown on the circuit diagram, as they are not part of the board itself. They are entirely optional, and how to add them should be fairly obvious. The green momentary push button is the start button. Video of the unit in operation can be viewed here Enjoy! Link to comment
Scott Riemer Posted January 23, 2009 Share Posted January 23, 2009 I'm completely lost. Link to comment
Vancouver Reefer Posted January 23, 2009 Share Posted January 23, 2009 NICE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! I love your home made pcb with the solder as the tracks!!! Very innovative!!!! My project just seems to keep snowballing, but ill get some pics up next week, now that my parts have finally arrived. So whats your next project??????????? Link to comment
Kirin1 Posted January 23, 2009 Share Posted January 23, 2009 This is Art. Excellent project, even if it does zoom over some heads at 700mph. Link to comment
stoney waters Posted January 23, 2009 Share Posted January 23, 2009 ahleluia!! Thats freakin awsome. That will go good with my automatic saltwater maker and the robot I'm designing to empty my buckets. Great job. Link to comment
Otto Posted January 23, 2009 Share Posted January 23, 2009 I wanted this to be easily reproduced by others within the community. You sure about that? Looks cool though. Nice work. Link to comment
jejenkins Posted January 23, 2009 Share Posted January 23, 2009 You sure about that? Looks cool though. Nice work. I think he meant to say "others in the electrical engineering community" Way beyond me man. Link to comment
pendergraft Posted January 23, 2009 Share Posted January 23, 2009 I use the same Home Hardware buckets to change my water! (manually though). It is a nifty and smart idea but on a nano I only change like 3 gallons/week. I don't find it too bad to just mix, siphon old, add new. Takes about 15 minutes. But golf clap to you for making it cool. I am just impressed you can wire something like that, the drawings looked like a hamster maze, I was looking for the cheese at the end. Link to comment
mmelnick Posted January 23, 2009 Share Posted January 23, 2009 So... Ummm.... WHAT??? Link to comment
neanderthalman Posted January 24, 2009 Author Share Posted January 24, 2009 Thanks for the comments everyone! Seriously - if there are any specific questions, or any parts that are particularly confusing - just ask. I'll do my best to try to clarify things a bit. I do sincerely believe that this is reproducible by anyone who can DIY a floatswitch based ATO. You don't necessarily have to fully understand exactly how the circuit works to solder it together. It might something you've never done before, but soldering really is not a particularly difficult task. All you've needed is a reason to give it a try. Believe me, compared to the earlier versions - yes, this is "easily" reproducible. I'm sure nobody would want to buy (or build) a $200 PIC programmer, as well as learn how to use the software. To make it even easier, the EAGLE file can be submitted to a company like custompcb.com, and they'll ship you a nicely milled board for about $20 each. The minimum order at that particular site is two boards, but that's still only $40 - and you could arrange a group buy. Other sites might allow purchase of a single board.... Link to comment
travisurfer Posted January 25, 2009 Share Posted January 25, 2009 awesome stuff, so incredibly unnecessary, but awesome nonetheless Link to comment
aaren Posted January 25, 2009 Share Posted January 25, 2009 Thanks for sharing this, It's just what I was looking for. One question though, if you have submersible pump in your sump to pump out the water change water, won't you instantly create a syphon, and turning off that pump won't stop the water flow? ie, the sump will drain way past the FSLOW until the water level is below that pump and the syphon breaks. Link to comment
neanderthalman Posted January 25, 2009 Author Share Posted January 25, 2009 Thanks for sharing this, It's just what I was looking for. One question though, if you have submersible pump in your sump to pump out the water change water, won't you instantly create a syphon, and turning off that pump won't stop the water flow? ie, the sump will drain way past the FSLOW until the water level is below that pump and the syphon breaks. No. The other end of the hose is at a higher point than the low floatswitch. It is also higher than the final water level in the wastewater bucket. Thus, air is introduced and the siphon broken as soon as the pump turns off. It's definitely unnecessary, but so are many things like Ca reactors and ATOs that make our lives easier. Link to comment
Kraylen Posted January 25, 2009 Share Posted January 25, 2009 Amazing... I cant wait to see some videos or somethin of this. If all works you should start selling kits. Link to comment
travisurfer Posted January 25, 2009 Share Posted January 25, 2009 It's definitely unnecessary, but so are many things like Ca reactors and ATOs that make our lives easier. lol, true WILL IT BLEND? YES Link to comment
yellowslayer13 Posted January 25, 2009 Share Posted January 25, 2009 what? enrish prease. Link to comment
neanderthalman Posted January 25, 2009 Author Share Posted January 25, 2009 Amazing... I cant wait to see some videos or somethin of this. If all works you should start selling kits. Video of the unit in operation can be viewed here I've toyed with the idea of putting together kits....but I don't really want to incur the cost/hassle of doing so, as well as the hassle of settting up payment and shipping. I'd much rather share the knowledge with the community and let them do with it as they will. Link to comment
Kraylen Posted January 25, 2009 Share Posted January 25, 2009 94% of of the people in here have no clue whats going on here. Link to comment
HecticDialectics Posted January 25, 2009 Share Posted January 25, 2009 awesome stuff, so incredibly unnecessary, but awesome nonetheless that's what I was thinkin It's definitely awesome, but unless it mixes the salt water for you automatically, it's only saving all of like 45 seconds of work that it takes to siphon/pump water out of the sump and dump the fresh SW in... Still, easier's easier I reckon! And definitely still some cool factor to it Link to comment
Kraylen Posted January 25, 2009 Share Posted January 25, 2009 Its all about cool factor Link to comment
neanderthalman Posted January 25, 2009 Author Share Posted January 25, 2009 that's what I was thinkin It's definitely awesome, but unless it mixes the salt water for you automatically, it's only saving all of like 45 seconds of work that it takes to siphon/pump water out of the sump and dump the fresh SW in... Still, easier's easier I reckon! And definitely still some cool factor to it The next stage of the project will make it more useful, I assure you. I don't have the correct setup in this apartment, but once I buy a house, the plan is to replace the wastewater bucket with a sewer line, and the refill with a large capacity reservoir. 20g would be sufficient for this tank for a month's worth of water changes, and an even larger reservoir would be even better. Third, connect the ATO reservoir directly to the RO/DI unit, with a separate line for filling the SW reservoir. So, the system will always replenish it's evaporation without any user input. In addition, one can simply press a button on a weekly basis, or, we can set up a real-time clock circuit to do this for us. SW would need to be mixed on a monthly basis, or even less, depending. Suddenly more useful, right? Link to comment
Recommended Posts
Archived
This topic is now archived and is closed to further replies.