10/01/03:
Well, The rock is coming along nicely...I am having some phosphate issues, but the remainder of the parameters in the tank are doing very well. I am keeping the calcium up, and the ammonia is still zero on day 4...I am hoping for a quick cycle with the refugium full of live sand, and the fact I didn't leave the rock out of water very long at all. Anyway, the temps outside are getting cooler, and the tmp in the tank is staying down...even so, the fans are causing me quite an evaporation problem. I am loosing over 4 gallons of water a day to evaporation. My sump can only go about 48 hours without needing a refill before the pump cavitates. I stopped working on the Controller project for a little while to make a solution to this evaporation issue.
I saw a small pump controller on one of the forums, it had a sensor for turning on the pump and a sensor for sensing the reservoir to keep the pump that is transferring water to the sump from running dry. Well, 90 bucks is WAY to much for that...heh, so here is another project for me. I decided that a simple little atmel microcontroller would let me make a cadillac of a top off system. I chose the Atmel 90s2313 because I had some extra ones, and you'll see in th end it fit absolutely perfectly with what the controller ended up doing. I decided that I might want to add another tank some day and that I didn't want to have to build another topoff controller, so my controller can control TWO seperate reservoirs and pumps. It also has the failsafes for the pumps in the reservoir to keep them from running dry.
I also figured that some people who might want to build this would not want to buy many of the floatswitches...they are advertised as about
25 bucks in most of the online aquarium dealers. So...I also added a mode switch so that you only need two float switches as a minimum. Two
floats will allow control of one topoff pump in a timed mode, and one failsafe float in the reservoir to keep that pump from running dry. The other mode
uses two floats in the sump (or the tank) and one in the reservoir for the failsafe. If both modules are used, then a total of 4 floats are needed for timed
mode and 6 for level mode. I will explain more about this in a bit. After I got this mostly designed I saw a post about someone selling the same
float switches advertised for $25 at dealers for $6 each....wow! The website selling these is: Float Switches
I have bought 4 switches, and am very pleased with the quality and the speed of ordering from that site.
I breadboarded the circuit, and wrote the microcontroller code...got all the bugs worked out on the breadboard...I used interrupts in the code for when the reservoir empties. This means that no matter what the microprocessor is doing, when the reservoir hits its low level marked by the failsafe float, the pump for that reservoir is stopped immediately....I guess that would be implied by the term "failsafe" huh? Here is a shot of the float switch..nothing special here...but very nice quality I think.
Next an image of the breadboarded circuit...just to show I practice what I preach....no matter how good you are with electronics (and I am not that good), you will ALWAYS be glad you breadboarded something....as an example, the relay driver IC I used is a darlington array, but being hasty, I failed to realize it was a sink and not a source...meaning I had it wired backwards...if I had rushed into a circuit board...well...I have done it before and that is why I always breadboard stuff now.
Next a closeup of the two seperate modules...meaning you can control two seperate reservoirs individually...I haven't seen that on a commercially available controller. I have seperate indicator LEDs for each pump...that is the red and green leds in the picture, in the parts list I simplified and just list two green...its your preference if you build it...I like seperate colors personally.
