I've been thinking a bit the last few months of automating one of my aquariums. I know there are industral PLC automation controllers avalible in the $100 US range with 8 inputs and 6 outputs.
Dead reliable and very durable.
Rex Grig mentioned he uses Clippard products. I've seen Clippard stuff used in factories around here and asked until I found the local contact and sales agent, he dropped off a catalog the other day.
In it they have a little electric valve called the Mouse. I think someone here mentioned he had used one to just shut the gas on and off.
Life Cycles: Over 1 Billion
Response Time: 5-10 Milliseconds
One small moving part that moves 0.007"
So heres my idea..automate the lights with relays, the water changes with sprinkler valves and an RO system...fish food..plant nutrients..and so on...pretty much done allot already in one way or another. But,the one I'm thinking most about right now. The CO2. Using a PH probe and a PID loop in the controller one could have the mouse valve cycle fast enough to just give one or two bubbles at a time. At even 200 bubbles per minute the valve should last quite a while...about 10 years. A PID loop gives extreamly close control of a system process. Think of it as an extreamly smart CO2 gas PH controller that can adapt to water chemistry, varying pressures, flow rates with the ability to make manual changes on the fly without upsetting the system. It even adapts to PH sensor response.
I've even been toying with using Maxim one-wire system components I already have instead.
Then using a dedicated PC. I have an old one knocking around. It doesn't have to be fast. I'd run Linux and some dedicated software. Linux almost never crashes unlike Windows. You could even alter the water chemisty, lighting and water change frequency to mimic the seasons in a certain fishes natural habitat. It could be conected to the Internet and monitored away from home.. have a web cam connected...whatever ...it would be accessable, scalable and easy to modify. A bit of a big project..but just a bunch of random thoughts at the moment.
In the end it'll mean more time enjoying my aquariums and less time working on them.
So I'm looking for any and all feedback or sugestions, positive or negative. Who knows I just might be crazy enough, or just plain crazy.