Well, the problem with a saltwater tank is that unless you are there every 12 hours to catch a mishap, you can only do the best you can and not worry about it. There are a bazillion failsafes I could apply, but, then it becomes too much of a job. The main goals are, no matter what happens (in the computers simplest form), aside from over heating, the tank can hold out a day. Vacations would be a little sketchy but is a given that the tank is up for grabs when that time comes.
Now, while I usually opt for NOT staring danger in the eyes when I have the power, I will be implementing a few fail safe modes. Until then, this is where I am at. I have ordered
1 ) cheesy 1 x 12 serial screen for $2 to let me know the arduino works (until I get the time to do the 3.2 touch)
2 ) 3.2 touch screen to use later down the road
3 ) off brand Uno to get tinkering for $11
4 ) 12 pack of relays
5 ) MB102 Breadboard Power Supply $3
6 ) DS3231 AT24C32 IIC High Precision RTC Module Clock $7.50
7 ) DS18B20 temp sensor
8 ) Breadboard and 40 male/female jumpers
9 ) Email notifications of failure, but, thats gonna be some interesting coding. I need to learn how to just turn on and off an electrical outlet first.
That should get me going for now, though I am sure I missed something. I plan to use the Uno for inserting code into the cheap chips, pulling them off the Uno board and then using them as standalone chips on other PCB’s. I can have every single device have its own controller and not take up any pins on the Uno and just have the Uno give me status and do routine checks etc. Maybe I could even write a ping code at the end of each unit to ping the Uno and if it does not get a signal, it alerts me to a problem?
Once the Uno is functioning properly in corporation with the other modules, I will probably try the Due board, or, if I run across a crazy deal on a Mega, I may grab that.
Well, more for the future, but, does that plan look okay so far?
The things I will tackle in the head as I start to practice coding/compiling will be
- brown outs
- Watchdog …something something, lol
- What relays do what when/with loss of power
- Extreme power supply filtering for a clean signal
Please let me know if I am missing anything or you want to expand on anything. Anything at all.
Editors note: For heaters, I think I will run 3 relays (they are cheap) in series on a N/O setup. One can stick all it wants. The chance of 3 sticking on at the same time??