Another controller thread
 

Well the little guy gone and did it to me... Luckily standard heaters, set to 85f so his tweaks to the control panel trying to dial in 168f - just got the LCD backlight flashing an out of range condition - not an actual temperature...

Started eyeballing my options to re-jig the arduino based unit... only a few hundred bytes of code left to make the current controller talk different... And I've got to take away the local controls (no buttons/lcd to avoid little fishkeepers pressing buttons)

Not a fan of most of the commercial units (and again, most are arduino based, there's just not that much room for programs). They're also very specific... I'm wanting a bit more versatile (i have salt and fresh tanks to control)

So... Headed a different direction...

The basic plan:

Teensy 3.0 powered - https://solarbotics.com/product/52060/
Did I mention there's a way to program it from the arduino development environment? So existing code can pretty easily be ported? :)

Had a friend help me rejig the pH probe op-amp circuit (note this boards 3.3v IO rather than the arduino's 5v) Going to use OPA2349's - bit of a smaller chip to solder, but - they're cheap (2.69$ each), and they're meant for the more modern logic voltages. Benefit - it'll be solely driven off 3.3v and 5v - no extra wall warts/batteries just for the pH circuit. I'm targeting a full pH range - not the minimal range most are using; pH from 4-9, should leave us a pH resolution of .015 accuracy. Might bring an ADC in yet to improve that, but largely - I'm thinking that's as accurate as it needs to be.

Now the fun part - Control... Like I said - I need to take away the buttons/lcd from the kidlets reach. He can't unlock my phone, open the browser, then open the aquarium tab (yet anyway). This works better :)

How I'm doing that - is a fully different matter... I'm not going to deal with the fun of integrating a web server into the base controller. I want them separate anyway.

http://www.pjrc.com/teensy/sd_adaptor.html
http://dx.com/p/sd-to-microsd-transf...r-module-27001

http://hackaday.com/2013/08/12/hacki...wifi-sd-cards/

So, as far as my controller side - it's just saving data to a SD card. Easy to implement. But that SD card is in itself its very own webserver. These cards are <35$ - believe there's a fairly easy way to handle some minimal control back and forth across the SD interface (ie if there's something I really want to change - I can drop an updated config file from the webserver onto the cards fat32 volume, the teensy sees it - takes it and assimilates it from there).


Going to hammer out the op-amp circuit tonight, most parts should be rolling in over the next 2 weeks. Should still be able to have lcd and keypad control via i2c for those that want.

And yes, open source for the win :)