Open source pH controller

[Mulletsoda]

Yeah... I've taken to purchasing Atmegas 10 at a time. ;-) Honestly, part of my thinking is as I'm not commercially creating this product, no where in my goals is that it be 'user-proof'. Things like all in one package... well... I've got electronics all over the place, wired to the ceilings, walls, computers without cases... A rats nest of wires makes me smile, not cringe. Not that I like messy things, but I don't mind a little bit of extra work or complication. (This is a working computer : http://img39.imageshack.us/img39/9562/img7203v.jpg ) Different goals have different methods, I like the idea of multiple options.

I was thinking of dedicating a board just to this sensor, feeding it unregulated voltage and having a 7806 regulator just for the heater (hell, they're only $ .50) as well as a 7805 for the op-amps that are going to have to be on there. That way it doesn't interfere with onboard temp measuring. I read in one forum the sensor requires something like a break in period where it's supposed to be heated for a full day. Have you heard such a thing??

My real goal is whole area automation. I want everything monitored and coordinated. This is going to require remote sensors anyway, so there's no way around that. I'd like to create my own board for the whole thing to keep it compact, but there are too many remote sensors for me to try to avoid wires. I have personal issues with wireless communication, so that's out for me as well.

Do you mind telling me if you used the Sensair NDIR sensor in your product? That's the one I've been eyeballing... looks perfect, far as I can tell.

 

[bipotato]

Mulletsoda, I'll be your first paying customer using it in a real room if you make something similar to a Sentinel CHHC-1 (shouldn't be hard), but with output that can be connected to a computer. Should at least offset the cost some.

 

[Mulletsoda]

When you say connected to a computer, what are you looking for? Probably not serial, that would be too easy. USB? Wireless? Cellular?

What do you want from that connection? Simple one way logging of data? The ability to upload new parameters and over ride remotely?

Hm... okay, here's the first 802.11 wireless solution that didn't get rejected outright that I've seen: http://www.sparkfun.com/commerce/product_info.php?products_id=9290 I'm big on security. Having unsecured communications is just bad form in my opinion, it's too loose a way to run something.

Here's another option, a little pricer : http://www.sparkfun.com/commerce/product_info.php?products_id=9607

I'm a bit away from this point... I'm afraid to come out with anything other than prototype parts because there are things I don't understand well enough to know nothing could go wrong (power supply decoupling, for instance) that I can't in good faith guarantee nothing will go wrong.

Yet. ;-) I'm actually gathering some $$ together at the moment to take a few online courses (this whole thing, actually :http://www.cie-wc.edu/Electronic-Engineering-Technology.asp) and I was thinking I would make the grow controller my main project. There are more than enough aspects to the grow controller for me to get to incorporate it into a good portion of the curriculum.

 

[BlackThumb]

Love the computer! I have one of those too. Different case but about the same form factor.

I understand your goal just throwing out heat issue if you do put it in a case.

Have not read anything about the MG811 since I threw my last one out the window a year ago.

SparkFun sells a break out board that should work with the MG811
http://www.sparkfun.com/commerce/product_info.php?products_id=8891

I am using the Senseair K30 on an I2C bus. Works great, good documentation and support.

A lot of people use the Telair sensors as well.

-BT

 

[Mulletsoda]

I wasn't recommending either of those products, nor SparkFun as a source. I use SparkFun's website all the time, but rarely end up ordering from them. Just throwing those out as possible ideas.

 

[bipotato]

Serial would be fine, anything better is a bonus. Yeah, for continual logging and whatnot. Added bonus if you have software on the PC end that can do other shit with it (send text messages via email gateway, etc).

 

[chef]

Congrats Blackthumb, that's nice!

 

[Mulletsoda]

One thing I was real curious about, is it worth it for me to purchase the stuff to make my own PCBs? That seems like it would be fun, but I don't have much spare time as it is to learn another something new.

$10 setup fee (shown as a handling charge) - $2.50 per square inch for 2 layer designs, $8.00/sq. in. for 4 layer designs.

So I figure my board will be ~ 3x4 = $40 for one. I am just thinking about the prototype board, not when I know I have a working board layout.

 

[BlackThumb]

Serial would be fine, anything better is a bonus. Yeah, for continual logging and whatnot. Added bonus if you have software on the PC end that can do other shit with it (send text messages via email gateway, etc).

You might want to have a look at mine.
It has "fuzzy logic" that really works.
USB for data logging, text messaging, etc. etc.

My web site needs a lot of work but it will give you the details.
http://www.thrivegadening.com

-BT

 

[bipotato]

Don't see it listed at Greenhouse Tech's website...

 

[BlackThumb]

One thing I was real curious about, is it worth it for me to purchase the stuff to make my own PCBs? That seems like it would be fun, but I don't have much spare time as it is to learn another something new.

So I figure my board will be ~ 3x4 = $40 for one. I am just thinking about the prototype board, not when I know I have a working board layout.

I roll my own single sided PCBs for prototype and you are right it is fun and rewarding. Investment cost is almost nothing.
I can share my method if you are interested.

Have a look at www.pcbfabexpress.com They are really good, fast and include solder mask top and bottom and silk screen on the top.

-BT

 

[BlackThumb]

Don't see it listed at Greenhouse Tech's website...

Right their site is not up to date.
They have had explosive growth in the past 6 months.
I'll have to get on them.

Shoot me a PM if interested.

-BT

 

[bipotato]

You don't have enough posts.

 

[BlackThumb]

You don't have enough posts.

Oh oops,

support at thrivegardening dot com will work.


Mulletsoda,

Sorry don't mean to hijack your thread.

-BT

 

[Mulletsoda]

Nah, I don't fret about things like that. No worries, bro.

I'd be interested in hearing your method, I've glanced through a few walkthroughs on the process, but I've only got a very rough grasp of the process. It would help you with that post count, too. ;-)

 

[bipotato]

You know what else would be awesome... is if you can somehow modify a digital bathroom scale so that it can output to USB or such. Basically wanna be able to set my tank on there and know when I'm near low.

Maybe there's a better way.

 

[chef]

Blackthumb, what is your software coded in?

I'm hellbent on using Flash/XML & found some dohickey that converts serial data to XML on the fly. So I'm good there I think?

I'm also intrigued by your single knob control on the faceplate?

Fun schtuff

 

[BlackThumb]

Nah, I don't fret about things like that. No worries, bro.

I'd be interested in hearing your method, I've glanced through a few walkthroughs on the process, but I've only got a very rough grasp of the process. It would help you with that post count, too. ;-)

Thanks man,

I'll put together a quick how-to with links on how I etch my boards and post here in an hour or so.

-BT

 

[BlackThumb]

Blackthumb, what is your software coded in?

I'm hellbent on using Flash/XML & found some dohickey that converts serial data to XML on the fly. So I'm good there I think?

I'm also intrigued by your single knob control on the faceplate?

Fun schtuff

Thanks for the complement chef.

The code for the micro is written in C.
The data logging is Python. I will be posting all the data logging code as open source to my site in the next couple of days.

The "button" is actually a joystick used in game controllers.
The joystick is used for menu navigation and changing values like CO2 level.

I am curious to know more about the "dohickey" you found if you don't mind.

Thanks

-BT

 

[Mulletsoda]

You know what else would be awesome... is if you can somehow modify a digital bathroom scale so that it can output to USB or such. Basically wanna be able to set my tank on there and know when I'm near low.

Maybe there's a better way.

You could do that many ways. What are you thinking of, weighing the CO2 tank? I was tossing around the idea of having an extra tank on hand, and when the controller sensed that it's activating the release didn't increase CO2 levels have it activate an alarm, or just switch to a second tank. That wouldn't give you much time to know when you were going to need to refill.