Ph meter.

[thewndrer]

If anyone either has a schematic and/or code to make a Ph meter that could be connected to a computer for monitoring purposes, please let me know. I'd like to be able to monitor the Ph at least of aquariums. Better yet would be to be able to monitor the Ph, Alkalinity, and at least the Nitrogen and ammonia levels of multiple tanks. Right now though, I'll settle for a schematic or kit that would interface with a PC either ISA/EISA or PCI slot or even the serial port and allow me to monitor at least 10 tanks and log the results, say every hour. Thanks for any ideas.<p>[ April 27, 2003: Message edited by: thewndrer ]</p>

[Chris Foley]

There was a small topic a couple of months back on a similar issue:<p>pH meter<p>The first place you should look is Omega Engineering:<p>Omega Engineering<p>They have a number of pH meters available for very reasonable cost, with RS232 output. Their website also has a lot of technical information on the subject of pH measurement. Another, somewhat less accurate option would be to purchase the sensor itself (again, check out Omega) and construct an interface. However, there are a number of practical problems which are very difficult to subdue and keep any accuracy or precision, especially in non-lab environments (e.g. extremely high sensor output impedance, logarithmic sensor response, &c). ou can pick up a reasonably accurate pH meter for around $150 with serial output, and have it done with.
The concept of taking multiple water samples from different tanks was covered in a post this month<p>water sampler <p>Remember that you may have to rinse the sensor in buffer solution between samples. Good luck, and happy hunting.<p>[ April 27, 2003: Message edited by: Chris Foley ]</p>

[Dimbulb]

PH meter schematics:<p>The probe will most likely need to be purchased because it would be difficult to make.<p>http://www.cyberreefguru.com/electronics/phmeter1.gif<p>http://www.cyberreefguru.com/electronics/phmeter3.gif<p>http://www.lce.org/equipment/phmeter/phoper.html<p>http://www.e-insite.net/ednmag/contents ... 0813f1.pdf
<p>make your own:
<a href="http://people.msoe.edu/~barnicks/course ... eferen.htm" target="_blank">http://people.msoe.edu/~barnicks/course ... eferen.htm[/URL]</a><p>http://course1.winona.edu/jfranz/Lab/ise.htm<p>other sourses searching google under 'home made ...' ion selective electrodes<p>[ May 04, 2003: Message edited by: 1206DX ]</p>

[Chris Smith]

Ph meters don’t read nitrogen. The P is pour, or Air in french for Oxygen, and the H is hydrogen. Nitrogen being inert for the most part wont be read by a ph probe, who’s membrane has been calibrated for those two elements. Secondary reading might be possible, but not primary.

[thewndrer]

Thanks Chris and 1206DX, I'll be checking out those links. My best hope, Chris, is to have ALL the tanks connected to the PC via a card in a slot, then via programming either be able to switch between them or have them all displayed at once. Of course, logging would be in tabular form all at once to one file. From the quick looks I've had from the links you and 1206DX sent, I believe I may be able to concoct a useful monstrosity relatively easily. The hardest part will be to re-learn coding again and get that set up enough to get me by. <p>[ May 04, 2003: Message edited by: thewndrer<p>[ May 04, 2003: Message edited by: thewndrer ]</p>

[thewndrer]

[Chris Smith]

On a secondary note PH probes can measure unbalances caused from decay and such, and give a secondary reading of abnormality, as related to a good environment VS a bad one.

[Will]

I was going through some stuff yesterday and found an article about building a pH meter using an LM 351 and an LM353. I can't post it because it's printed matter. If you send me your E mail address I will send a copy of it to you via snail mail. The article also includes some useful information on calibration. It;s my belief that `pH' stands dor `Potential Hydrogen' , refers to the degree of dissociation of hydrogen/hydroxyl atoms and is the negative logarithm of the number of such dissociations in one gm (Or 1.0 gm.mole ?) of the substance.
Hope this helps

[Will]

Addendum - If you have access to EDN (Electronic Design News) (www.edn.com) the article appeared in the October 2002 edition on page 96