Talk:PPM Meter Alt

ykcnvcmfb, http://medicaltransactions.net/justhost-coupon-codes/ justhost, NaeVtPL.

ilezncmfb, http://freelifesinsurancequotes.com/get-a-free-life-insurance-quote life insurance quotes, yQVCwMZ.

njodzcmfb, http://blackjackonlinearticles.com/ Online sexy blackjack 2, rLYjjQA, http://ultraenhancebreatenhancements4u.net/ breast enhancement cream, xvVXEWT, http://gethangover.net/ how to cure hangover, kWxpiss, http://slotsabc.com/ Real online casino slots gambling with real cash prizes, RgSbPNr, http://poker2k.net/ Play free poker, pXKyeHf, http://abouthomeinsurancequotes.net/ Nj state home owners insurance quotes, XIZMwEX.

qphnacmfb, http://webhostingreview.org/lunarpages/ lunarpages review, vRBTFXO, http://thesymposiumgroup.com/coolhandle-coupon-codes/ coolhandle, zWZWRhu, http://1psoriasis.net/ Treating psoriasis with essential oils, LiNVRmB, http://getahosting.com/windows-hosting/ windows web hosting, ZYxxSaN, http://getproflightsimulator.org/ ProFlightSimulator, GeUOORu, http://commissioncrusher4u.net/ Commission Crusher, kKLQsnN, http://quitssmokingnow.com/ stop smoking, sulzSvr, http://coilcorner.com/ jenny craig reviews, PVkUzQQ.

bekutcmfb, http://4300northmarinedrive.com/ women's diet products, FnVaVlO.

mlhyacmfb, http://www.seattlediscount.com/ fishfinders, NZIRLqF.

gowrtcmfb, http://www.clowncarblog.com/ Ambien cr generic, neqVgZK.

Stainless steel probe

Hi there,

My name is Daniel and i'm a electronics/microcontrollers entusiast. I've found you project very interesting. I've also come across a web site mentioning that commercial ppm meters use staineless steel probes, and i'm in the process of experimenting with a homemade one.

I'm building a probe thats very similar at least it looks similar to the ones in those cheap comercial ppm meters. A friend of mine will machine a piece of PVC to shape the probe, and i'm thinking of using staineless steel screws with the screw head removed (a 35mm M4 CHC cutted to make it smaller). They have a threaded part and a non threaded part and it will be the non threaded part that will come in contact with the solution to me mesured.

I was wondering if anyone has tried this because stainless steel screws are cheap and easy to find. It is also easy to make the connections and it is very robust.

I'll post here what results i'll find with this kind of probe. It will take me a couple of weeks because i have other projects going on.

Keep up the good work :)

• Thanks! will be interesting to see how this works out. ^^ eris

Split Rail

I was researching for a way to measure water conductivity and I stumble upon your project. I've decided to give it a try but I have no experience with op amps.

One of questions I have is whether its possible to power the circuit with a rail splitter such as this:

Lastly, is there a way to check the oscillation without using an oscilloscope? Maybe a pair of leds?

Thanks!

• to check without a scope, a volt-meter set to read AC may work.. AC mode should reject the DC components and just display the AC (or osciallation) voltage. In this case adjust until the voltage jumps up from @ or near 0.

• The split-rail would work, just be sure that whatever your connecting to read it (such as A/D converter or meter) uses the same ground. I have been considering rebuilding mine using a charge-pump circuit. Another great reference and source of pre-made components is Maxim

• hope thats helps ^^

Thanks for the info on the charge pumps, I've gone ahead and changed my design to use a charge pump.

I'll be using a single 500mA 5-volt regulator to power the op-amps, the charge pump, and the micro-controller. Any advice on using single supply?

Lastly, I've added a capacitor in series with each leg of the probe to block dc currents.

Thanks for your help and keep up the great work!

---

Change output voltage range??

Hi,

Thanks for all the great info and the design.

I'm about to try and solder the PPM meter. Just bought me all the components I would need but before I start I had a small question.

My A/D converter has a range of 0-10v. Is there a way to make this circuit output in that range for EC values of 0-3 mS?

Like by changings the value of some resistors?

Thanks!!!!!!! :)

Eagle source files

Would you consider making the eagle source files available? It'd make it easier to mill/etch the circuit board, get a list of parts, etc.

thanks!

A few questions...

First off, thank you for posting this interesting project. I am trying to product a prototype of it for myselft, however I have run into a few questions along the way.

1) I noticed that on the Eagle files, C1 and C2 are 0.15uF while on the original document they are labeled as .015uF. Were these values changed for any reason, or is there a preferred value which you would recommend?

2) There are four diodes in the AC to DC conversion section, and they seem to be acting as a rectifier, however I was unsure of their values. It was mentioned that D1 and D2 are 5.1v zenner diodes, but I didn’t know what proper values to use for D3-D6, could you suggest any?

3) C3 is a .22uF capacitor and in the pictures appears to be a electrolytic capacitor (or perhaps a non-polar cap?), but if it was polarized, I was unsure of where to place the anode. Or, I thought maybe I could trace the signal to determine the polarity with respect to pins 13/14 on the IC?

4) Lastly, does this project require 12v and -12v? Or, have you seen any success with running at +/-5v?

Again, many thanks for all of your contributions and hard work.

James

PS I noticed that pins 4 and 11 were swaped with power on the eagle and original schematic. This proved to be a little problematic.

   I too am wondering the vales for D3.
   Does anyone have the answer?

Has anyone got PCB's available for this design?

Hi All, has anyone cut PCBs from isabella's eagle files for the PPM meter?

Do you have any available?

If so please indicate here on the wiki, If I dont hear a response here in 2 or 3 weeks, this will give me time to build up a bread board version to see if I can multiplex probe inputs with a 4067 or 4050 and to add this to the 2650 MEGA designs ,same story on PH probe circuits , the general Idea is to have a Open Circuits PCB already setup compatible with the arduino bootloader that can then be used to monitor PPM/PH in Artificial reef scenarios or to control medical/recreational Hydroponic setups(that being said I am lazy I prolly wont go through all of this if PCB's for the PPM meter are available to populate :)

gwen

Btw this design http://www.nano-reef.com/forums/index.php?act=attach&type=post&id=91001 supposedly uses both the PPM design and the PH design by isabella incorporated with a ATMEGA644P/1284P PDIP and through hole design for easy hand soldering. Check the forum for author and Creative Commons licensing Commercial Exploitation encouraged!!(needs to be multiplexed and relaid for smt assembly).. gwen

Any updates? I'm seeing lots of started projects, but nothing completed. Not that that's unusual, my life is one series of unfinished projects after another. But I'm really curious to see if anyone has come up with an elegant design that is reliable and durable. I'd like to see an Arduino shield that could be used to automate hydroponic farming. One of the barriers for entry for small-scale urban farmers (one of the reasons the vast majority of hydroponic produce comes from a single farm in Arizona) is the complexity of balancing the indoor climate (temperature, humidity, air movement, ventilation), the timing and intensity of supplemental lighting when the days are short (and hot lights interacting with the climate), and then the water and chemistry and pollination. The commercial control systems available are outrageously priced, clunky to use, unscalable, not networked, and not comprehensive. You end up with several independently controlled but physically dependent systems and the whole thing gets very touchy. Not to mention pollination, which has to be done when conditions are just right or else you're wasting effort and tiring out your bumble bees (or wearing out your Sonicare toothbrush if you're really small scale like me). -Mike 71.237.45.1 14:53, 14 June 2011 (EDT)

Conductivity meter kit

I like what youve done and want to see more. I did play extenssivly with my own little design and soon i will post the schematics. My tds meter operates on a single 9 to 16v dc supply or even 9 volt battery. PCB and a kit is available for purchase if interested. My tds meter measures 0 to 200 umhos with stainless steel probes ( i used ss screws) or 500 to 5000 umhos by using graphite tips. Out put voltage for 0-200umhos is 0 to 200mv (i used a digital lcd voltmeter display ,works perfect) 500-5000umhos 0-5v . Design uses single chip tlo64 op-amp.