DIY Conductivity Probe/Meter

I see lots of ppl promoting their tanks and set ups as being one of a kind ,why cant I ?

I do not hink he is complaining about the promotion, but we are all here to learn from each other to improve this hobby. Can you post your schematics for us to learn from? I would love to see them.
 
It is an open source when someone emails me or shows interest SIR...so far i got nothing but bunch of bickering from you . Yes i kept my nickname oemtds which means nothing but a tds.Besides does that web link look like a business page to you? I see lots of ppl promoting their tanks and set ups as being one of a kind ,why cant I ?

I am not bickering, I am telling you that your posts appear to be in the spirit of promoting a product not sharing your work. Furthermore, a simple search of your name "OEMTDS" shows similar posts and numerous reef, hydroponics and similar forums where you offer kits and customization of conductivity products. In most cases you have been banned for solicitation.

OEM (as you know) stands for Original Equipment Manufacturer. So your name appears to indicate a commercial interest in design and sale of TDS measuring equipment.

You have come here asking questions regarding the needs of our hobby, yet your porfile indicates 10 years of experience in our hobby. I would think that If you had 10 years experience in the hobby you would know the needs of the hobby.

You have indicated that you are not trying to sell anything, but the wording of your posts and website (along with your name) appear to indicate that you wish people with interest to contact you so that you can arrange a transaction to customize a product to their needs. Furthermore, some of your pages (not linked here) do list product pricing and a shopping cart for the exact same model you have posted at your "hobby" page. In all of those forums that you have posted to, not once have you posted your "open source" design. Instead you simply posts links back to your site, in some cases even acting like it is not YOUR site, but one you hav stumbled upon that can help others.

I am calling your bluff OEMTDS. You say your project is open source, then post it here so that we can comment and/or benefit from the work as a community. Many of us are electronics hobbyists and/or designers and would welcome the dialog. If on the other hand you are looking to generate private transactions via email (or other means), this is the wrong place.
 
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OEM, how many electrodes does your unit use?

What about temperature?

I wouldn't want a sensor that did not innclude temperature, and I'd strongly prefer 4 electrodes. :)
 
Cyrus,

I tried to reply to your pm but it said that pms are not being accepted.

But to answer your question, from what I have researched so far I was thinking of going with the arduino and ATMega324. Is that a good choice or would you recommend something better? I was also looking on sparkfun and like the idea of using the touch screen shields for the display.
 
A100s.JPG



Here is what i have . It is a single chip op amp based circuitry with stable ac drive source . Range is configured with a gain resistor .Output even though says 3vdc(for 3000micro/S) can be 0-5vdc (0-5000 micro/S) suitable for arduino or any other microprocessor analog input. My complete sensor has this circuit board and 2 graphite electrodes already connected to 1/2" pvc. Now if you choose to have your own sensor connected to it, you can do so.Termp compansation resistance has to be some where arround 2.5k PTC. Default value is 2.5k resistor soldered on the board.My question was ,as i read your comments ,you want to control some where from 0 to 50000micro/S ?
Thats impossible. Here is why
1. if youre using graphite electrodes...you may get good readings at high tds but it wont be accurate 0-200micro/S .You have to use stainless steel.
2. Unless you have a trimpot which will change the gain of the op amp between high and low to manupulate range ,but thats not gooing to be accurate. Not practical.

In this circuitry you have to choose appropriate gain resistor for ranges 10s .100s or 1000s.
 
OEM, how many electrodes does your unit use?

What about temperature?

I wouldn't want a sensor that did not innclude temperature, and I'd strongly prefer 4 electrodes. :)

its a 2 electrode not 4. I know 4 is more favorable.
Has temp comp and based on my tests it produces 2% change from full scale from room temp to lets say 100F.Accuracy is about 4% from full scale . Overall its a good device for $40 which measures and provides dc output for arduino.What more can you ask. I know there are commercial high end $2000 instruments. This is not one of them :).
 
Thats impossible. Here is why
1. if youre using graphite electrodes...you may get good readings at high tds but it wont be accurate 0-200micro/S .You have to use stainless steel.
2. Unless you have a trimpot which will change the gain of the op amp between high and low to manupulate range ,but thats not gooing to be accurate. Not practical.


My commercial conductivity meter (Orion 128) has several selectable ranges, spanning well beyond what you are quoting, with a single set of electrodes. So it is not impossible, but perhaps not a simple DIY. Not $200 either, but perhaps not a DIY.
 
Forgive me for being blunt, but I still don't see a schematic, bill of materials or construction instructions. I just see a person attempting to generate business interest without providing DIY information.

I too can label an image and provide information about it without providing construction details, schematics or a bill of materials. Below is SBC type PC used in a car MP3 Player.

mobo.jpg



Are you going to share the full plans for the project or not?
 
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Yes Randy your "commercial" meter has selectable ranges(aka changes resistor values) but have you tested see if it will read DI water and then 50000Micro/s dead on? If it does great. Mine is not a commercial product nor it costs $200.
Anyways i showed what i have made . So far i see sheac12, cyrusthevirus constantly asking BeanAnimal to show his project but for obvious reasons its on hold.
Instead he 's showing whats inside his mp3 player hahaha.
Anyways you guys are too much fun.
 
Randy ... you are correct ...Perhaps i can add a selectable switch to change the range on mine but i always thought for low conductivity stainless electrodes work best. What kind of tips does your electrode have.?
I hope we are talking about inline continuous monitor verses lab model.
Mine is inline type that provides 0-5vdc to arduino and from there you can customize from touch screen control panel with tons of parameters to mobile ,txt and so on. And all that cost me $40.
 
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Yes Randy your "commercial" meter has selectable ranges(aka changes resistor values) but have you tested see if it will read DI water and then 50000Micro/s dead on? If it does great. Mine is not a commercial product nor it costs $200.
Anyways i showed what i have made . So far i see sheac12, cyrusthevirus constantly asking BeanAnimal to show his project but for obvious reasons its on hold.
Instead he 's showing whats inside his mp3 player hahaha.
Anyways you guys are too much fun.

Here is the problem OEM, Your just trying to leverage a fish forum to drum up business for the products you SELL. You keep avoiding the questions and acting like your one of us, you are not. The fact that I have not posted a working project has no relevance to YOUR actions. I don't (and never have) had anything for sale, you do and can not post a project or plans because I don't have one to post yet. Are you going to post your schematics, bill of materials and construction plans or do I need to send you money via PayPal first?

You act like a planted aquarium hobbyist, and a hydroponics hobbyist, and anything else that will help garner intersest in your "non commerical" kits. You get banned and then move on to the next forum. What is funny is that you think playing these games somehow makes you different than any other spammer who comes here looking to solicit sales for his or her products.
 
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Here is the problem OEM, Your just trying to leverage a fish forum to drum up business for the products you SELL. You keep avoiding the questions and acting like your one of us, you are not. The fact that I have not posted a working project has no relevance to YOUR actions. I don't (and never have) had anything for sale, you do and can not post a project or plans because I don't have one to post yet. Are you going to post your schematics, bill of materials and construction plans or do I need to send you money via PayPal first?

You act like a planted aquarium hobbyist, and a hydroponics hobbyist, and anything else that will help garner intersest in your "non commerical" kits. You get banned and then move on to the next forum. What is funny is that you think playing these games somehow makes you different than any other spammer who comes here looking to solicit sales for his or her products.

well said
 
Excuse me but this thread is about conductivity meter isnt it?and i share my thoughts just like anyone else,no one is pushing you to buy anything. its ok i forgive you BeanAnimal.
 
I worked with the one located here, http://www.octiva.net/projects/ppm/ but it was hard to understand. I tried to reach out to the person, but never heard back from them. I also wanted to include the - 12 VAC conversion in the board so I only needed to suppy 12 VAC instead of + and - 12 VAC.

Unfortunately I do not have a scope.

The probes I purchased from China. The range should work for saltwater, but I will not know until I get a working prototype.

PM me on the PCB if you are interested. I think I have 6 or so extra ones.


cyrusthevirus there is an easier way to generate -12vdc with far less components , i will email you the schematics.
 
Dont be hostile BeanAnimal just because someone smarter than you talks about real issues instead of promoting HM products . Because of you i may get banned (no sweat) but you are here to keep folks in your limited narrow circle of products made in Korea.
 
well said

Correction

I am avoiding YOU because youre the only one that acts like an umm how should i say this (OEMTDS fan) that for some reason i dont know what it is ,perhaps youre scared of competition? or lack of knowledge about how conductivity circuitry works , i dont know..whatever it might be ,you try to divert from the real subject and poison the room.
 
Cyrus,

Any chance of you releasing the eagle and BOM files to the salinity reader?

I can not believe I actually found these. It took a lot of searching:

BTW I have some extra PCBs of the circuit if you are interested.

BOD
R1 1K
R2 1K
R3 56K
R4 33K
R5 100K
R6 1K
R7 6.8K
R8 22K
R9 1K
R10 220K
R11 220K
R12 220K
R13 100K
R14 100K
R15 82K

U1 TL074
V1 100K
V2 2K
V3 22K

C1 .015uF
C2 .015uF
C3 .22uF
C4 3300uF
C5 3300uF
C8 1uF
C6 3300uF
C7 3300uF
C9 1uF
C10 1uF
C11 1uF

D1 1n4733A
D2 1n4733A
D3A 1N4148DO35-10
D3B 1N4148DO35-10
D3C 1N4148DO35-10
D3D 1N4148DO35-10

CR1 1N4004
CR2 1N4004
CR3 1N4004
CR4 1N4004
CR5 1N4004
CR6 1N4004

IC1 LM79L12
IC2 LM78L12

X1 BNC PCB connector
X2 Phoenix CONN TERM BLOCK 4POS 5.08MM PCB
X3 DUAL LEAF DIP SOCKETS 14-pins

12VAC 500MA
 

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