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I have never had the need (and probably never will) for a device that could measure the amount of salts in a solution, but I found the circuit to be very interesting. This EC TDS PPM Meter project provides all the information you need to make your very own.
"TDS is the measuring of the amount of salts in a solution. For alot of applications the amount of salt is indicitive of the levels of other stuff in a solution. TDS/PPM meters sold for gardening and aquariums figure the amount of salt in Parts Per Million by measuring the Electrical Conductivity of the solution under test. So a PPM/TDS meter is a EC meter that converts the EC value into PPM values. There were alot of design considerations such as needing to pass a minimum amount of current and voltage thru the solution while keeping a good s/n ratio. But most most important it had to use stuff i had laying around the house and be pretty accurate. The circuit outputs a DC voltage equal to the EC value of the solution being tested. So like 4v on the meter means an EC of 4, 2v means EC of 2, .5V = .5 EC blah blah. To convert EC value to PPM just multiply by 500, so like 4 EC = 2000PPM, .5 EC = 250PPM. Also the output can be connected to an A/D converter without alot much grrrrr."
Thanks Momo |
January 21st, 2008
TDS (Total Dissolved Solids) is used to measure the “strength” of coffee. Strength as amount of coffee in suspension not taste. Taste has a whole nother set of measurements.
I should build this one up so that I don’t have to buy another meter for when I drop the one I got.
Bob
January 21st, 2008
Wow, now THAT article title is alphabet soup.
January 21st, 2008
A bit of acronym soup I guess…
January 22nd, 2008
This is what i have been looking for. Thank you
Http://thesundaybong.com
January 22nd, 2008
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June 18th, 2008
Hi,
I saw with great interest your circuit for EC/TDS Measurement. I am currently working on my own project for automating hydroponic nutrient mixing. I have all the experience necessary on the software side but unfortunately I have no experinece on the electronics side. I was wondering would it be possible for me to purchase an assembled EC/TDS and a PH board from you.
Regards
Gareth Rolles
August 20th, 2008
i will add a pic and display and there you have a stand alone unit
November 12th, 2008
hello i am also looking for a pic controller for ph and tds for hydroponic growing
thanks david
November 12th, 2008
hello it has to be a very low cost unit i am able to help my email is eandaindustries@aol.com
November 13th, 2008
Hi David,
The plans are here. It would be very cheap to build.
http://www.octiva.net/projects/ppm/