## calculating conductivity of water by pi

anshuman95
Posts: 1
Joined: Thu Apr 07, 2016 6:40 am

### calculating conductivity of water by pi

hey guys
I have to make this college project in which, I was given to calculate tds and conductivity of water sample. and I have never worked on raspberry before but I have learned how to make a pi read analog values through mcp3008 but what I don't understand is how do I induct my conductivity electrode??

experix
Posts: 204
Joined: Mon Nov 10, 2014 7:39 pm
Location: Coquille OR
Contact: Website

### Re: calculating conductivity of water by pi

I guess you are asking how to connect the conductivity electrode to the ADC. Can you tell us about the electrode or post a link to its data sheet?

brekee12
Posts: 335
Joined: Wed Feb 03, 2016 3:36 pm
Location: HU

### Re: calculating conductivity of water by pi

This is a bit more complicated than connecting the electrode to the ADC. Conductivity measurements based on AC voltage drop measurements. So what you need is an AC current generator and measure the voltage on the electrode or you need precise resistors and measure as a voltage divider. Both cases you need a rectifier between the electrode and the ADC. If it is possible use sinusoidal generator to avoid high freqvency components. The resistance you need to measure is between 10 Ohm and 1 MOhm which is not possible in one range, you need to handle range changes, too.
Brekee12
on a Raspberry B+ with whezzy, two Zero with Jessie Light

liudr
Posts: 685
Joined: Sat Jun 01, 2013 12:11 am
Location: Central MN, USA
Contact: Website

### Re: calculating conductivity of water by pi

Is your budget able to accommodate the correct AC measurement that brekee12 was describing:

http://www.atlas-scientific.com/product ... zo_ec.html

I saw small purple color fruit icons and teal infinity at the bottom of the page.
Arduino data loggers, user interface, printed circuit board designer since 2009, RPI 3B 2B 2B Zero Jessie, assembly/C/C++/java/python programmer since the 80's