Add pH, ORP, Dissolved Oxygen, and Conductivity

Expansion modules and attachments
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lukeluke
Posts: 88
Joined: Mon Apr 04, 2011 4:12 am
Location: Rome, Italy

Add pH, ORP, Dissolved Oxygen, and Conductivity

Post by lukeluke »

Hi,
with my firends, we seen this http://www.atlas-scientific.com/Arduino-ph.html

With this interface we can add other probes like PH probe, ORP or other.

What do you think ? Is possible ?

can we use one of the Temperature input or ATO for connect this interface ?

Thanks

Bye
rimai
Posts: 12881
Joined: Fri Mar 18, 2011 6:47 pm

Re: Add pH, ORP, Dissolved Oxygen, and Conductivity

Post by rimai »

You would only be able to attach one of the modules. Unless you create some sort of multiplexing.
It uses the serial port.
Roberto.
lukeluke
Posts: 88
Joined: Mon Apr 04, 2011 4:12 am
Location: Rome, Italy

Re: Add pH, ORP, Dissolved Oxygen, and Conductivity

Post by lukeluke »

rimai wrote:You would only be able to attach one of the modules. Unless you create some sort of multiplexing.
It uses the serial port.
On the serial i have a wifi... if use a multiplexing can attach it ?

With the multiplexing, the code .pde or other for the wifi change ?
rimai
Posts: 12881
Joined: Fri Mar 18, 2011 6:47 pm

Re: Add pH, ORP, Dissolved Oxygen, and Conductivity

Post by rimai »

That would actually require a hardware multiplexing with the help of an ATO port to control flow and then you would have to code the multiplexing scheme in the libraries.
Another solution would be use two ATO ports and try to configure them as soft serial port, but I've never tried and wouldn't be able to confirm it would work.
http://www.arduino.cc/en/Tutorial/SoftwareSerial
Or, you could wait for my expansion module to come out.
I can almost be certain that even if you do get to be able to make it work, it would give you erroneous reading because of the module not having galvanic isolation.
I can't say 100% because they did not offer a schematics of the circuit they are using, but the delay on releasing the additional probe modules has been in isolating signals so they don't interfere with each other.
I don't want to be the grumpy guy and try to discourage you from using alternative ways. I think it would be good to have different options, but the isolation is the problem I've been trying to deal with for quite some time and I think I finally got it to work the way I want.
If you ever go this route and get good results, please let us know.
Roberto.
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