Interfacing with a PH sensor

[Scozza]

Hi peeps,

I want to try & interface a PH monitor of some sort with my iobridge.  This will be used to monitor water quality in an aquaponics setup.  Has anyone done anything like this?  Ideas would be welcomed (-:

Cheers,

Scozza.

[electroman]

Hi,

Any pH electrode/meter with an analog voltage or serial data output should not be a problem to interface to the iobridge.  You are going to need to find a meter that has analog output (or RS232),  I doubt you will find a suitable electrode/meter pair for much less than $100.

Your main problem will be displaying the data.  If you want to use the datalog widget, at the moment there seems to be no way of converting from volts to pH using the necessary linear calibration equation.  You can do this with a serial API or serial web services API and a serial interface board but you will need a micro, programmed to convert mV to pH.  In this case I don't know if you can easily graph the data on your web page in the same way the data log widget does it.  This is an issue for me because I have a number of sensors, such as wind speed, solar radiance, soil moisture and water level that I would like to monitor using the data log widget.


Cheers

[iobridge]

We are working on custom scales. We don't have a timeline yet, but it is on the list.

[Scozza]

Thanks electroman.  I have found a couple of sub $100 (US) sensors with analog output.  I'm thinking about a simple arduino sketch to monitor the input voltage and to give me a nice simple output to monitor through iobridge (-:  Chart output would be great but I would settle for an upper and lower alarm threshold notification to let me know if anything bad happens whilst I'm not at home.  I'll need to keep an eye on the PH daily for the first 12 months or so until the system stabilises.

Cheers,
Scozza.