Simple USB data logger and ph meter

[razorshk]

Hi there,

This is my first post here. I am interested to buy a simple pH meter and hook it up to a usb data logger and use my pc to measure the pH chnage over time in my marine aquarium. Does anyone know how to do it?

It should be like this:
http://www.lascarelectronics.com/PRODUC ... 9B7DC749FB

My plan is as follows:
1. Buy a cheap digital pH meter from ebay.
http://cgi.ebay.com.au/PH-METER-Marine- ... dZViewItem

2. hook up the voltage point to a voltmeter or usb data logger
http://cgi.ebay.com.au/USB-4-Ch-Voltmet ... dZViewItem

3. Measure data and plot some graphs


I was also wondering if there is an amateur aquarium journal where we can publish our results.

raz

 

[Anonymous]

There are a few companies out that with USB-based instrumentation. Check out FisherScientific/Omega and other academic instrument company for high-school class instruments.

The eBay item does not seem to be able to work with a logger directly. You maybe better of gettting one that work as a system with the logger.

 

[das75]

I run datalogger (though not USB) and just have a Pinpoint probe hooked to it, not through a meter.

Seems they are all similiar and fr AMI "probe will generate 59 mV per each unit of positive pH and the opposite will be negative mV. Example pH 7.0= 0 mV; a ph of 8.0=59mV a pH of 6.5= -30mV"


Here's a link to some cheap probes
http://www.aqua-digital.com/ProductDetails.asp?SubCatagoryID=391&ProductID=1095

 

[Anonymous]

There are several USB products that can be easily customized for this type of application.

Activewire USB is a USB DIO module that is very versitile. You may also want to look at phidgets.com or phidgetsusa.com They have very affordable hobby style USB Digital and analog I/O products.

I would opt for an Analog input and use an eBay purchased intrumentation amp to condition the probe output. There is an APP NOTE on the national semiconductor site that describes building a suitable amp, but the eBay route will be much easier.

You WILL need to knwo a little bit of C, C++, VB, JAVA or scripting code to do the logging.