USB pH sensor

[chucklawrence]

Has anyone tried using pH sensors that hook into a pc or mac?  Like this one for example: http://www.vernier.com/products/sensors/ph-sensors/ph-bta/

[IllinoisCheeseHead]

Hi

Nice probe.  I would be concerned with such a high range inaccuracy.  They are saying .02 plus or minus.  That means you could be off by .2 either way from actual numbers.  Since .1 translates to 10 times more acidic or more alkaline, being of by .2 would be far more than I would tolerate

Thanks

[chucklawrence]

Yeah, I don't really mean this EXACT one but a pH probe that hooks in via USB

[Kern]

Here are the specifications copied from the link you furnished:

    Type: Sealed, gel-filled, epoxy body, Ag/AgCl   
    Shaft Diameter: 12 mm OD   
    Response time: 90% of final reading in 1 second   
    Temperature range: 5 to 80°C   
    Range: pH 0–14   
    Accuracy: +/- 0.2 pH units   
    Isopotential pH: pH 7 (point at which temperature has no effect)   

I read the accuracy to mean that with an actual pH of 5.5 this unit could read it as 5.7 at one test and then 5.3 a few minutes later.  That's what +/- 0.2 pH units means.  For cheese making you've got to be down into the +/- 0.05 pH unit accuracy range with appropriate reproducibility in the same range. 

I have no objections to using a USB probe so long as it is a good pH meter.  The one in your link is not a good one.   

[jmason]

I looked after reading your post and cheap chinese electrodes, that sell for like 8 bux and get the same or better accuracy, only difference is the bnc connector rather than usb.  USB is not magic, it's a serial interface with a 5 volt power supply.  So for a fraction of the price you could rig one up with an arduino or raspberry pi and I'm betting someone has already written an open source code for both units to display and/or datalog.  This unit did not come with interface or software, the interfaces they listed almost doubled the price.  Personally I'd persue a better option.

[Gürkan Yeniçeri]

I think it is not necessary to attach a USB pH sensor in to my VAT. This would have been good for an aquaponics though.

For cheese making you can always learn titratable acidity on this thread or after couple of make you will get the idea by the texture of the curd anyway.