Recommendations for a cheap USB peripheral for PC to measure voltage

I'm looking for a cheap USB peripheral that I can use to collect voltage measurement data. The application that I currently have in mind is to measure battery capacity by attaching a known resistance and then integrating the voltage measurements. This is purely for fun and out of interest.

I would prefer a peripheral that I can access through a USB API like pyUSB. Preferably not something that requires the use of the manufacturer's software/drivers linked to a specific platform; I want to be able to use this on Linux.

Some googling yields interesting results, but most options seem a bit pricey and overkill for what I need (for example the USBee SX). Recommendations?

wcoenen

Posted 2009-09-08T20:27:38.937

Reputation: 2 060

Answers

If you don't mind writing a few lines of code then have a look at the Arduino it's got 6 (depending on the model) analog inputs as well as a load of DIO's and a USB connector that acts as a serial port.

Writing code for it is really simple and theirs lots of examples on the web site. It's a great device and really fun to play with.

Price is good as well, their about £15+ here in the UK or $15+ on eBay.com

Stephen Harrison

Posted 2009-09-08T20:27:38.937

Reputation: 311

The only downside to this is you are greatly limited in voltage range measurement. I believe it can only measure from 0-5V. Of course if all the original poster wants to do is measure 1.5V batteries, this isn't a big deal. Also $15 is a bit low...probably more like $30-$40. – davr – 2009-09-09T00:50:10.130

The voltage range is easy to solve with a couple of resistors, I think it's also possible to push in a different analog reference voltage if 5V is above the max and you want better resolution.

Prices certainly vary, for $40 you can get a Arduino Mega over on eBay (+$7 postage), theirs also a more normal arduino for $12 with free post but the mean price appears to be around the $30, it depends on where you get it from and which model, either way it's cheaper than a lot of the other options and a lot of fun! – Stephen Harrison – 2009-09-09T23:23:34.297

I've ordered. Can't wait to get my hands on one of these babies :-) – wcoenen – 2009-09-14T00:12:41.243

I have a multi-meter that I got at Radio Shack a couple of years back. It's their catalog #22-812. Among all it's measurements, it also has a serial port that can be used for data logging. Get a cheap serial-to-usb adapter, and program away to your heart's content. Obviously the date collection rate will be somewhat limited, as this is a dmm, not a scope. But from your description, I think you don't need high data rates.

Michael Kohne

Posted 2009-09-08T20:27:38.937

Reputation: 3 808

Looks like this is a feature on some of the fancier Multimeters out there. That one is still pretty spendy at $65, but cheaper than the one you list in the original question at least.

If your computer has an old-schoo serial (RS232) port then I found something a bit cheaper as well

Ryan

Posted 2009-09-08T20:27:38.937

Reputation: 1 728