USB-board with one I/O port recommendation or ideas?

[Alias A]

Hi!

This message could be in wrong place, but... I have trying to find USB-board where have only one (1) I/O port for measuring low DC voltages. Do u have any suggestions or something that u have used?

-Thx-

[Henrik_Volkers]

Well, what else are your requirements? 

OK, mostly price (+time to have it run) sample rate, resolution? 

The cheapest without DIY (VCO with soundcard input) I found is this RS232 12bit Device that needs another $10 for a USB2RS232.  

However, I wouldn't start below a NI USB-6009.

[Alias A]

Hi Henrik. Thx for ur message. I Have used USB-6009, but it is too good for this purpose :). Needed only one input for measuring millivolts. Sample rate doens't need to be quick, because port is measurred only once in a while... therefore must be lowcost.

Thanks for the link. I will consider that one. 

-A A-

[Petterik]

Hi Alias A,

How about NI USB-6008. It's cheaper than USB-6009 and it's suitable for measurements which are not needed to be done very fast (Sample rate 10kS/s). Are you 100% sure that you do not need any extra Ai channels in future. With this card you would have 7 SE or 3 DIf Ai channels, 12 DIO channels, 2 Ao channels and one counter (for edge counting) left for future use.

NI USB-6008 

https://www.ni.com/en-us/support/model.usb-6008.html

Best Regards,

Petterik

[Henrik_Volkers]

A A,

depending of your soldering skills, needed resolution, I would go with a VCO (voltage controlled oscillator) and the sound card input.

Or take a look for (the cheapest) handheld multimeter (ebay?) with rs232 output (and again a usb2rs232). Might also be useful in the future 😉

BTW what is generating you DC signal?  If you can make it an amplitude or frequency depending AC signal in the range of 20Hz-20kHz you can use the build in soundcard.