USB Data Acquisition Modules

[Roff]

Have any of you used a USB data acquisition module from Dataq? I'm looking specifically at the one on that page, although they have several others.
If you have, I'd be interested in your opinions, and possibly answering a few questions.

 

[Sceadwian]

At 50 bucks the unit seems nice. But the software is a bloody ripoff. You have to purchase 200 dollar softare to allow you to sample over 240hz? That's just not right.
What's your intended use? You could build your own voltage scaleing circuit to allow you to use a PC sound card to sample high voltage AC signals at 44.1khz or higher. I'm sure it's possible to bypass the DC blocking cap on a sound cards input to allow you to measure DC signals. I'd be more inclide to buy some cheap USB sound card 'pucks' that have audio in.

 

[Roff]

My initial application is monitoring charge and discharge currents and voltages on batteries. The first one is a 12AH SLA. I can handle the interfacing circuitry. I have sent off an email to Dataq regarding the significance of buffer size (bits or bytes), and what the source of the minimum sample rate is (I think it's the software).
It's like giving away razors in order to sell razor blades. The software is too expensive, but, at least for now, the free castrated version that comes with the module will suffice.

 

[picbits]

I'd look at something like an FTDI USB/RS232 converter, a PIC and some simple software.

I made something similar a couple of years ago - the PIC just fed a constant stream of data through its serial port which was converted to USB through a cheapo USB/RS232 converter. My front end was a simple Visual Basic program which wrote the values to a file.

Cost for the whole project - less than 10 of my hard earned British pounds

 

[Roff]

I'd look at something like an FTDI USB/RS232 converter, a PIC and some simple software.

I made something similar a couple of years ago - the PIC just fed a constant stream of data through its serial port which was converted to USB through a cheapo USB/RS232 converter. My front end was a simple Visual Basic program which wrote the values to a file.

Cost for the whole project - less than 10 of my hard earned British pounds

Thanks for the ideas.
I thought about building my own hardware, but I have no experience with PICs (soon to change), and I'm in a hurry.

 

[Nigel Goodwin]

Thanks for the ideas.
I thought about building my own hardware, but I have no experience with PICs (soon to change), and I'm in a hurry.

My tutorials have all you need, and include reading analogue inputs and sending them via serial to a PC. It's really very easy to do.

 

[3v0]

You may want to look at a UBW from sprarkfun.

 

[Roff]

My tutorials have all you need, and include reading analogue inputs and sending them via serial to a PC. It's really very easy to do.

OK, thanks, Nigel. I'm seriously considering Blueroom's Inchworm and Firefly, as soon as one of his dealers gets parts in stock. In the meantime, I'm wanting to get on with the battery project.

 

[Roff]

You may want to look at a UBW from sprarkfun.

3v0, that is very interesting. I'll study it carefully.

Thanks-
Ron

 

[Nigel Goodwin]

OK, thanks, Nigel. I'm seriously considering Blueroom's Inchworm and Firefly, as soon as one of his dealers gets parts in stock. In the meantime, I'm wanting to get on with the battery project.

BTW, an 8 pin PIC, such as the 12F675 should do all you need, and provide multiple analogue inputs if required - for a serial 'interface' you can get away with a single resistor (crude but it works fine, because you can invert in the software).