Data Acquisition newbie question

[Brian Dessent]

Don DRI05 Ricciardiello wrote:

> Thanks for that lead, looks promising. Another question if  I may. Does the
> DataQ Starter kit unit have to stay connected to the PC during use? If so
> that's gonna prove difficult on the bike!

I've never used this product.  But in all likelihood for $13 you are not
going to get any sort of data buffering whatsoever, so yes, it would
have to be connected to a laptop or PC while in use.  From their picture
of the board it looks like it's not much more than a serial ADC with a
clock generator, serial line driver, and voltage reference.  Based on
the 240 samp/sec figure I'm guessing it talks at 9600 baud.

If anyone is interested in other cheap data-acq stuff, for $60 you can
get a similar unit from B&B electronics.  This model also connects via
the serial port (and is port-powered) but has 11 channels of 12 bit A/D,
in addition to 3 digital inputs and 3 digital outputs.  This unit is
also limited to 9600 baud (an arbitrarily low rate if you ask me) and
hence it gets only 120 samp/sec for a single channel and 25 samp/sec if
you read all the channels.  Still, for automotive use these low sample
rated would be fine, esp if you're not trying to do something like
determine injector pulsewidth or calculate RPM directly, i.e. build a
circuit to convert these relatively fast signals into a voltage which
can be sampled at a much lower rate.  They too have data-acq software
available but I have no idea what the quality is like.  URL below:

http://www.bb-elec.com/product.asp?sku=232SDA12


Disclaimer: I have nothing vested in either of these products, in fact
I've never used them... simply relaying some research I did.

Brian
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