OpenBSD has a driver for the Dallas OneWire protocol.
man(4) onewire
Dallas make adapters for USB and RS232, such as the DS9490R - google
can find you a supplier,
for example:
http://www.hobby-boards.com/catalog/product_info.php?products_id=1503
There are all manner of 1wire chips avalable - hobby boards can help
here if you dont want to
build something from scratch.
I havn't used these adapters, nor used 1wire on OpenBSD, nor dealt with
hobby-boards.com, but I
have used a 1wire A-D to read input multiple voltages on a dedicated
system and it works very
well.
It should work very well on OpenBSD too.
paulm
On 29/01/2010, at 9:27 AM, Ralph Becker-Szendy wrote:
For one of my OpenBSD machines, I need to be able to measure a few
analog voltages, and act on them in a control process. The
requirements are quite simple compared to typical data acquisition: I
absolutely need two voltage inputs, either 0-20V or 0-100mV; doesn't
have to be differential, acquisition can be slow (1s is fine), and
resolution can be as small as 10-12 bits (1% accuracy is more than
good enough). A few extra input channels, more accuracy/resolution,
and a few digital IOs wouldn't hurt, but are not necessary. DIN rail
mounting and connection breakout would be nice, but can be improvised.
On the software side, there will be OpenBSD, with ad-hoc monitoring
and control scripts. With a little programming and script-writing, I
can adapt anything that the OS can reasonably access.
Now come the issues: I can't use PCI cards, only external units, most
likely connected via USB (as Ethernet and serial are expensive or
rare). And it needs to have some software support under OpenBSD - a
Windows- or Linux-only solution doesn't work. And this application is
not worth spending thousands of $$$. For Windows and LabView,
solutions are easy to find (for example EMant300, DAQPodMX, a variety
of Omega products). Does anyone now of a solution that would work with
OpenBSD?
--
Ralph Becker-Szendy ra...@lr.los-gatos.ca.us (408)395-1435
735 Sunset Ridge Road; Los Gatos, CA 95033
