The BIB (basic interface box) got designed for a workshop I gave
under the NSF's Undergraduate Faculty Enhancement program in 1994,
where I showed the various interfacing schemes we have developed
(mostly with NSF support).
I wanted people to take something home and have it plug in and work,
and not need to buy anything else, so the humble little interface
box (BIB = basic interface box) was cooked up.
The BIB has only an 8-bit serial A/D converter, and no gain control,
just 0-6v unamplified. But analog input can also be run to an onboard
amplifier (gain around 500, adjustable by taking off the cover) and
then to the A/D. Data rates are around 1 khz on the clunkiest old
PCs, to around 10 khz on the new ones. The BIB runs from a 9-v wall
plug and sends data in and out of the computer via the printer port.
The BIB will also run a sonic ranger, and a shaft encoder (which
measures angular or linear changes with great accuracy ), and it will
let the shaft encoder work 'synchronously' with the analog input
(every time the angle changes, a piece of analog data is taken). It
works nicely with Vernier's microphone, giving very nice frequency
analysis.
In our department, the BIB is taking on a life of its own. We now
use BIBs for a laser diffraction and interfrence experiment, and BIBs
are used as backups in our labs, when we have a problem with existing
(but aging) interfaces (mainly sonic rangers).
Because the BIB can plug into a laptop, we can do
demonstration-experiments in classrooms where the laptop plugs into a
projection system. And since the students at Rose are getting
laptops as freshmen, there is the possibliity of our using BIBs and
laptops in the future to do physics labs
I wrote the software in Turbo Pascal (except for short stretch of
assembly language for the A/D). It includes FFTs for the analog and
angle data, graphs data and does some 'fitting' by allowing the
user to move lines and parabolas around on the screen.
Anyone interested is should please contact me about the BIB. You are
welcome to the plans if you want to build it yourself, and it can be
purchased through our departmental technician, Gary Burgess, who was
willing to build units for sale when workshop participants turned out
to be wildly enthusiastic about it.
--
Mike
--
Mike Moloney
moloney@nextwork.rose-hulman.edu
Dept of Physics & Applied Optics (812) 877 8302
Rose-Hulman Institute of Technology Terre Haute, IN 47803 http://www.rose-hulman.edu/~moloney/index.html