On 9/27 Paul Orselli of the Ann Arbor Hands-On Museum wrote:

>Does anyone have leads on interactive Bar Code components >that get at the
idea of how bar code readers actually work?  >(As opposed to something that
bleeps and blinks after you >pass fake grocery items over a scanner). Please
reply via >the list or directly to my e-mail.

Paul...
The automated highway toll collection systems now being implemented in
several states (including Massachusetts), are derived from the
boxcar-tracking schemes long in use in American freight yards. I would think
that several of those equipment manufacturers might have exhibits developed
for use at industry trade shows. Try Thomas' Register.