Al is correct about this. When I first worked for a barcode scanning company I was taught about the counterintuitive scan performance of wand readers...if you can read a barcode with it, scan faster. I'll never forget being sent off to a conference soon after learning that trick -- in those days (now, too?) you would go to an exhibitor's booth and they would scan a barcode on your badge to quickly capture your contact information...I watched this one guy not get a "good read" and progressively (and intuitively) slowing down his scanning. I jumped in and told him to scan it faster and it made my day to have it work right away (hopefully it made his day easier, as it isn't easy doing the grip-and-grin on your feed for ten hours).

I'd predict that there is a sweet spot speed for mag stripe/wand readers -- too slow or too fast won't work. Hopefully they are tuned to work at human speed...but I suspect "cost" plays a factor, too!

AND ANOTHER STORY....at this same company they had a retail scanner (of the type mounted in a check-out counter) and this scanner was facing some competition from a low-price scanner. There wasn't time to re-design our scanner and we needed a response...I think Marketing came up with the idea that we would slow down the speed of the laser sweep/scan (by futzing with the motor control to slow down the motor)...the point was that this would decrease/cripple the scanner's reading capability performance and thus we could then "justify" a lower price point for the product...even though it was essentially the same scanner. I remember that us employees were up in arms and the president himself had to meet with the lot of us and explain why it made sense to cripple the unit. In the end, I don't think it sold well and don't think it did much to provide a stopgap, but I do recall that for certain types of barcode and in certain reading situations the crippled unit would actually read better than the higher-priced non-crippled unit -- but the variables in that problem are more complex than in a mag stripe reader or a wand scanner (where sharp edge transition is key to good decoding).

Anyway, I understood enough about the business of bar code scanners and the whole optical/analog detection front-end is pretty close to magic.

What’s all this Blasphemy Stuff, Anyhow?

Bob,

For what its worth, I am a Christian and was not offended by your invocation of a Christian theme in teaching a lesson on input impedance. A parody is designed to make the person or subject in question seem ridiculous, either for purposes of criticism or just for humor. Your lesson did no such thing, so I don’t believe that it can accurately be called a parody. I suppose its possible that someone could get the idea that you were equating yourself to Jesus in as much as it was really you teaching the lesson, and … well you do have that bushy beard. Of course, I don’t for a minute think that’s what you intended, and I doubt that anyone else would really come to that conclusion. I believe that this is actually a Third Commandment issue. “Thou shalt not take the name of the Lord thy God in vein:” is taken by many Christians to mean, “Thou shalt not invoke the Divine in any form, outside the context of sincere reverence.” While I understand this point, I believe that one can be overly zealous in pursuing this ideal. The primary mission of a Christian is to bring souls to Christ through the spreading of the gospels. With all due respect to Mr. Rivera, I don’t believe this interest is served if we (Christians) condemn a person over the use of a relatively benign reference to scripture as was employed in this case. If anything it seems an opportunity invite a positive interest with some comment like “Yup, those Pharisees didn’t stand a chance against Jesus did they!” Keep teaching us with that delightfully entertaining twist Bob, and God bless you.