Playing store just got really, really fun because you can now build your own LEGO barcode scanner. As you can see after the break, it works well and it’s fast like a real barcode scanner. Unfortunately it doesn’t scan real barcodes. Or at least not traditional ones. As we learned in the Barcode Challenge, standard barcodes are a set of white and black bars that make up the ones and zeros of the code. This system uses the same white and gray bar system but it seems that it’s only the number of bars that identify an item, not a code created by a particular combination of light and dark. The items above are all scannable because the scanner counts the 2, 3, 4, 5 or 6 white beams on the bottom of each package. Still, it’s incredibly clever and a great toy for the young hackers to build if they have a little help.
[youtube=http://www.youtube.com/watch?v=Q6UYW0hwKTg]
[via Tinkernology]
I have found the NXT light sensor to be rather noisy. Getting accurate results at that scanning speed is quite an achievement.
I remember to those old Anarchy tutorials about using a pencil to cheat with barcodes on stuff you buy in the stores :D
Guess that hacking is kinda lowlife drifter level nowadays considering that you can rather find bugs in googles software for 3ks and you dont have to hack barcodes on the cereal to survive.
For a class project we build a crude version of this functionality, too, last year.
We were limited in the amount of parts we could use and had to emulate the entire procedure in an ATM and relied on b/w strips on a credit card. Getting the timing right was so annoying with this sensor that we relied on a motor to pull the card into position. That solution above is really impressive.
http://glokal.eu/content/building-lego-atm-machine
http://www.youtube.com/view_play_list?p=5525D0FFF28C6D3F