So a friend of mine at work today showed me a cool app from the Android Marketplace that allows you to scan all of food products' bar codes and it would keep track of everything you had in your pantry/fridge, etc. and it would warn you about expiration dates of that food. It had recipes and would suggest things based on what food you had, tell you when you needed to buy more, tell you what stores had it and where they were located, coupons available through those stores, upcoming ads, etc. Pretty cool app. Anyways, that got me thinking about how bar codes work. I always wondered how to interpret them. Well now I know and its quite fascinating. How UPC Bar Codes Work: http://electronics.howstuffworks.com/gadgets/high-tech-gadgets/upc.htm. How Bar Code Scanners Work: http://www.carolinabarcode.com/how-barcode-scanners-work-a-69.html. I'll let you read the articles yourself, but the cool thing about the bar code system is how they were designed to account for every possible situation that might cause a uniform system to break. Think about it, if you just used the numbers which the bar codes represent, it wouldn't work upside down, sideways, or any other position. The genius behind bar codes is existent in several forms.
1. It looks the same no matter where you scan it. You can scan it at the top, bottom, in the middle. It looks the same throughout.
2. It uses binary to convey its message (black and white; 1 and 0)
3. It has a variable checksum digit based on a standard algorithm (uniformity with flexibility). This allows it to be scalable, although it may need to be reformed if there are too many products using UPC bar codes
4. It has a start and end position telling the program when to start reading and when to stop.
5. It uses the reflective properties of the white spaces and the absorption properties of the black spaces to covey its message. Very old school and very effective.
Its just amazing what a mundane and yet commonplace technology has behind it. I hope you enjoy the articles and learn something from them. I certainly did.
No comments:
Post a Comment