I was pondering the means of how to scan barcodes with an iPad for a while.
Today I found a really cheap solution. Just connect a stock USB keyboard barcode scanner via the camera connection kit USB connector to the iPad, and you’re done.
Now you can scan your book EANs for librarything or other things like price searches. But
as I’m currently working on some iPad business applications – those would benefit even more from this setup.
Now you can scan whatever barcodes your scanner is configured for (EAN, UPC, CODE128, CODABAR,I3OF9). Those USB scanners are also able to send prefix and postfix key strokes in addition to the barcode itself and also other optional information like the barcode type. All that can be used by your app to process the barcodes.
Another alternative that came up today is to use the iPod touch 4G as the barcode scanning device (creating an App that scans the barcodes with the typical barcode SDKs like redlaser or Big In Japan/Shop Savvy).