Bar code scanning reveals wrong data

[Kuma Kato]

I seem to be having issues with barcode scanning in iOS 8.3. When activating the barcode scan feature in the Tap Forms search bar the camera comes up quickly but rarely reads the barcode, just hangs with the camera open ready to read. On the few occations when it does read the code it gets the first four digits wrong and the last four correct, using EAN-8. Code is printed cleanly and camera has a good image of it. Do you have any tips I could try? Only purchased the iOS version for this feature so I could quickly bring up data I entered in the desktop version. Thanks.

[Brendan]

Can you post a sample image of the barcode that’s not scanning?

Is this with the iPhone version?

Does it have troubles only with the search feature or also with the data entry scanning of barcodes?

[Kuma Kato]

Thanks for the reply. Have attached a screen shot of bar code from the Mac desktop version. You can see the 8 digit number assigned in the image. When I printed out and scanned with the iOS version it read the number 11233404. You can see the first four numbers are incorrect and the last four are correct. So far I am just trying to search the database that I transferred from the Mac to my iPhone and haven’t tried any data entry on my iPhone directly. Bar code reader on iPhone seems to have poor response and only works some of the time, and then it reads the wrong values. Have had it get 7/8 numbers correct a few times and once out of over 20 tries it got all 8 correct…haven’t been able to repeat this success since but will keep trying.

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[Kuma Kato]

Update: I switched the barcode generator to UPC-A and now my iOS reader works fine. Same printing and lighting so I’m blaming EAN-8 and moving on. Thanks!

[Brendan]

I couldn’t see the attached file since it didn’t seem to come through the forum, but I’m glad that you found a solution.

[Hans]

I have the same issue, EAN-8 is not recognized by th scanner. I have a collection with printed EAN-8 codes so I cannot switch to another system like Kuma Kato did.

[Brendan]

Hi Hans,

Do you mean the EAN-8 barcodes were generated by Tap Forms and the iOS version can’t recognize them? Or the EAN-8 barcodes were generated somewhere else and Tap Forms for iOS can’t read them?

I just did a test and it seems to matter what the number is that’s being scanned, but it does work when I searched for some valid EAN-8 codes on Google.

Do you have a sample code that you could send me that I could try scanning?

Thanks,

Brendan

[Hans]

I indeed mean barcodes which are generated by Tap Forms. Attached a pdf with such a generated barcode in EAN-8.
If there is an kind of algoritm I can renumber, that is no problem.

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[Brendan]

Hi Hans,

Ok, so it seems that EAN-8 barcodes need to have a check digit added to the end of them in order for them to be scanned properly.

I found a page that describes the Encoding algorithm, but it does take a little bit of math, but it’s fairly easy to understand:

http://www.barcodeisland.com/ean8.phtml

Look at the section under ENCODING to see how it’s supposed to go. Basically with EAN-8 you can only encode 7 digits as the last digit will be a checksum digit.

Tap Forms doesn’t automatically add the check digit. It just tries to generate the bars as it gets the value. Some barcode symbologies don’t require any check digit encoding.

Thanks,

Brendan

[Brendan]

So from that algorithm, you can only encode the first 7 digits of your number as follows:

7002503

7*3 + 0*1 + 0*3 + 2*1 + 5*3 + 0*1 + 3*3

21 + 2 + 15 + 9 = 47

to be divisible by 10, add 3 to 47.

3 is the check digit.

So your final number should be:

70025033

Which scans just fine in Tap Forms for iOS.

Hope that helps.

Brendan

[Hans]

Wow, never knew the magic behind the barcodes, but it works!
Thanks for your help.

[Author]

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