Reverse Engineering Super Animal Cards

If you don’t have a niece or nephew we encourage you to get one because they provide a great excuse to take apart kids’ toys.

[Sam] had just bought some animal-themed trading cards. These particular cards accompany a card-reader that uses barcodes to play some audio specific to each animal when swiped. So [Sam] convinces her niece that they should draw their own bar codes. Of course it’s not that easy: the barcodes end up having even and odd parity bits tacked on to verify a valid read. But after some solid reasoning plus trial-and-error, [Sam] convinces her niece that the world runs on science rather than magic.

But it can’t end there; [Sam] wants to hear all the animals. Printing out a bunch of cards is tedious, so [Sam] opens up the card reader and programs and Arduino to press a button and blink an IR LED to simulate a card swipe. (Kudos!) Now she can easily go through all 1023 possible values for the animal cards and play all the audio tracks, and her niece gets to hear more animal sounds than any child could desire.

Along the way, [Sam] found some interesting non-animal sounds that she thinks are Easter eggs but we would wager are for future use in a contest or promotional drawing or something similar. Either way, its great fun to get to listen in on more than you’re supposed to. And what better way to educate the next generation of little hackers than by spending some quality time together spoofing bar codes with pen and paper?

15 thoughts on “Reverse Engineering Super Animal Cards

  1. Nicely done, Sam :) We did something similar with my niece’s Barbie “CD Player” that uses plastic discs with lil nubs on them to press buttons to give you the pre=loaded songs. We had loads of fun with the hot glue gun making lil nubs and seeing what song would come out of it next :) Similar to your easter eggs, she claimed one of the songs was Belle (i have no clue) and was super excited. Now there is a pile of things to fix every time Unca visits :) She is a pro with the philips head at this point. The adults love the volume pots I add to the toys to give them a range between ear piercing and dead battery lol.

  2. I got as far as trying to scribble the bars on a piece of paper, and then turned one of the “zeros” into a “one”. Nothing happened, but then it looks like I should have persisted!!! ( and used a ruler)

    1. The cards have a small checksum which is why randomly changing a 1 to a 0 won’t work

      From top to bottom
      1 – always a 1 – thick bar. Lead out / stop bit
      2,3 – always 10 or 01 depending on the number of bits used being odd or even
      Then you have binary 1,2,4,8,16,32,64 and 128 introduced in the new set of cards….

      Final two bits are always zero binary bits (256 and 512)
      I suspect it doesn’t go up to 1024 as the last bit (the first one read) will probably always be a zero….or the first two bits read could likley be an initialisation pulse.

      1. If you block the top three bits with your thumb, then get good at remembering patterns you can ask the staff in Woolies to let you search the box for the cards you want…..voila, a complete set!!

        I’ve sent a bundle over to my nephew that is a sealed. Complete set of cards so he gets the excitement of opening them too, there’s 85 packs of cards to get all original 108…..with the exception of number 107 that I could Not find again…one complete open pack, one complete sealed here

  3. I want one of these so bad! Could you print multiple barcodes onto a long strip to sequence an animal beatbox? Maybe tape it into a loop and add a simple motor drive to trigger sequences over and over again? Great- now I have another project to dive into.

  4. The thing with systems like this is they are non-expandable with all the audio built into the device. It’s a higher tech version of the original Magnavox Odyssey game console where all possible games were built in. The “cartridges” were simply jumper boards.

    If they’d put a multi track magnetic stripe on the cards or a high density transmissive optical barcode, with the printing protected by a second clear layer, digital audio could be on the cards and the manufacturer could produce as many new sound cards as they want.

    1. My guess is that 191 card is going to be used for a competition – most card readers will say “Better luck next time” but one or perhaps a few lucky card reader owners will have the special “you’ve won a gazillion litres of Woolworths Home Brand chocolate ice cream to be delivered right to your door tomorrow morning!”

      My card reader, unfortunately, isn’t one of those. Oh well…

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