POV Fan EEPROM Hack

October 9, 2009 by Mike Szczys 4 Comments

pov_fan_eeprom_hacking

Hacking with Gum got their hands on one of the persistence of vision display fans that Cenzic was giving away at Blackhat this year. It’s not the biggest fan-based POV display we’ve seen but it’s still a fun device to tinker with. They hacked into the EEPROM on the device in order to change the message the fan displayed.

This is very similar to the other EEPROM reading/writing we’ve seen recently. Hacking with Gum read the data off of the EEPROM and then disassembled it to discover how the message data is stored on the chip. This was made easier by noting the messages displayed when the fan is running. The first byte of data shows the number of words in the message, then each chunk of word data is preceded by one byte that represents the number of letters in that work. Data length was calculated based on the number of pixels in each display character. Once he knew the data-storage scheme, it was just a matter of formatting his own messages in the same way and overwriting the chip.

This is a great write-up if you’re looking for a primer on reverse engineering an unknown hardware system. If you had fun trying out our barcode challenges perhaps deciphering EEPROM data from a simple device should be your next quest.

[Thanks James]

Barcode Challenge

October 7, 2009 by Mike Szczys 184 Comments

barcode_challenge

This morning we logged into Google to find a Barcode instead of the normal logo (how strange that Google would change their graphic!). Apparently today is the anniversary of the Barcode. This method of easily labeling items for computer scanning is used for every type of commodity in our society. But do you know how to get the cryptic information back out of the Barcode?

Here’s the challenge: The image at the top of the post was created by the devious writers here at Hack a Day. Leave us a comment that tells us what the message says and explains how you deciphered it. There are programs that will do this for you and some smartphones can do this from a picture of the code, but we’re looking for the most creative solutions.

The winner will be decided in a totally unfair and biased way and gets their name plastered all over Hack a Day (and possibly slandered a bit). So get out there and start decoding that machine-readable image.

Update: We’ve announced a winner for this challenge.