It may be a failure but it sure does look cool. [Scott Lawrence] had a fair number of EPROM chips on hand and decided to get rid of the traditional eraser and programmer in order to play around with the concepts using his own hardware. He was met with disappointment at several steps in the process. No worries though, each of these upsets sent him back to the drawing board and he learned way more than he ever would have if it had actually worked. It’s fair to say this failure was highly successful.
You’ll want to check out both posts revolving around this hardware. The initial idea came when looking through the transparent crystal on the top of the EPROM chips. The die inside looks like a tennis court to [Scott] and he started wondering what the bits themselves look like as they are reset by ultraviolet light. He conceived of an Arduino add-on board that could both read and erase the chips. The I/O demands of this design led him to actually fabricate a daughter board to use with the MUX shield for Arduino. This is fail number one as the workings of that shield didn’t fit the needs of the project. The redesign also had him scratching his head, but eventually he ended up settling on the use of some shift registers to expand his pin count.
With that design idea he forged ahead, building the Arduino shield seen above. Those part numbers aren’t the shift registers you’d expect. He ended up going a bit different route by salvaging these 74LS393 chips from an old Amiga add-on board. This worked like a charm. The dual UV LEDs for erasing the chip didn’t work even a little bit. His dreams of visualizing bits as they are erased have been dashed, but he does look on the bright side that he now has a way to read EPROM using an Arduino.
Fail of the Week is a Hackaday column which runs every Wednesday. Help keep the fun rolling by writing about your past failures and sending us a link to the story – or sending in links to fail write ups you find in your Internet travels.