Erasing chips with a pacifier sterilizer
I recently broke out my micrcontroller gear and have been working on a few projects. I have these old 12F671 chips that have an EPROM in them, not EEPROM, but EPROM. They are windowed so you can erase them with UV light before programming them. They are a pain, but I hate to just leave them doing nothing, so I thought I'd find something useful for them to do. I found my old UV chip eraser, but I can't find the 24VDC supply for it! At lunch today I saw our UV germicidal pacifier thingie. And the gears began to turn!
Google tells me that 264nm is the peak wavelength for destroying DNA. So that must be about what the pacifier sterilizer peaks at. Google also told me that to erase EPROMS, you need about 254nm. 10nm isn't very much and most gas tubes like this radiate a wide spectrum. So the output at 254nm I'm sure will suffice.
So into the paci sterilizer went my 12F671's. The sterilizer has a timer, and after one interval I pulled them out, and they still had data, but some of the data was gone! So I sent them in for another round. That did the trick, both chips were blank after two doses. That's at least as fast as I remember it taking my real UV chip eraser! (It's a cheap one I'm sure).
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I see that http://hackaday.com published this! Thanks guys! Always good to get on one of my favorite websites!
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I'm also seeing lots of comments about lead exposure. I appreciate everyone's concern, but educate yourself a little before you get too excited. Most of the lead in a chip is in the solder used to bond the leads inside to the silicon wafer. This is sealed inside the chip package, and the lead is in solid form. People get exposed when they A. make the chips or B. melt them down for gold and other precious metals. The chips just don't leech lead like an old tranformer leeching PCBs. You don't get lead exposure handling chips, if you did, we'd all be in bad shape as electronic experimenters.
Finally, the pacifier doesn't touch the inside of the sterilizer they way it's designed. I seriously doubt that the lead can jump from inside the chip to the pacifier in this manner.