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I am working on a single board computer that I am aiming to last for up to 30 years. It will be based on this design, with a lm7805 voltage regulator circuit and address + data line LEDs. I am concerned about the following:

EEPROM Data degredation: I will be using an AT28C256 EEPROM, a chip I know is susceptible to data degredation over the years. I could use PROM, but that is rare and many chips sold as PROM are simply EPROMs with no erasure window. This computer should last much longer than the website with the HEX files.

Electrolytic capacitor lifetime: the electrolyte in an aluminium capacitor is known to dry up over time. The computer will be in an enclosure and the capacitor will be close to the voltage regulator, which will generate heat. If the capacitor leaks, it will seep into the holes on the breadboard (I have no intention to ever manufacture more than one, so I am using a breadboard to save time and money.) and damage it.

Communication standard obsolescence: Go online and buy a new laptop with a serial port. You can't! 15 years ago, every computer had a serial port, some even two. Will USB 4.0 or whatever we will use in the future be backwards compatible?

How can I minimize or eliminate these problems? Cost or size is not a major concern and again, there is no intention to volume manufacture.

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  • \$\begingroup\$ I would not put on a breadboard anything I wanted to last for 30 years. \$\endgroup\$ Feb 22, 2015 at 18:48
  • \$\begingroup\$ I cannot solder all those pins reliably and without solder jumpers. I'm very young. \$\endgroup\$
    – user60684
    Feb 22, 2015 at 18:50
  • \$\begingroup\$ That just means that you require practice. Prototype it on the breadboard, and then move it to a PCB when you are able to. \$\endgroup\$ Feb 22, 2015 at 18:51
  • \$\begingroup\$ Do you mean stripboard or a custom-made PCB? \$\endgroup\$
    – user60684
    Feb 22, 2015 at 18:52
  • \$\begingroup\$ Honestly, it doesn't matter which. You could even go wirewrap if you so felt like it. \$\endgroup\$ Feb 22, 2015 at 18:54

1 Answer 1

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EEPROM Data degredation

My first call here would be to move to a EPROM, even without a window. They're much more sturdy than EEPROM or flash. Failing that, see if you can get one of Atmel's space grade EEPROMs, which will likely be more resistant to all sorts of things.

Electrolytic capacitor lifetime

Start with a good capacitor in the first place, Nichicon or Panasonic. Or use a polymer electrolytic, but that will require soldering.

Communication standard obsolescence

Logic level UART. 9600 or 115200 bps, 8 data bits, no parity bit, 1 stop bit. You'll be able to talk to it almost forever.

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  • \$\begingroup\$ I'm OK with a little soldering, I can't do hundreds of pins. \$\endgroup\$
    – user60684
    Feb 22, 2015 at 18:57

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