Magnetic Core Memory for Arduino

Call this more of a nostalgia project, but I've designed and documented a simple circuit that use an Arduino Nano to magnetically flip a ferrite core between 0 and 1 state and read back the result. It's just a one bit memory, but the design is easy to scale up to larger arrays. With a little experimentation you might be able to adapt it to read a surplus core plane, such as those sold on eBay. For more on my project see:

I suppose this it the kind of project that only someone who worked on computers back in the day when a "core dump" actually meant what it says, but perhaps it will be educational for the later generation, too.


Nice writeup. Very educational too.

Practically, I think your approach might be useful for constructing a mechanical pixel-board, kinda like the ones they used to use in train stations to indicate destinations and which would chatter loudly as each “pixel” flipped between black and yellow. No need to sense, of course, but I think those pixels are awfully close to cores in principle.

Check out our new shield:

Very cool project and well documented. I worked as a field service engineer on minicomputer systems in the 70s, so I was well versed in core memories of the era. They were very reliable and only thing I ever found bad on just a few occations was a bad sense amp. As long as one had good diagnositic test software, memory troubleshooting was pretty simple and straight forward. We also offered semiconductor memory options at the time also, however core memory hung on for more years then most expected, as the early semi boards didn't have much speed advantage, cost more and didn't offer much capacity improvement per board until much larger 16k dynamic memory chips became avalible in the late 70s.

Thanks for the memories (is that a pun) ;) ?


On a tangential note, in the course of learning about how magnetic core memory works, I stumbled across an article on how later model Seeburg jukeboxes (the ones made between 1955 and 1978) used magnetic cores to record the selections a user made. Apparently, pressing the 'B' and '7' buttons, for example, would send a current through a particular core and magnetize it. Then, as the player head scanned across the records from side to side, it would read out the state of each core and stop when it found one that was written. Seeburg called this the "tormat" module and there is more on how ti worked it here:

Al those years popping spare change into jukeboxes and I never realized it used magnetic core memory...