Many of us are calculator enthusiasts (seriously!) and if we can't get the real thing - or for a challenge, it can be fun to emulate an older model with an Arduino. One example of this has been demonstrated by Arduino enthusiast Pietro De Luca with his HP35 emulator powered by an Arduino. Unlike other calculator emulators, Pietro has gone for a real PC keyboard for data entry instead of the small keypads, with the output sent to a typical LCD module. And it isn't as difficult as you would first think, as Pietro has explained the workings of the HP35's architecture ROM and much more.
So to journey back in time and reproduce your own HP35, or just for some interesting reading about older architectures - visit Pietro's website. And for more, we're on twitter and Google+, so follow us for news and product updates as well.