Scientific RPN Calculator (with ATTINY85)

[Chasfield]

Well done! An excellent low cost project and a quick win for those not confident in scratch building their own hardware.

The keyboard is always the problem. My last approach was to conjoin two soft-action, 16 key pads. This actually worked out very well and was easy to label. That project, and others, are outlined in my RPN-duino thread under "Not quite HP Calculators".

Re displays: 64x128 OLEDs, with 4-line I2C connectivity are great but they are a bit RAM hungry with respect to 8 bit micro-controller platforms. This was not an issue for my ARM based Arduino Due project.