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A RPN (Reverse Polish Notation) calculator of billet walnut case.

There are multi-functional RPN calculators with numbers of small keys. However, daily use RPN calculators with large and light touch buttons are rare. So I made it by my own.
This calculator also has trigonometric, logarithmic and exponential functions. It is hidden but appears on the LCD as function key style by pressing the silver key (or long press of keys).
Comfortable and traditional look made from wood billet.

he schematic diagram and case design depends on what parts you select. The following data (STLs, gcodes) are just for my case. I used

- USB Numeric keypad (I used Buffalo BSTK08MSV)
- Dot matrix LCD display (I used IIC LCD2004 type LCD)
- Arduino nano
- DC-DC up converter (3v to 5v)
- Walnut billet wood
- Blank PCB
- Acrylic plate
- Short parts (screws, electric wire, solder, etc.)”

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