RPN scientific calculator firmware for $13 calculator kit

[jklsadf]

Glad it worked out for you!

I did print out your template in color a while back, and have been meaning to solder up a second kit with better components (FSTN LCD, Omron tactile switches, and shorter screws into 12mm standoffs instead of the super long screw and nut provided). Someday...also the trig functions when I have time. (The log/exponential functions were a lot more motivating, because with those gave calculating arbitrary powers. Trigs I rarely use, and there's usually at least 3 calculators and sometimes a slide rule on my desk with trigs on the rare occasion I do need them.)

I'd be surprised if you could get the original hex file, since it's not on the website, although luckily they at least included the full schematic. There do seem to be multiple sellers on eBay, so maybe the hex file is out there somewhere. They might all be the same seller though, or from the same original source, since most of the sellers do seem to be in Shen Zhen. I would be interested in knowing how much flash space the original firmware used.