RPN Scientific Firmware for the Spikenzielabs Calculator Kit

[Maximilian Hohmann]

Hello!

Old thread ... new developments :-)

The Chinese kit manufacturers came up with yet another calculator kit which might be the basis for DIY projects. This one comes with a 2x16 characters inverse backlit dot-matrix LCD screen and 20 keys, mounted in a very smart laser-cut acrylic housing with slanted display. Power comes from 2 2032 Lithium cells (not included in my kit). Why this one needs two cells as opposed to the LED calculator above which only needs one I don't know.

I assembled mine in less than two hours, there is not much soldering to do but cutting out the key labels and fiddling them into the keys takes some time.

Apart from being a basic calculator (no operator precedence or other smart features installed) it comes with three pre-programmed applications which are selected with the "mode" key: Calculate resistor values form their color code, calculate resistors required to operate LEDs and a simple HEX<>DEC converter.

Unfortunately this time they did not use an Atmega 328 processor (esily programmed in the Arduino environment with lots of resources awailable) but a chip called "15W413AS" about which I could not find a lot of useful information yet.

These are the bulding instructions: http://www.diyleyuan.com/jc/L8Q.html and below are some pictures of my kit and the finished calculaor. Maybe someone finds this interesting... Ah yes, I paid 11,95 Euros shipping included. Buying the parts individually would have cost more I guess!

Regards
Max