KOVAX graphiCAL
Datasheet legend
Ab/c:
Fractions calculation
AC: Alternating current BaseN: Number base calculations Card: Magnetic card storage Cmem: Continuous memory Cond: Conditional execution Const: Scientific constants Cplx: Complex number arithmetic DC: Direct current Eqlib: Equation library Exp: Exponential/logarithmic functions Fin: Financial functions Grph: Graphing capability Hyp: Hyperbolic functions Ind: Indirect addressing Intg: Numerical integration Jump: Unconditional jump (GOTO) Lbl: Program labels LCD: Liquid Crystal Display LED: Light-Emitting Diode Li-ion: Lithium-ion rechargeable battery Lreg: Linear regression (2-variable statistics) mA: Milliamperes of current Mtrx: Matrix support NiCd: Nickel-Cadmium rechargeable battery NiMH: Nickel-metal-hydrite rechargeable battery Prnt: Printer RTC: Real-time clock Sdev: Standard deviation (1-variable statistics) Solv: Equation solver Subr: Subroutine call capability Symb: Symbolic computing Tape: Magnetic tape storage Trig: Trigonometric functions Units: Unit conversions VAC: Volts AC VDC: Volts DC |
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KOVAX graphiCAL
This ridiculously beautiful calculator is not a production model.
It is not even a prototype of a production model.
It is a "labor of love" by Gábor Kovács, a Hungarian engineer who took it upon himself to, well, build some beautiful calculators. Including graphiCAL that, although the name might suggest otherwise, is not a graphical calculator: rather, it is a very capable conventional programmable calculator, designed and built in the best traditions of Hewlett-Packard's classic machines, with RPN (Reverse Polish) logic.
The case looks manufactured, but it isn't: It's 3D-printed. The keyboard layout is interchangeable. In fact, I already received an updated keyboard layout from Gábor, matching the latest revision of the calculator's firmware.
Speaking of which, the calculator is still very much in active development. Its firmware is easily upgradeable thanks to its USB-C connector that is also used to charge its internal Li-ion battery.
Internally, the calculator is powered by a PIC microcontroller, with its firmware written in its entirely by Gábor, in the microcontroller's native machine language. Talk about true old school!
There are still a few software glitches but by and large, the calculator works well and works reliably. I daresay it's already one of my favorites. I especially like its well-lit, bright OLED display, which is a pleasure to look at. The display is large enough to show the calculator's full 4-level stack, or as many as 8 program steps at any given time.
To test graphiCAL's capabilities, I used an existing program, originally written for the HP-25C, that calculates the logarithm of the Gamma-function with roughly 8 decimal digits of accuracy. The program works "out of the box", pretty much, except that the HP-25C has no label keys and does not requires an R/S instruction to end program execution.
This program uses the expanded version of Stirling's formula. It computes the logarithm of the Gamma function for any positive argument and for all negative arguments where the Gamma function is positive; the result is usually accurate to more than 8 digits of precision. The program uses only the stack and the Last X register, leaving the calculator's memory registers alone.
000 LBL A
001 1
002 x<>y
003 9
004 x<y
005 GTO 012
006 Rv
007 ÷
008 LAST x
009 1
010 +
011 GTO 003
012 Rv
013 ENTER^
014 ENTER^
015 Rv
016 Rv
017 2
018 ÷
019 π
020 ÷
021 √x
022 ÷
023 ln
024 Rv
025 Rv
026 ln
027 ×
028 +
029 x<>y
030 -
031 x<>y
032 x2
033 1/x
034 3
035 0
036 ÷
037 1
038 -
039 Rv
040 Rv
041 Rv
042 ÷
043 1
044 2
045 ÷
046 -
047 R/S