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Welcome to my little shop of art and stuff where everything is free for non-commercial use. In case you find something useful proper credit will be greatly appreciated. I am an occasional hobbyist in the field of drawing/painting and somewhat more active in electronics. Both aspects are presented in the following pages.

The Art Gallery features experiments using ballpoint pens, dry media and some oil paint.

The Electric Circuits page lists a number of excerpts, mostly elementary and others partly drawn from earlier work in the field of analog electronics that overall might be of some educational value. 

The DemCalc machines are more recent in the line of computers.They are based, in one form or another, on RPN structures and especially for the DemCalcProg implementation the core supports nested expressions and control structures using recursion. Use IDE 1.8.13 to compile the source.

The DemUino machines are no longer supported.

Nick Gammon's High-voltage programmer for AVR chips

Recover your bricked atmega328p by changing the fuses.

Note:

If you don't have available a p-mosfet for the RESET circuit you can use a PNP BJT such as the complementary of 2N3904 - the 2N3906 - driven with a 10K or smaller resistor from the collector of 2N3904 to its base. The small resistor will ensure saturation of the CE junction; also, you will need a load of a few KOhms (I used 2.2K - use 3.3K,4.7K etc) from its collector to GND. Its collector also connects to the RESET pin of the target.

Instead of the 2N3904-6, I used a pair of BC546-BC556 BJT transistors.

 

 STACK BASED RPN SCIENTIFIC CALCULATORS

COMMON HARDWARE

DemCalcProg5

Programmable RPN Calculator - version  2.87h

comprehensive programming model with dynamic buffers, user defined variables with resizable strings


Use IDE 1.8.13 for compiling.

v2.87d archived

v2.87h  PDF documentation

v2.87h  SOURCE & ALL

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DemCalcBC

Arbitrary Precision RPN Calculator

ver 6a

Use IDE 1.8.13 for compiling.

v6a PDF documentation

v6a SOURCE & ALL

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DemCalc64

Double Precision RPN Calculator

ver 3.0

Use IDE 1.8.13 for compiling.

v3.0 PDF documentation

v3.0 SOURCE & ALL



Programmable fonts used by DemCalcProg machines




A 0 49 (1 A * SIN d[A] =) FOR

d[A 51 -] d[A 50 -] + 1 T - d[A 1 -] * - 1 T + / d[A] =

                 CmpCalc_PICO

                 SCIENTIFIC RPN CALCULATOR  v1.2

 with native support for complex numbers and BigNumbers

                                      FEATURES

PDF documentation

SOURCES & BINARY



If you have comments or questions you can either contact me at biromaster@yahoo.com or if you have a google account you can first sign in and then leave a comment at the bottom of the corresponding page.

Thanks for visiting and I hope you enjoy your stay.