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 DemUino machines are microcontroller based computers using the arduino/sanguino hardware libraries. The heart of each system is a simple command interpreter that also supports mathematical expressions in RPN. I had to remove a few of the different implementations in order to make it more practical to update the posted firmware. Use either IDE 1.6.5 or IDE 1.6.12 as suggested to compile the source code. In general 1.6.5 produces a larger flash image.

Nick Gammon's High-voltage programmer for AVR chips
Recover your bricked atmega328p by changing the fuses.
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.

ver 5.0 


  • atmega328p
  • 5 key maps
  • BigNumber & avr-libc
  • Scientific/programmer
  • Stack based X,Y, Z & T registers.
  • Standard/scientific notation
  • Transfer Function  s/z/real.
  • User defined system settings.   
  • Clock display.
  • Low battery drain <2mA min. 
  • Auto shutdown less than 1uA

version 3.6

  • Uses a single atmega328p and an LM386 amplifier
  • Plays 8bit PCM uncompressed raw music data
  • 8-bit R-2R DAC, 4 navigation keys, 8x2 LCD, 0.5W amp
  • 2xAAA batteries or USB operation and charging
  • 8, 11, 16 and 22 KSPS sample rates
  • clock and alarm functionality
  • Records from external source at 8, 11 and 16KSPS
  • DDS for low frequency audio tones


DemUino Portable v3.93
with built-in


Use IDE 1.6.12 for compiling.

  • atmega644p + atmega328p
  • atmega328p runs the built-in keypads with 44 keys
  • PS/2 keyboard in addition to the keypads
  • SD-FAT support.
  •  Includes floating point RPN math, expressions 
  • convolution, DFT, z and s tranforms
  • audio low frequency DDS
  • clock and alarm functionality

version 2.998
with built-in



Use IDE 1.6.12 for compiling.

  • 2 x  atmega328p
  • PS/2 keyboard
  • SD-FAT support. 
  • Includes floating point RPN math calculations, 
  • DFT, convolution, z and s transforms, 
  • 8-bit raw music file playback.
  • audio low frequency DDS
  • clock functionality
version 1.3


Use IDE 1.6.12 for compiling.

  • atmega644p
  • nokia 5110 LCD graphics
  • SD-FAT support. 
  • 4x4 keypad - 8 keymaps
  • RS232 control. 
  • Ifloating point RPN math calculations, 
  • DFT, convolution, z and s transforms, 
  • Graphics primitives

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.