CrossRoads:
What part of the Arduino functionality would you like to keep?
At a minimum you need:
the '328P
16 MHz crystral
two 22pF caps
100nF caps on VCC, AVCC pins using analog? need 100nF cap on the Aref pin 10K reset pullup resistor diode such as 1N4158 across the resistor (anode to reset pin, cathode to Vcc)
optional:
Header pins to connect FTDI Basic/FTDI cable, and 100nF cap to connect to Reset pin
or
header pins to connect to ICSP header for rebootloading or for installing bootloaderless sketches
place to connect 5V wallwart, or a battery, or a 5V regulator
Here's an example for a ATmega1284P type board, a '328P would use a smaller connector
This one has both FTDI and ICSP headers, but does not have the diode.
It has screw terminal for bring in 5V power from a wallwart or 4.5V from a triple-AA battery pack (I've used both)
CrossRoads:
What part of the Arduino functionality would you like to keep?
At a minimum you need:
the '328P
16 MHz crystral
two 22pF caps
100nF caps on VCC, AVCC pins using analog? need 100nF cap on the Aref pin 10K reset pullup resistor diode such as 1N4158 across the resistor (anode to reset pin, cathode to Vcc)
optional:
Header pins to connect FTDI Basic/FTDI cable, and 100nF cap to connect to Reset pin
or
header pins to connect to ICSP header for rebootloading or for installing bootloaderless sketches
place to connect 5V wallwart, or a battery, or a 5V regulator
Here's an example for a ATmega1284P type board, a '328P would use a smaller connector
This one has both FTDI and ICSP headers, but does not have the diode.
It has screw terminal for bring in 5V power from a wallwart or 4.5V from a triple-AA battery pack (I've used both)
Please send it so I can try it out first. I'm pretty sure that it will work great here in Finland, but you never know. Anyway, if I ever where to use that thing I will solder a pull-up on the back to make you happy, but not a cap! Living on the edge! :%
my bad - i saw "shrinkify" only a few hours earlier did i come across "how to shrinkify your arduino" via a youtube vid, i presumed you were using an Attiny, my bad.
well, there's plenty of options, shift registers are the best way to go if all you're doing is reading a bunch of high/low signals.
www.solarbotics.com - the ardweeny originator?
"And Mr. Kimio Kosaka's "One-Chip-Arduino" project inspired us to develop the Ardweeny; the smallest Arduino you can solder yourself with through-hole components!"
fungus:
How about this one: arduino pro mini for sale | eBay
Under $4 for a small-footprint Mega328 device with voltage regulator, etc. It's simply not worth making your own these days...
I posed a link to the site however.. where he DOES share the schematic (dont recall if a .brd file is there?.. or just an image of the schematic)
as for the one I made/home etched (with the voltage regulator on-board)..... why? as mentioned, now-a-days you can get a real one mini/nano for $4.00 or so..