Collect the parts you'll need:
- ATmega168 chip
- .1uf capacitor (ceramic, polyester, etc. doesn't matter so much; value .047uf-.47uf should be fine)
- 10K resistor (values ~3.3k-20k should work fine)
- Short lengths of wire
Program the Bootloader with your AVR programmer:
You will want to use the lilypad bootloader (included in with release Arduino-0010, in the hardware/bootloaders/lilypad). Using your AVR programmer, flash the bootloader. For example, on my OSX system:
avrdude -C /Applications/Arduino-0010/hardware/tools/avr/etc/avrdude.conf -cusbtiny -pm168 -Pusb -e -u -Ulock:w:0x3f:m
avrdude -C /Applications/Arduino-0010/hardware/tools/avr/etc/avrdude.conf -c usbtiny -pm168 -Pusb -Uflash:w:LilyPadBOOT_168.hex -Ulock:w:0x0f:m
avrdude -C /Applications/Arduino-0010/hardware/tools/avr/etc/avrdude.conf -cusbtiny -pm168 -Pusb -e -u -Uefuse:w:0x00:m -Uhfuse:w:0xdd:m -Ulfuse:w:0xf2:m
Set up the breadboard:
Put the ATmega168 in the breadboard, straddling the center.
For each of the following connections, use the hole at each ATmega168 pin that is the closest to the chip that is open; this will leave the last hole in each of the rows 1-8 open for the programming cable to plug into.
Connect pin 7 and 20 with a length of wire (VCC to AVCC)
Connect pin 8 and 22 with a length of wire (GND to AGND)
Connect the 10K resistor from pin 1 to pin 7 (RES to VCC) *
Connect the .1uf capacitor from pin 7 to pin 8
If you have power bus lines on your breadboard, I suggest connecting the + rail (red) to pin 20 and the - rail (blue) to pin 22. This is somewhat bad form (connecting to the analog side for power connections for other stuff), but if your breadboard is the same size as mine you've already filled all of the holes available for pin 7.
If you're planning to use USB power, you can now just plug in the programming cable and upload sketches to the board (make sure to connect the power selection pins on the cable adapter with a jumper to power the chip from USB).
Otherwise you'll need to use a battery/voltage regulator/etc. to supply power. Note that you will want to always use 5v for programming via Arduino software; other voltages will cause the clock speed to vary significantly and will likely cause communication (and thus programming) to fail.
When you go to upload sketches to this style of board that uses the internal oscillator, select "Lilypad Arduino" from the Tools/Board menu.
- 2008 10-02 FIXED -- was incorrectly put as pin 1 to pin 10 in original