in your arduino sketch folder (often Documents/Arduino)
add a folder called hardware (if it doesn’t exist
then, inside hardware, create another folder with an arbitrary name (maybe fabBoards?)
then, inside that folder, create another folder named avr
then, inside avr, create a text file named boards.txt with the information below:
so, on my machine, all of that looks like:
Users/Will/Documents/Arduino/hardware/fabBoards/avr/boards.txt
hello.name=hello.arduino, ATmega328P, 5V, 8MHz internal oscillator hello.upload.protocol=arduino hello.upload.maximum_size=30720 hello.upload.speed=57600 hello.bootloader.low_fuses=0xE2 hello.bootloader.high_fuses=0xDA hello.bootloader.extended_fuses=0x07 hello.bootloader.path=arduino:atmega hello.bootloader.file=ATmegaBOOT_168_atmega328_pro_8MHz.hex hello.bootloader.unlock_bits=0x3F hello.bootloader.lock_bits=0x0F hello.build.mcu=atmega328p hello.build.f_cpu=8000000L hello.build.core=arduino:arduino hello.build.variant=arduino:standard
with just these steps, the board should show up in your list of boards when you close and restart Arduino.
in the new versions of Arduino, they’ve been organizing the boards in a new way with what they call “platforms”. If you want to make more similar boards and organize them under a subheading in the boards menu, you can create a platforms.txt file which names the heading and (optionally) provides additional compiler information.
In this case, it can be as simple as:
name=Fab Boards version=0.0.1