Mitxela (Tim Alex Jacobs) did the firmware based on the VUSB Easylogger code, and points to that if you want to rebuild it. If you are happy with the base functionality, you can just burn the hex file.

Note: if you want to program the attiny85 in place, do so before soldering on the buzzer, as it overlaps with connector. I have some long headers that I stick in my programmer's cable and wedge it in the holes for a temporary connection to keep from having a big sticky-up header..

I copied the easylogger source and merged it with mitxela's morsekey main.c. I also edited the Makefile to change the processor type (easylogger used attiny45) and programmer (I use usbtinyisp).

If you want to change the programmer, it's an easy edit in the Makefile.

First burn the fuses:

• make fuse

which essentially does:

• avrdude -c usbtiny -p attiny85 -U hfuse:w:0xdd:m -U lfuse:w:0xc1:m

and then

• make flash

which is

• avrdude -c usbtiny -p attiny85 -U flash:w:main.hex:i