running a "skycam" laser cutter from anet a8 board and parts

[curious aardvark]

I think this is a case of too little, too late.

'please write me a custom firmware for an unknown motherboard, by the way I need it tomorrow.'

The board should have some form of idnetification printed on it - that would be somewhere to start.
Not all anet a8 kits will come with the same boards, the machine has been around for a while and no doubt the manufacturers have found and changed to cheaper parts and suppliers a number of times.

Also you need to power the laser from the extruder connector - NOT the fan connector. gcode for switching the extruder on and off during movement is already incorporated into the firmware.
Fan on and off is usually layer specific.

This is a complicated and long term project. Not something to rattle off in a few hours and expect it to actually work.