I’m on the verge of modifying my printer for bed auto leveling.
I’ll power the necessary servo from a simple voltage regulator circuit connected directly to the power supply input. Regarding the signal to the servo, I just plan on using any of the loads of unused pins on the ATmega2560.
As i can read from the schematic on http://www.open-electronics.org/a-new-board-for-the-3drag-theres-more-than-sanguinololu/
only 50 of the 100 pins are in use, and I should basically just be able to pick any one at random of the unused ones.
That leads to my question: does anyone with or without access to the PCB schematics know of any unused pins being connected to any test point or the like that would be easily accessed and soldered to. I would very much like not having to solder directly to the MCU’s legs (I always end up breaking stuff that way … >.<). I will disassemble my child and cat proofing printer cabinet and check the board myself tonight when the kids are asleep, but it would be awesome if someone on forehand knew of a good place to start.