Controling laser show through Gcode planner

[Murilolana]

Hi,

My name is Murilo, I’m a Brazilian product developer, DIY enthusiast, and wish to build a galvo based 3d printer. Of course, I wish to share all info, like it’s done with any other open source project.

My idea is to use mach3 or similar Gcode planner to control the galvo system, therefore I could generate tool paths related to the beam diameter to project the layers… If I’m sure, Skeinforge generates Gcode from the STL slices for RepRap fdm printers. In case of using galvos, the layers would be projected super-fast.

I’m a newb on programing and electronics and don’t know how this could work. In my mind the hardware chain would be: PC (mach3) -> show card DAC -> galvo drivers. The thing is I don’t know if an intermediate hardware is needed between the PC and the show card in order to make them understand each other. Mach3 outputs step/pulse TTL signals, but I don’t know if this signals would be interpreted correctly by the show card.
I’ve read on the forum about the Open Laser Show DAC (or OLSD for short). Can anyone tell if it is capable of doing this job?
I think I’m gonna buy a cheap galvo kit on eBay to begin some tests…

Please, any ideas on how to setup this?

Chears,


Murilo

[laserist]

Scanners have amplifiers that produce an angular swing with offset - your stepper driver signals are linear and while they could be interpreted you would have to correct for the height of the scanning system over the working plane....

[Murilolana]

Thank you for your reply.
Do you mean f-theta? To correct the spherical focus distance?

One of the things I'm trying to figure out is what kind of input signals a interface show card needs to drive the galvos. I mean, a gcode planner outputs step/directions signals, so, is there a way the show card could interpret these TTL signals to produce the -5V/+5V to the drivers?