[Swansea Hackspace] An old PC with parallel printer port?

[Justin Mitchell]

On Wed, 2014-09-17 at 11:44 +0100, Justin Mitchell wrote:
> So after we have jury rigged one using a standard arduino, we can then
> mill the pcb for a custom made one :)
> 
> On Wed, 2014-09-17 at 11:39 +0100, Gerrit Niezen wrote:
> > It seems a solution appeared on Hackaday the same day that you were
> > discussing the problem:
> > http://hackaday.com/2014/09/16/usb-to-db25-adapter-uses-grbl-for-parallel-port-cnc-communication/
> > 
> > 
> > Guess what: It’s Arduino-based and runs GRBL.

This also seems to apply to laser cutters, at least the cheap ones with
parallel port connectors. They appear to be the same level of dumb
step-stick style driver inputs that many CNC machines are.

So a cheap laser cutter could be adapted to work (the supplied software
is notoriously bad) without even changing the electronics.

Further research has shown that these cheap cutters tend to have two
control boards, one is the psu, and connects to the safety interlocks,
the HV laser tube drive, stop switch, etc.  this in turn gives 5v, laser
trigger, and motor drive voltage (24V?) outputs.

the second board is then the stepper controller / interface board,
theres often just two steppers X/Y, end stops, and the TTL level laser
on/off trigger, which can be driven with PWM for finer control.

So replacing the stepper controller with something more modern is going
to be pretty easy if you need to, but if its a parallel port one you can
just as easily put an arduino with GRBL/Marlin on the outside and get
the same level of control.