I've finally found time to complete the bench testing of the laser control board with an Arduino Uno. The Uno was loaded with the LasaurApp firmware (a variation of Grbl). I used the LasaurApp web interface running on a Mac to exercise the motors, relays, etc. Here's a photo of my bench-test rig with one motor hooked up:
I used DB9, DB25, and RJ45 breadboard adapters to make it easy to jumper the various signals. My adapters came from Winford Engineering (
http://www.winfordeng.com) and they worked like a charm. I had to put the motor enable/disable jumper to "disable" so that the steppers to disabled whenever the Arduino Uno was powered down.
Running everything from the Arduino required a few changes to the LasaurApp firmware. First, the steps/mm had to be changed to match the Inventables stepper motors and the belts/pulleys in the buildlog.net 2.x design. Next the logic used for limit switch sensing (and sensing the status of the chiller) had to be inverted. Finally, the INVERT_AXIS defines had to be tweaked so that the motors turned the correct direction when responding to manual commands.
I've still got one more tweak to make to the firmware - homing the laser from the web interface results in driving the laser head away from the X end stop rather than toward it. More difficult (at least for me) will be adding Z controls to the web interface. None exist at the moment because (I think) the Lasersaur has no motor-drive on the Z axis.
And one other thing for anyone using Pololu stepper drivers, Inventable stepper motors, and the 3-axis laser control board. I got the wiring to work by using the wires in a Blue, Red, Green, Black sequence from left to right (when looking at the card edge with the TB1, TB2, and TB3 connectors.